Publication List

Halogen bonding (XB) is a highly-directional class of intermolecular interactions that has been used as a powerful tool to drive the design of crystals in the solid phase. To date, the majority of XB donors have been iodine-containing compounds, with many fewer involving brominated analogues. We report the formation of adducts in the vapour phase from a series of dibromoperfluoroalkyl compounds, BrCF2(CF2)nCF2Br (n = 2, 4, 6), and 1,4-diazabicyclo[2.2.2]octane (DABCO). Single-crystal X-ray diffraction studies of the colourless crystals identified 1,4-diazabicyclo[2.2.2]octane–1,4-dibromoperfluorobutane (1/1), C4Br2F8.C6H12N2, (I), 1,4-diazabicyclo[2.2.2]octane–1,6-dibromoperfluorohexane (1/1), C6 Br2F12.C6H12N2, (II), and 1,4-diazabicyclo[2.2.2]octane–1,8-di-bromoperfluorooctane (1/1), C 8Br2F16.C6H 12N2, (III), each of which displays a one-dimensional halogen-bonded network. All three adducts exhibit N...Br distances less than the sum of the van der Waals radii, with butane analogue (I) showing the shortest N...Br halogen-bond distances yet reported between a bromoperfluorocarbon and a nitrogen base [2.809 (3) and 2.818 (3) Å], which are 0.58 and 0.59 Å shorter than the sum of the van der Waals radii.

The new stable perfluoropropenyl organometallic complexes [(Ph3P)Au(E-CF = CFCF3)], trans-[(Ph3P)2Pt(Z-CF = CFCF3)Cl], trans-[(Ph3P)2Pd(E-CF = CFCF3)Cl], [(COD)Pt(E-CF = CFCF3)2] and [Cp2Ti(E-CF = CFCF3)Cl] have been obtained from the reaction of LiCF = CFCF3–derived from Z-CFHdouble bond; length as m-dashCFCF3 (HFC-1225ye) − with appropriate transition-metal starting materials. The complexes have been characterized by multinuclear NMR studies (19F,1H, 31P and 13C) and single-crystal structure determinations. Based on the X-ray derived data a comparison is made between σ-bound perfluoropropenyl and perfluorovinyl ligands; whilst they are found to be electronically quite similar on the basis of their trans-influence the perfluoropropenyl group is significantly more sterically-demanding, and it is suggested that this accounts for the predominance of mono-perfluoropropenyl-substituted complexes with enhanced stabilities.

A number of gold(I) and gold(III) complexes have been prepared, many of which feature chiral ligands, and their application to A3-coupling reactions is presented. Gold(III) complexes were found to be particularly effective catalysts for the coupling in a range of solvents, however no asymmetric induction was obtained when using chiral gold complexes and the rate of product formation was found to be similar even when using different ligand systems. In-situ NMR analysis of these reactions indicates that decomposition of the catalyst occurs during the course of the reaction while TEM studies revealed the presence of gold nanoparticles in crude reaction mixtures. Taken together these data suggest that the gold nanoparticales, rather than the intact gold complexes, could be the catalytically active species, and if so this may have significant implications for other gold-catalysed systems.

A series of new perfluoropropenyl-containing phosphines of the type R(3-n)P(E-CF=CFCF3)n (R = Ph, iPr, n = 1, 2; R = tBu, n = 2) have been prepared from the reaction of the hydrofluoroolefin Z-CF3CF=CFH (HFO-1225ye) with base and the appropriate chlorophosphine, while reaction with Cl2PCH2CH2PCl2 gave (CF3CF=CF)2PCH2CH2P(CF=CFCF3)2, the first example of a bidentate fluoroalkenyl-containing phosphine. An alternative route to these phosphines based on the room- or low-temperature deprotonation of CF3CF2CH2F (HFC-236ea) gives mainly the E- isomer, but also a small amount of the Z- isomer, the ratio of which depends on the reaction temperature. All of the phosphines could be readily oxidised with either H 2 O 2 or urea.H 2O2, and the phosphine selenides R(3-n)P(Se)(E-CF=CFCF3)n (R = Ph, n=1,2; R = iPr, n=1; R = tBu, n=2) were prepared. The steric and electronic properties of these ligands were determined based on their platinum(II), palladium(II) and molybdenum carbonyl complexes. The crystal structures of (CF3CF=CF)2PCH2CH2P(CF=CFCF3)2, (CF3CF=CF)2P(O)CH2CH2P(O)(CF=CFCF3)2, iPr2P(Se)(CF=CFCF3)2 , trans-[PtCl2Ph(3-n)P(E-CF=CFCF3)n2] (n = 1 or 2), trans-[PdCl2R2P(E-CF=CFCF3)2] (R = Ph, iPr) and [Mo(CO)4(CF3CF=CF)2PCH2CH2P(CF=CFCF3)2] are reported.

Halogen bonding is an intermolecular interaction capable of being used to direct extended structures. Typical halogen-bonding systems involve a noncovalent interaction between a Lewis base, such as an amine, as an acceptor and a halogen atom of a halofluorocarbon as a donor. Vapour-phase diffusion of 1,4-diazabicyclo[2.2.2]octane (DABCO) with 1,2-dibromotetrafluoroethane results in crystals of the 1:1 adduct, C2Br2F4ÁC6H12N2, which crystallizes as an infinite one-dimensional polymeric structure linked by intermolecular N-Br halogen bonds [2.829 (3) A ], which are 0.57 A shorter than the sum of the van der Waals radii.

Gold-catalyzed A3-reactions proceed efficiently when conducted in 2,2,2-trifluoroethanol as solvent. The rates of these reactions are accelerated considerably when conducted in a microwave reactor.

The formation of quaternary ammonium iodides possessing a fluorine-containing chain has been investigated. Reactions of tertiary amines, such as i-PrMe2N and n-BuMe2N with I(CH2)n(CF2)m(CF3), (n = 2, m = 5 and 7) do not cleanly yield the anticipated quaternary ammonium halide salt, instead elimination occurs and [RMe2NH]I (R = i-Pr, n-Bu) and CH2=CH(CF2)m(CF3) are formed. This is confirmed by the crystallographic characterisation of [n-BuMe2NH]I which is found to adopt a micellar-type arrangement in the solid state. Increasing the spacer chain-length to n = 3 does result in the desired quaternary ammonium halide salts, [RMe2N(CH2) 3(CF2)m(CF3)]I, (m = 3, 7). Quaternisation of MeBuN((CH2)3C8F17) with 1-iodooctane gave the asymmetric quaternary ammonium salt possessing a fluorinated alkyl chain, [n-BuMeOctN((CH2)3C8F17)]I. Unlike in previously studied perprotio systems, low symmetry ammonium systems possessing long fluorinated chains do not result in room temperature ionic liquids.

