Trifluoromethanesulfonate anion, ligand

Another approach, which permits introduction of anionic ligands of strong acids, is to react a complex containing coordinated chloride ion directly with an anhydrous strong acid, such as trifluoromethanesulfonic acid, in the total absence of any other solvent. One example, where HC1 is released as a covalent gas and leaves the anhydrous reaction mixture and the CF3SO3 anion enters the coordination sphere as an O-bound monodentate ligand, is reaction with chloropentaamminecobalt(III) chloride (6.19). 

Vahrenkamp and co-workers formed a number of chelate-stabilized ketone complexes with pyridylphenyl ketone. Octahedral complexes formed with a 2 1 ratio of ligand to zinc were formed with trifluoromethanesulfonate, chloride, and bromide anions. 1 1 reactions resulted in the formation of square pyramidal [ZnL2X]+ with X = Br, I, and a trigonal-bipyramidal dimer [L2Zn(NCS)2]2 with thiocyanate bridges.350... 

Acac = acetyacetonate BArf = tetra(3,5-bis(trifluorome-thyl)phenyl)borate anion bridge = 1,3-diisocyanopropane COD = cycloocta-1,5-diene COE = cyclooctene DFT = Density Functional Theory dimen = 2,1,8-diisocyanoment-hane DMAD = dimethylacetylene dicarboxylate DMSO = dimethylsulfoxide dpmp = bis(diphenylphosphinomethyl) phenylphosphine DPPB = l,4-bis(diphenylphosphino)but-ane DPPE = l,2-bis(diphenylphosphino)ethane DPPM = bis(diphenylphosphino)methane en= 1,2-diaminoethane hfac = hexafluoroacetylacetonate HFB = hexafluorobut-2-yne HOTf = trifluoromethanesulfonic acid (triflic acid) MLCT = Metal Ligand Charge Transfer MO/MM = Molecular Orbital/Molecular Mechanics NBD = bicyclo[2. 2.1]heptadiene OTf = trifluoromethanesulfonate (triflate) ion OTs = p-toluenesulfonate (tosylate) ion /j-anis = /7-MeOC6H4 pip = piperidine pn = 1,2-diaminopropane PPN+ = bis(triphenylphosphine)iminium cation p-to = p-MeCeUt pz = pyrazolate QM/MM = Quantum Mechan-ics/Molecular Mechanics TFB = tetrafluorobenzobarrelene TM4 = 2,5-diisocyano-2,5-dimethyIhexane tn = 1,3-diami-nopropane. 

Transition metal cations solvated by weakly coordinating solvents are useful precursors for a variety of nonaqueous synthetic applications. The dissociation of acetonitrile ligands opens up vacant coordination sites for catalysis, and allows transition metals to be introduced into extended arrays formed by condensation reactions with polydentate ligandsAlthough salts of homoleptic acetonitrile metal cations with tetrafluoroborate anions have been known since the 1960s, there has been no detailed description of the syntheses and characterization of these compounds. Likewise, there have been general descriptions of the syntheses of trifluoromethanesulfonate salts, but no specific outline for individual metals has been published. In this report, the syntheses of [M (CH3CN)x][BF4]2