This review describes recent advances in the synthesis, chemistry and applications of phosphine ligands containing one or more perfluoroalkyl, Rf , substituent. The methods reviewed are capable of generating a wide variety of monodentate, bidentate and PCP-pincer ligands containing Rf groups. Based on the chemistry of complexes containing these ligands, and compilations of their spectroscopic data and structural parameters it is shown that fluoroalkyl-containing phosphines have a distinct combination of steric and electronic properties, often quite different to fluoroaryl analogues. The catalytic activities displayed by complexes of these ligands are described.

The reactions of the group 15 trihalides, MX3 (M = As, Sb, Bi; X = Cl, Br), with the phosphine selenide SeP(p-FC6H4)3 result in the formation of co-crystals of formula MX3$\cdot$SeP(p-FC6H4)3. No reaction was observed with MI3 (M = As, Sb, Bi). The structures of MX3.SeP( p-FC6H4)3 (M = As, X = Br 2; M = Sb, X = Cl 3; M = Bi, X = Cl 5; M = Bi, X = Br 6) have been established, and are isomorphous, crystallising in the cubic I23 space group. All the structures feature a primary MX3 unit, which has three weak secondary M...Se interactions to SeP(p-FC6H4)3 molecules. However, each of these SeP(p-FC6H4)3 molecules bridges three MX3 molecules, resulting in the generation of an M4Se4 (M = As, Sb, Bi) distorted cuboid linked by the pnictogen-chalcogen interactions. Four opposing corners of the cuboid are occupied by the M atom (M = As, Sb, Bi) of an MX3 pyramid, and the other four by the selenium atom of the phosphine selenide.

A series of new (E)-pentafluoropropenyl complexes of Hg, Ge, Sn, and Pb are reported derived from CFH=CFCF3 ((Z)-HFC-1225ye). Unequivocal assignment of the geometry of the products was achieved via a multi-nuclear (1H, 13C, 19F, 119Sn, and 199Hg) NMR study. These conclusions are confirmed in the single-crystal X-ray structures of Ph3Ge(CF=CFCF3) and Ph3Sn(CF=CFCF3). In the solid-state structures of both molecules, short contacts are observed between one of the fluorine atoms of the CF3 group and the metal center. The Bu3Sn(CF=CFCF3) compound acts as an effective source of the pentafluoropropenyl group in a series of palladium-catalyzed Stille-Liebeskind reactions to generate new aryl-pentafluoropropenyl systems.

A series of gold(I) phosphine complexes of the type [AuClPR2(Rf)] (R = Et, i-Pr, Cy; Rf = CF=CF2; R = Ph, Rf = CF=CFH, CCl=CF2, CCCF3, CF3, i-C3F7, s-C4F9) have been prepared and most have been structurally characterised. All of the complexes are monomeric in the solid state, and a number of secondary interactions are observed - including short intramolecular AuF distances, metal-bound Au-ClH non-classical hydrogen bonds, fluorous domains and phenyl embraces. Only in the case of [AuClPEt2(CF=CF2)] is an aurophilic interaction with an Au...Au contact less than the sum of the van der Waals radii observed. Even then, the distance, 3.3458(10) Å, is longer than that previously observed for the related complex with R = Ph; Rf = CF=CF2.

Cyclometallated gold(III) complexes containing functionalised (2-dimethylaminomethyl)phenyl ligands have been prepared by transmetallation from boroxines to sodium tetrachloroaurate.

The coordination chemistry of the fluorovinyl substituted phosphines PPh2(Z-CF=CFH) and PPh2(E-CCl=CFH) with K2MX4 (M = Pd, Pt; X = Cl, Br, and I) salts has been investigated resulting in the first reported palladium(II) and platinum(II) complexes of phosphines containing partially fluorinated vinyl groups. The complexes have been characterised by a combination of multinuclear [1H, 13C, 19F, 31P] NMR spectroscopy, and IR/Raman spectroscopy. The single-crystal X-ray structures of 5CFH)2], X = Cl (1), Br (2), I (3), trans-[PdCl2(PPh2(CCl=CFH))2] (4), cis-trans-[PdX2(PPh2(CF=CFH)2], X = Cl (5), Br (6), trans-[PtI2(PPh2(CF=CFH))2] (7), and both cis- and trans-[PtX2(PPh2(CF=CFH))2] (8), have been determined. Results obtained from spectroscopic and [PtCl2(PPh2(CCl= crystallographic data suggest that replacement of a b-fluorine by hydrogen, whilst reducing the steric demand of the ligand, has little effect on the electronic character of the ligand. The presence of a proton in the vinyl group results in short proton-halide secondary interactions in the solid state (d(HÁ Á ÁX) = 2.72(3) for 1, and 2.92(5) A for 2) forming an infinite chain ribbon motif.

The reaction of trimethylsilyl-containing phosphanes with perfluoroiodoalkanes provides a general and convenient route to perfluoroalkyl-containing phosphanes.

A review of the methods for the preparation of P(III) compounds containing directly bound fluoroalkenyl,fluoroalkynyl and fluoroalkyl groups is given. Recent advances in the synthesis of organofluoro-containing phosphines are reported,including a new high yielding route to bulky fluoroalkyl-containing phosphines.

A series of Mn(II) macrocyclic Schi?-base complexes [MnLn]2+ have been prepared via the Mn(II) templated [1+1]cyclocondensationof 2,9-dicarboxaldehyde-1,10-phenanthroline with appropriate linear and branched amines. In this way ligands the pentaaza macrocycleL1 which is 15-membered and L2 which is 16-membered possessing no pendant arm,L6 is 15-membered with one 2-aminoethyl pendant arm and L8 which is 18-membered hexaaza macrocycle with two 2-aminoethyl pendant arms are formed. All the complexes have been characterized using spectroscopic methods. The crystal structures of [MnL8](ClO4)2.EtOH were determined and indicate that in the solid state the complex adopts a slightly distorted hexagonal bipyramid geometry with the Mn(II) ion located within a hexaaza macro-cycle with the two pendant amines coordinating in the axial positions.(c)2007 Elsevier B.V. All rights reserved.

The coordination chemistry of the perfluorovinyl phosphines PEt2(CFCF2),PiPr2(CFCF2),PCy2(CFCF2) and PPh(CFCF2)2 to rhodium(I),palladium(II),and platinum(II) centres has been investigated. The electronic properties of the ligands are estimated based on (CO) and 1J(Rh-P) values. X-Ray diffraction data for the square-planar Pd(II) and Pt(II) perfluorovinyl-phosphine containing complexes allow estimates of the steric demand for the series of ligands PPh2(CFCF2),PEt2(CFCF2),PiPr2(CFCF2),PCy2(CFCF2) and PPh(CFCF2)2 to be determined. The (CFCF2) fragment is found to be more electron withdrawing than (C6F5) yet sterically less demanding. These ligands therefore provide a range of electron-neutral to phosphite-like electronic properties combined with a range of steric demands. This study also reveals that short intramolecular interactions from the metal centre to the-fluorine atom cis to phosphorus of the CFCF2 groups are observed in all-trans square planar complexes of the ligands. Unusually,the complex [PtCl2PiPr2(CFCF2)2] crystallises with both cis-and trans-isomers present in the unit cell. It appears that co-crystallisation of both isomers occurs in order to maximise fluorous regions in the crystal packing,and the extended structure displays short fluorine?fluorine contacts. The generation of mixed geometries seems to be a phenomenon of crystallisation, as solution phase NMR studies reveal the presence of only the trans-isomer.

The effect on the melting point of the introduction of asymmetry in tetraalkylammonium halide salts has been investigated leading to the synthesis of new,hydrophobic (room temperature) ionic liquids suitable for liquid/liquid electrochemistry; one of these,tri(hexyl)decylammonium tetrakis(pentafluorophenyl)borate,displays the largest electrochemical window observed to date for a biphasic room temperature ionic liquid system.

Complexes of three Cd(II)-contg. macrocyclic Schiff base complexes contg. a phenanthroline ligand (L) [CdLn(Cl)]+ (n = 2,3,4),were prepd. via [1 + 1]cyclocondensation of 2,9-dicarboxaldehyde-1,10-phenanthroline and a no. of linear triamines via a metal-templated reaction and coordination features were examd. The ligands,L,are 16-,17-,and 18-membered pentaaza macrocycles and all the complexes incorporate a 1,10-phenanthroline unit as an integral part of their cyclic structure. The complexes were characterized by a variety of methods including IR,1H,13C,DEPT,COSY(H,H) and HMQC(H,C) NMR studies and MALDI mass spectrometry. The polymeric structure of [CdL2(Cl)]nn+ was detd. by x-ray crystallog.,which showed that the complex cation consisted of a pentagonal bipyramidally coordinated Cd(II) ion. The seven-coordinated Cd(II) ion is ligated by the five N atoms of the macrocycle in the equatorial plane and has two bridging chloride ligands in the axial positions resulting in a ribbon of such complex ions. Supporting ab initio HF-MO calcns. were undertaken using the std. 3-21G* and 6-31G* basis sets. [on SciFinder (R)]

In the title compd.,[Cu(C24H34N6O2)](ClO4)2,the copper(II) coordination geometry is intermediate between square-based-pyramidal and trigonal-bipyramidal. The H atoms of the sixth non-metal-coordinating nitrogen donor engage in intramol. hydrogen bonding with the ethoxy O atom and the uncoordinated phenanthroline N atom. Hydrogen bonding is also obsd. between the NH2 H atoms and two of the phenanthroline H atoms with the perchlorate anions. [on SciFinder (R)]

The asym. fluorovinyl mercurials RHgCX:CF2 (X = F,R = Ph (79%yield),R = Fc (93%); X = Cl,R = Ph (88%),R = Fc (89%)) were prepd. from RHgCl and LiCX:CF2,the later being derived from the reaction of CF3CH2F (X = F) or CF3CH2Cl (X = Cl) and BuLi. All the complexes were fully characterized by spectroscopic methods and,apart from PhHgCCl:CF2,the compds. are sufficiently stable to be studied by single-crystal x-ray diffraction,making this the 1st report of structurally characterized asym. fluorovinyl mercurial complexes RHg(CX:CF2). In the solid state all of the structurally characterized complexes demonstrate asym. Hg-C distances and extensive intramol. Hg...F and Hg...h2-arene interactions are obsd.

Raman data suggest that a crystallog. detd. Cl3CD...F2BF2-interaction in the solid-state structure of [Ru(CNBut)(CO)(h2-C6H4-2-CHO)(PPh3)2][BF4].2CDCl3 is an example of a blue-shifting bifurcated hydrogen bond. The n(C-D) band blue-shifts 5 cm-1 to 2269 cm-1 compared to 2264 cm-1 for CDCl3 in the gas phase and 20 cm-1 from frozen CDCl3 at 2249 cm-1. A conventional interpretation of these band shifts would suggest that the CCl2 fragment of DCCl3 is a stronger hydrogen-bond acceptor than the BF2 fragment of a BF4-group. [on SciFinder (R)]

This chapter reviews the literature reported during 2006 on the elemental halogens and the noble gases,and compds. contg. these elements in their pos. oxidn. states.

The trifluorovinyl phosphine complexes [Cp*RhCl2PR3-x(CF=CF2)x](1 x = 1,a R = Ph,b Pri,c Et; 2 x = 2,R = Ph) have been prepd. by treatment of [Cp*RhCl(m-Cl)]2 with the relevant phosphine. The salt [Cp*RhCl(CNBut)PPh2(CF=CF2)]BF4,3,was prepd. by addn. of ButNC to 1a in the presence of NaBF4. The salt [Cp*RhClkP,kS-(CF2 =CF)PPh(C6H4SMe-2)]BF4 was prepd. as a mixt. of cis (5a) and trans (5b) isomers by treatment of [Cp*RhCl(m-Cl)]2 with the phosphine-thioether (CF2=CF)PPh(C6H4SMe-2),4,in the presence of NaBF4. The structures of 1a-c and 5a have been detd. by single-crystal X-ray diffraction. Intramol. dehydrofluorinative carbon-carbon coupling between pentamethylcyclopentadienyl and trifluorovinylphosphine ligands of 1a,3 and 5 has been attempted. No reaction was obsd. on treatment of the neutral complex [Cp*RhCl2PPh2(CF=CF2)],1a,with proton sponge,however,5a underwent dehydrofluorinative coupling to yield [h5,kP,kS-(C5Me4CH2CF=CF)PPh(C6H4SMe-2)RhCl]BF4,6. Other reactions,in particular addn. of HF across the vinyl bonds of 5,occurred leading to a mixt. of products. The cation of 3 underwent similar reactions. [on SciFinder (R)]

A review. The highlights of the year 2005 literature include the discovery of new supramol. halogen bonding motifs,an efficient 1-step synthesis of RIF2 and RI(OAc)2 compds. using Selectfluor,and new perspectives on the fluxional behavior of XeF6. [on SciFinder (R)]

The direct fluorination of intimately mixed Nb and Ta powders gives a range of mixed-metal pentafluorides [NbxTa4-xF20](x = 1,2,3) as discreet species isostructural with Ta pentafluoride (x = 0). The crystal structures are indistinguishable by x-ray crystallog. Ta4F20 crystallizes in the monoclinic space group C2/m with a 9.5462(13),b 14.3678(19),c 5.0174(7) .ANG.,b 97.086(2) Deg,Z = 2. The geometry about the Ta atom is distorted octahedral with 2 short and 2 slightly longer Ta-Fterminal,and 2 Ta-Fbridging distances. The angles at the bridging F atoms are 172.9(5) Deg.

The fluoro-alkynyl phenyl-and ferrocenylmercury compds. RHgC.tplbond.CCF3 (1,2; R = Ph,Fc) were prepd. by alkynylation of the corresponding chlorides RHgCl and LiC.tplbond.CCF3. The acetylides 1 and 2 are the first examples of fluorinated alkynylmercury compds. to be studied crystallog. The crystal structures of 1 and 2 have revealed the presence of appreciable mercury-centered intermol. interactions in the extended structures,including an apparent mercurophilic interaction. [on SciFinder (R)]

A review is presented on the 2004 literature on the elemental halogens and noble gases and compds. contg. these elements in their pos. oxidn. states. Many of the highlights in halogen chem. this year arise from applications of halogen-contg. materials. In particular,halogen bonding has moved from being an area of essentially academic interest to a topic with an ever-increasing range of applications. Thus,the shortest N...I halogen bond to date is reported and the use of halogen bonding to control and direct both architecture and chem. was described. For the noble gases,the first metal ion homoleptically coordinated to XeF2 ligands is reported and the application of noble gas compds. as novel oxidizing agents resulted in the first structurally characterized CX3+ (X = Cl,Br) systems. [on SciFinder (R)]

The reactions of the fluorovinyl-substituted phosphines PPh2(CF:CF2) and PPh2(CCl:CF2),with K2PtX4 (X = Br,I) were studied. The resulting complexes were characterized by a combination of 19F and 31P1H NMR,IR and Raman spectroscopy. The reactions of these phosphines with K2PtBr4 yield monomeric cis-[PtBr2PPh2(CF:CF2)2](1) and trans-[PtBr2PPh2(CCl:CF2)2](2),resp.,while the reactions with K2PtI4 yield both monomeric trans-[PtI2PPh2(CX:CF2)2],X = F (3),Cl (4),and dimeric [PtI(m-I)PPh2(CX:CF2)]2,X = F (5),Cl (6). The dimers 5 and 6 represent the 1st crystallog. characterized Pt(II) iodide-bridged phosphine complexes,and both adopt the sym.-trans structure.

Group 14 1-chloro-2,2-difluorovinyl compds. Ph3E(CCl:CF2) (E = Ge,Sn,Pb) were prepd. in 61-76%yields by using the low temp.-reactions of 1-chloro-2,2-difluorovinyllithium (LiCCl:CF2),generated in situ from CF3CH2Cl (HCFC-133a) and BuLi,with Ph3GeBr,Ph3SnCl and Ph3PbCl,resp. These new materials were fully characterized,including for E = Ge and Sn,by single crystal x-ray studies. This is the 1st time that any main-group 1-chloro-2,2-difluorovinyl compds. were crystallog. studied. [on SciFinder (R)]

A review. Highlights for 2003 in halogen chem. revolve around bromine-the discovery of a 2-dimensional Br-based network points to catenation on a scale previously seen only for iodine,and the first example of a bromane is reported. For the noble gases many new compds. were prepd.,most significantly,a stable,isolable,alkynylxenon(II) compd.,and the first example of a Hg-Xe complex. While using the matrix isolation technique the first org. mol. contg. Kr was generated. [on SciFinder (R)]

The 1st perfluorovinyl alkyl-contg. phosphines PR2(CF:CF2) (R = Et,iPr,Cy) are reported. The reactivity of these air-and moisture-stable materials was explored,both at the P center and at the fluorovinyl moiety. When PR2(CX:CF2) (X = F,Cl) is reacted with LiAlH4 a mixt. of PR2(CX:CFH) isomers and other defluorinated materials are produced,but the reaction with LiAlH(OBut)3 affords the single products Z-PR2(CF:CFH) or E-PR2(CCl:CFH),resp.,in high yields. Reaction of the fluorovinyl alkyl phosphines with H2O2,elemental S or Se yields fluorovinyl-contg. phosphine oxides,sulfides and selenides,resp. The phosphine sulfide iPr2P(S)(CF:CF2) is the 1st perfluorovinyl P(v) compd. to be characterized crystallog. and it exhibits an unusually short [1.9358(9) .ANG.]P:S bond. Reaction of fluorovinyl phosphines with XeF2 results in compds. F2PR2(CF:CF2),identified from multinuclear NMR studies. These compds. decomp. in the presence of moisture to yield the resp. phosphine oxides. Reaction of OPPh2(CF:CF2) with Br2 results in Br addn. across the double bond to give OPPh2(CFBrCF2Br). [on SciFinder (R)]

The first early-transition-metal 1-chloro-2,2-difluorovinyl complexes [Cp2TiXn(CCldCF2)2-n] (X ) Cl, F; n ) 0, 1) have been synthesized by the low-temperature reaction of Cp2TiX2 (X ) Cl, F) with (1-chloro-2,2-difluorovinyl)lithium, generated in situ from HCFC-133a (CF3- CH2Cl) and n-butyllithium. The complexes have been characterized by spectroscopy and, in the case of [Cp2TiCl(CCldCF2)], by single crystal X-ray diffraction, making this the first structurally characterized titanium-based fluorovinyl compound. The marked solution-phase instability of these materials has been explored in an attempt to identify key characteristics that might lead to stabilized systems. To this end, syntheses of the compounds [Cp*2TiFn-(CFdCF2)2-n] (n ) 0, 1) and [Cp2TiMe(CCldCF2)] have been reported and their stabilities investigated further. In the case of [Cp2TiMe(CCldCF2)], this has led to the spectroscopic characterization of the ?-complex [Cp2TiMe(?2-CF2dCClH)] as an intermediate in the solution-phase decomposition pathway.

Lithiation of HFC-245fa with BuLi in Et2O at-10 Deg followed by silylation with Ph3SiCl gave 85%Ph3SiC.tplbond.CCF3. Lithiation of Ph3SiC.tplbond.CCF3 with t-BuLi in Et2O followed by quenching the reaction mixt. with MeOH gave a mixt. of (Z)-Ph3SiCH:C(t-Bu)CF3,(E)-Ph3SiCH:C(t-Bu)CF3 (I),and title difluorocyclopropene II (E = Si). Similar lithiation of Ph3CC.tplbond.CCF3 with t-BuLi in Et2O followed by quenching with MeOH gave II (E = C). The crystal structure of I and II (E = Si) were detd. by x-ray crystal structure detn. and results were discussed via B3LYP DFT calcns.

Reaction of 1,1,1,3,3-pentafluoropropane (CF3CH2CF2H,HFC-245fa) with 3 equiv of n-butyllithium at-10 DegC leads to the generation of trifluoropropynyllithium in excellent yields. This reagent reacts readily with a range of group 14 electrophiles R4-nEXn (R = Ph,Et; E = C,Si,Ge,Sn,Pb; X = Cl,Br) to yield the organometalloid trifluoropropynyl compds. R4-nE(C.tplbond.CCF3)n. Three of these compds.,Ph3EC.tplbond.CCF3 (E = C,Si,Ge),have been crystallog. characterized,representing the first such study of these materials. The silane Ph3SiC.tplbond.CCF3 has been derivatized by reaction with LiAlH4 and a range of organolithium reagents (RLi,R = n-Bu,Ph,t-Bu) to afford a new series of b-CF3-substituted vinylsilanes of the type Ph3SiCH:C(CF3)R,with predominantly E geometry at the double bond. In the cases R = n-Bu,t-Bu,and Ph,these materials have been crystallog. characterized. Addnl.,a remarkably facile cyclization pathway for Ph3SiC.tplbond.CCF3,initiated by t-BuLi,that yields the resp. gem-difluorocyclopropene has been explored and is described in detail,along with its extension to a no. of other systems.

Crystals of the title compd. are orthorhombic,space group P212121,with a 7.1159(6),b 10.7627(11),c 12.1055(10) .ANG.; Z = 4,dc = 1.781; R = 0.056. Rw(F2) = 0.097 for 2071 reflections. It adopts a classic piano-stool structure,with the Cr(CO)3 tripod assuming a syn-eclipsed conformation relative to the arene ring (j = 2.0 Deg). The extended structure is dominated by intermol. p...H interactions (H...ring centroid 2.94 .ANG.) and nonclassical H bonds between carbonyl and arene moieties (O...H 2.50-2.58 .ANG.).

A review of the 2002 literature for elemental halogens and the noble gases and compds. contg. these elements in their pos. oxidn. states. Forty years after the isolation of the 1st noble-gas compd. there was somewhat of a renaissance in this area with,this year,four new Au-Xe compds. being reported and,using matrix techniques,HKrF and Xe-U compds. being formed and stabilized.

A review is given of the year 2001 literature for the elemental halogens and the noble gases and compds. contg. these elements in pos. oxidn. states.

A novel synthetic route to organic, inorganic and organometallic systems containing the trifluoropropynyl moiety utilises Hydrofluorocarbon 245fa (1,1,1,3,3-pentafluoropropane, CF3CH2CF2H) as a convenient synthon. Mild conditions are employed in an expedient and economical one-pot procedure, based on the intermediacy of trifluoropropynyllithium.

The group 14 trifluorovinyl compds. Ph3ECF:CF2 (E = Ge,Sn,Pb) were prepd. in high yield by the low-temp. reaction of the triphenylelement halide with trifluorovinyllithium,generated from tetrafluoroethane (CF3CH2F,HFC-134a) and 2 equiv of n-butyllithium. The x-ray crystal structures of these materials was obtained,so affording the first structural series for such species. Subsequent reaction of Ph3GeCF:CF2 with LiAlH4 and a range of organolithium reagents led to prepn. of the 1,2-difluorovinylgermanes Ph3GeCF:CFR (R = H,Me,n-Bu,t-Bu,Ph). Multinuclear NMR spectroscopic and X-ray crystallog. studies of these compds. showed the exclusive trans-geometry of the 1,2-difluorovinyl moiety.

A review of the annual advances made in halogen and noble gas chemistry.

The reaction of the HFC-replacements CF3CH2F (HFC-134a) and CF3CH2Cl (HCFC-133a) with two equiv. of butyllithium generates,in high yield,the fluorovinyllithium reagents CF2:CFLi and CF2:CClLi,resp. These Li reagents were used to synthesize fluorovinyl-contg. transition metal and main-group compds. in good yields. The resulting compds. may themselves then be used as stable transfer reagents. The synthesis of new fluorovinyl-contg. organometallic complexes,fluorovinyl-contg. phosphine ligands RnP(CX:CF2)3-n (n = 1,2; X=Cl,F) and their complexes is reported. The single crystal x-ray structures of [Fe(h5-C5H5)(CO)2(CCl:CF2)],cis-[PtBr2PEt2(CF:CF2)2]and trans-[PtCl2PPh2(CCl:CF2)2]are reported. [on SciFinder (R)]

The title compd.,N,N'-difluoro-N,N'-ethylenedi-p-toluenesulfonamide,C16H18F2N2O4S2.CHCl3,is a novel stable compd. of the N-F class of reagents contg. two R2N-F functionalities. The compd.,as the CHCl3 solvate,is the 1st such bis(N-F) compd. to be structurally characterized. It adopts a solid-state structure in which the two arom. rings are antiperiplanar and a combination of weak C-H...F and C-H...O H bonds [distances and angles range from 3.265(4) to 3.439(4) .ANG. and 150 to 170 Deg,resp.]and p-stacking between the rings of different mols. (sepns. of 3.717 and 3.926 .ANG.) results in a solid-state structure contg. well defined channels in which CHCl3 solvent mols. are located. The N-F distances are 1.428(3) and 1.433(3) .ANG.. Crystallog. data are given.

The one-pot reaction of the CFC replacement 1-chloro-2,2,2-trifluoroethane (CF3CH2Cl,HCFC-133a) with two equiv. of butyllithium in di-Et ether at-78 Deg followed by the addn. of main group or transition metal halides results in good yields of the metal-chlorodifluorovinyl-contg. compds. R3Sn(CCl:CF2) R = Me,Et,Bu,Sn(CCl:CF2)4,Sb(CCl:CF2)3,Hg(CCl:CF2)nCl(2-n) (n = 1,2),trans-[Ni(CCl:CF2)2(PBu3)2],trans-[Pd(CCl:CF2)2(PBu3)2]and [Au(CCl:CF2)(PPh3)]. The mol. structures of Hg(CCl:CF2)Cl,trans-[Pd(CCl:CF2)2(Bu3P)2]and [Au(CCl:CF2)(PPh3)]have been obtained from single crystal data; these are the first such structural data to be reported for any chlorodifluorovinyl-contg. organometallic complexes. The mol. structure of [Au(CF:CF2)(PPh3)],which was prepd. using a similar method based on CF3CH2F (HFC-134a),is also reported and compared with that of the chlorodifluorovinyl analog. [on SciFinder (R)]

This review,with 78 refs.,describes the historically important routes to fluorovinyl organometallic species M-(CX:CX2),where M is a main-group or transition-metal element and one,or more,of the substituent atoms,X,is F,the others being either other halogens,or H. A no. of newer synthetic methods are described which gave a wider range of examples of such compds. The structure,spectroscopy,properties,reactivity and future prospects for this class of compds. are described.

Reaction of perfluorovinyllithium,derived from CF3CH2F,with chloro-substituted phosphines generated perfluorovinylphosphines PPhm(CF:CF2)n and P(CF:CF2)nClm (n + m = 3) in high yields. A low-temp. crystal structure detn. of the air-and moisture-stable compd. PPh(CF=CF2)2 provided the 1st reported structural data for any perfluorovinyl-contg. material. There is considerable variation in the C-F bond distances [1.310(4),1.321(4),1.353(3) .ANG.]within the perfluorovinyl group in the phosphine. The coordination chem. of these ligands was studied via the synthesis of examples of late transition metal complexes. The results of single crystal structural detns. of cis-[PtCl2PPh2(CF:CF2)2]and [AuCl[PPh2(CF:CF2)]2].0.5CH2Cl2 are reported. In both of these mols. short metal-P distances [d(Pt-P)av = 2.231(3) and d(Au-P)av = 2.217(2) .ANG.]are obsd. compared with typical distances for similar phosphine complexes. A comparison of the electronic properties of these ligands with those of other phosphines,halophosphines and phosphites was made from a spectroscopic study of the carbonyl stretching frequencies of [Mo(CO)5PPhm(CF:CF2)n](n + m = 3).

A new route to perfluorovinyl compds.,recently reported by the authors,was used to prep. the 1st examples of early transition metal complexes Cp2M(CF:CF2)nX2-n (Cp: h5-C5H5-; M = Ti,Zr; X = Cl or F). These compds. were obtained in high yield from the two-stage,1-pot,reaction of HFC-134a (CF3CH2F) with two equiv. of BuLi,followed by addn. of Cp2MX2 (M = Ti,Zr,X = F,Cl). For two of the Ti-contg. compds. Ti K-edge EXAFS data were recorded from which distances for the Ti-C bond of the perfluorovinyl group of 2.033(12) and 2.050(18) .ANG. in Cp2Ti(CF:CF2)2 and Cp2Ti(CF:CF2)F were obtained. This is the 1st report of structural data for any perfluorovinyl organometallic compd.,and the distances obtained are consistent with the perfluorovinyl group binding in a simple sigma fashion. [on SciFinder (R)]

The low-temp. reaction between 2 equiv of (perfluorovinyl)lithium,derived from CF3CH2F and butyllithium,and Hg(II) chloride results in high yields of Hg(CF:CF2)2. Complete characterization of the air-and moisture-stable liq. product is afforded by multinuclear (13C,19F,199Hg) NMR studies. Crystals of [triclinic,space group P.hivin.1; a 4.956(4),b 5.733(4),c 6.394(4) .ANG.; a 104.57(5),b 109.32(6),g 107.16(6) Deg; Z = 1]were obtained by slow cooling; an x-ray structural detn. at 110 K represents the 1st such report for a (perfluorovinyl)metal complex. The Hg is coordinated linearly [r(Hg-C) = 1.998(5) .ANG.],and p-stacking of the perfluorovinyl groups is obsd. There is considerable variation in the C-F bond distances [1.286(6),1.312(6),1.362(6) .ANG.]within each perfluorovinyl group. Structural data for the vapor-phase species were obtained by anal. of the electron-diffraction pattern. There appears to be free rotation of the perfluorovinyl groups around the Hg-C bonds,a significantly longer Hg-C distance [2.054(3) .ANG.],and a similar,but smaller,variation in the C-F bond lengths. Theor. optimization of the geometry at the MP2/DZP level predicts a shallow potential-energy min. when the two perfluorovinyl groups are nearly perpendicular [F(C:C...C:C) = 98.2 Deg]to one another. Anal. of the bonding in the mol. suggests that no significant d(Hg)->p*(C:C) interaction is present. [on SciFinder (R)]

The reactions of mild fluorinating agents such as HF,IF5,IF7 and XeF2 with transition metal oxo-anions were used to provide new synthetic routes to MnO3F,ReO3F,CrO2F2,MoO2F2 and WO2F2.

The crystal and mol. structures of [Au2S2CN(C2H4OMe)22],[Au(PPh3)(SCH2CO2H)],[Au(PPh3)(SCMe2-CO2H)]and [Au(PPh3)(SCH2CO2Me)]were detd. All compds. contain an approx. linear primary coordination sphere of ligands about the Au atom,but they differ markedly in their type of intermol. interaction. In [Au2S2CN(C2H4OMe)22]the supramol. array is dominated by an almost linear,polymeric backbone of Au atoms with alternate Au-Au contacts of 2,7902(6) (intramol.) and 3.1572(7) .ANG. (intermol.),whereas in [Au(PPh3)(SCH2CO2H)]dimers assocd. through long Au-S contacts of 3.131(2) .ANG. are held together in a polymeric chain by H bonding between neighboring carboxylic acid residues. The increased steric bulk of the thiolate ligand in [Au(PPh3)(SCMe2CO2H)]caused by the Me groups on the a-C atom precludesassocn. of the Au centers,but H bonding between carboxylates as in the SCH2CO2H compd. causes dimerization. [Au(PPh3)(SCH2CO2Me)]exists as a monomer with no evidence of weak intermol. interactions. Anal. of ambient-temp. EXAFS (extended x-ray absorption fine structure) measurements on solid samples of the 1st two compds. yield Au-Au sepns. of 2.775(2) and 3.271(6) .ANG. and 4.188(15) .ANG.,resp. Au-S sepns. of 2.290(1) and 3.532(8) and of 2.329(4) and 3.124(19) .ANG.,resp.,are also in good agreement with x-ray data. [on SciFinder (R)]

The 1-pot reaction of the chlorofluorocarbon replacement,CF3CFH2 (HFC-134a),with 2 equiv of butyllithium in Et2O at-78 Deg gave intermediate perfluorovinyllithium reagent which when followed by the addn. of main-group or transition-metal halides results in good yields of the corresponding metal-perfluorovinyl compds. of high purity. E.g.,F2C:CF-Li+ reagent (prepd. as above) reacted with HgCl2 in 2:1 ratio and allowed to warm to room temp. to give Hg(CF:CF2)2 in 90%yield. [on SciFinder (R)]

The compd. WSF4 was synthesized in one step by the reaction of WF6 with (Me3Si)2S in soln. at ambient temps. Soln.-phase structural data were obtained for the first time for it and related W chalcogenide tetrahalides via a W L(III)_edge EXAFS (extended x-ray absorption fine structure) study. WOF4,WOCl4 and WSF4 in MeCN or CH2Cl2 soln. are monomeric. For WSF4 anal. of the EXAFS data yielded bond lengths of 2.026(8) (W=S) and 1.863(3) .ANG. (W-F). The W=S bond length is shorter than previously detd.,by gas-phase electron diffraction,but is more consistent with that found in related structures. [on SciFinder (R)]

Fluorination of pure [60]fullerene and [70]fullerene by fluorine gas shows batch variation,and is accompanied by color changes as fluorine slowly penetrates the fullerene lattice. Attempted partial fluorination produces a mixt. of highly and unfluorinated material due to this slow penetration. [60]Fullerene undergoes fluorination more slowly than [70]fullerene,due to better packing of the crystal lattice in the former,and this explains why [60]fullerene contaminated with [70]fullerene is fluorinated faster than pure [60]fullerene. The NMR spectrum of fluorinated [70]fullerene shows a no. of singlets between d-151.2 and-153.65,indicating the formation of a mixt. of derivs. each possessing high symmetry. The IR of fluorinated [70]fullereneshows a broad band at 1112 cm-1. The mass spectra of fluorinated [60]-and [70]-fullerenes reveals species contg. up to eleven and sixteen oxygen atoms in each case (deposition from methanol). The max. site occupancies of species detected (assuming that oxygen is present as the epoxide) are 68 and 70,resp. Methylene-and (after reaction with methanol) trifluoromethyl-contg. species are also evident in the mass spectrum of fluorinated [60]fullerene; corresponding species are not found in fluorinated [70]fullerene. The high level of epoxide formation with the fluorofullerenes indicates that the tendency for fullerenes generally to form epoxides derives from the strong electron withdrawal by the cages. [on SciFinder (R)]

Tetrairidium dodecacarbonyl reacted with XeF2 in anhyd. HF soln. at low temps. via sequential fluorination yielding initially fac-and mer-[IrF3(CO)3]and finally IrF5. The novel 18-electron Ir carbonyl fluorides were characterized by a combination of IR spectroscopy,13C,13C-19F and 19F NMR spectroscopies and EXAFS spectroscopy studies in HF soln.

The metal L(III)-edge EXAFS for the 5d transition metal hexafluorides in anhyd. HF soln. have been recorded for the first time. In addn. to the first coordination sphere,addnl. features in the EXAFS have been satisfactorily modelled resulting from the first HF solvation spheres. These data indicate that significant order exists in HF soln. and offer the first est. of the occupation no. of the first solvation sphere for this solvent. [on SciFinder (R)]

Reaction of fluorinated C60 (C60Fn,values of n all even and up to at least 54) with water produces numerous species C60FxOy (x all even) with up to eighteen oxygen atoms attached to the cage,the max. values of x + 2y being 52-58. [on SciFinder (R)]

Monomeric mol. ruthenium oxide tetrafluoride,prepd. by the reaction of RuF5 with glass at c. 300 DegC,has been characterized by mass spectrometry and matrix-isolation IR spectroscopy. RuOF4 exhibits C4v symmetry,in common with all the known transition-metal oxide fluorides,with the O-Ru-F angle calcd. to be equal to 110 +-6 Deg.

Os LIII edge EXAFS data were obtained for OsO3F2,K[OsO3F3],and Cs2[OsO4F2]and refined.

IR and UV-visible spectra are reported for the prepd. unstable K[RhF6]and K[PtF6]salts. Assignment of the UV-visible spectra by the strong-field model and optical-electronegativity approach allows coptMV to be calcd. for Rh and Pt as 3.1 and 3.25,resp.

Metal K-edge extended x-ray absorption fine structure data obtained for MoF6,RuF6 and RhF6 as solids at 10 K were refined to give d(M-F) = 1.81 (Mo),1.83 (Ru) and 1.84 .ANG. (Rh). Corresponding values for the powd. fluoroanions at room temp. are ca. 1.85 .ANG. for K[MF6](M = Ru or Rh) and 1.90-1.93 .ANG. for K2[MF6](M = Ru,Rh or Pd). The value of d(Rh-Cl) in Cs2[RhCl6]is 2.31 .ANG.. The results are compared with previous data on the 5d analogs and with x-ray crystallog. data.

Metal Llll-edge EXAFS data were collected for WF6,ReF6,OsF6,IrF6 and PtF6 as solids at 10 K,and refined to give M-F bond lengths which lie in the range 1.81-1.83 .ANG.. Similar data were obtained for the related hexafluoroanions K2[MF6]and K[MF6](M = Os,Ir or Pt) as powd. solids at room temp.,which give M-F bond lengths of 1.92-1.93 and 1.88-1.91 .ANG.,resp.

IR spectroscopy shows that CrO2F2 and MnO3F are monomeric in the solid state. Metal K-edge EXAFS data were obtained from the solids at 10 K and refined to give d(Cr-O) = 1.55,d(Cr-F) = 1.71,d(Mn-O) = 1.59,and d(Mn-F) = 1.72 .ANG.. [on SciFinder (R)]

Solid samples of M2SeO4 and M2SeO3 (M = alkali metal) were heated in vacuo,and the vaporization products studied using a combination of mass spectral and matrix isolation IR techniques. Although some decompn. was obsd.,evidence was obtained for the existence of the ternary mol. salts M2SeO4 and M2SeO3 (M = Na,K,Rb,Cs) and the novel Se(III) species MSeO2. The mol. symmetries are identified as D2d,Cs,and C2v,resp.,based on vibrational selection rules,and the various O-Se-O bond angles in these species are estd. from Se isotope shifts and relative band intensities.

MnO3F,ReO3F,ReO2F3,ReOF5 and ReOF4 have been isolated as mol. species in inert-gas matrixes at low temps.,and studied by IR and UV/visible spectroscopies. In particular,the electronic spectra are described and the principal charge transfer bands assigned using the optical electronegativity model. This suggested that a new value for copt (F-) of 3.6 is appropriate for transition metal oxide fluorides.

Samples of the solids NbCl5,NbBr5,TaCl5,TaBr5,ReCl5,ReBr5 and OsCl5 have been vaporized in vacuo,and the products characterized by mass spectrometry and IR and UV/Vis spectroscopy in low temp. argon and nitrogen matrixes. In particular it is shown that vaporization of the d0 species leads to the prodn. of simple monomers,which adopt a square-pyramidal shape in nitrogen and a variety of conformers in argon. Rhenium pentachloride vaporizes as a monomer which exhibits D3h symmetry in both argon and nitrogen,but ReBr5 and OsCl5 decomp.,the former to yield mol. Re3Br9. [on SciFinder (R)]

Matrix-isolation studies were performed on MoCl5 prepd. by 3 routes. In a N matrix,prominent IR bands were obsd. at .apprx.473 and 408 cm.hivin.1,which on the basis of isotope studies are assigned as the A1(axial) and E Mo-Cl stretching modes of monomeric MoCl5 (C4v). Ar matrixes yielded essentially the same spectroscopic features. Corresponding UV-visible spectra were obtained and assigned on the basis of a square-pyramidal geometry. MoCl6 was not obtained from reaction of MoO3 with SOCl2 at various conditions.

New syntheses of RuF6 and RhF6 are reported involving fluorination of the corresponding pentafluorides at 220 Deg and 30 atm. IR spectra for RuF6 and RhF6 isolated in nitrogen and argon matrixes at 12 K were recorded and assigned. The UV-visible spectra in nitrogen matrixes are complex contg. both fluorine-to-metal charge-transfer and d-d transitions. Assignments for the main features are proposed.

A novel exptl. approach is described for characterizing fission product vapors over a wide range of temps. and pressures. The combined techniques of matrix isolation-IR spectroscopy and mass spectrometry were used to est. the identities of typical high-temp. vapor species,and their mol. shapes and fundamental vibration frequencies. The app. used for these studies is described,and some recent results on simulant fission-product chem. involving the elements Cs,Te,Sn,and In are presented. The relevance of this work to the thermodn. modeling of such systems is discussed.

WCl5 was heated in high vacuum,and the vapor species isolated in inert matrixes at .apprx.12 K. Subsequent IR spectra showed intense features at 410 and 365 cm-1,which were assigned as the A2änd E'stretching modes,resp.,of monomeric D3h WCl5. Corresponding studies on WCl6 showed that monomeric WCl6 could similarly be isolated,and for this species,the UV-visible spectrum was obtained and analyzed. The vaporization of WBr5.3 yielded a new spectroscopic feature in the matrix IR spectrum at .apprx.305 cm-1,which was assigned to WBr6. At higher temps.,the vaporization of the solid WBr5 resulted in bands at 280 and 245 cm-1,which were assigned as the A2"and E'stretching modes in D3h WBr5.

The mol. species present in the vapor above heated SeO3 and above mixts. of H2SeO4/P2O5 were investigated by matrix isolation IR spectroscopy and mass spectrometry. The major species from SeO3 was (SeO3)4,but H2SeO4/P2O5 mixts. yielded significant proportions of monomeric SeO3. This mol. is characterized for the 1st time by IR spectroscopy; and in Ar matrixes,has prominent IR fundamentals at .apprx.999 cm-1 (E'Se=O stretch) and .apprx.356 cm-1 (A2"bend).

The vapor species produced on heating As2O5 in vacuo were isolated in low-temp. matrixes and examd. by IR spectroscopy. Detailed studies reveal the existence of As4O6 and 4 higher oxides As4O7,As4O8,As4O9,and As4O10 which are characterized for the 1st time as stable mol. entities. Band assignments are proposed for several of the more intense absorptions,and the effects of 18O enrichment in the terminal As:O stretching region are interpreted on the basis of a restricted force-field anal. [on SciFinder (R)]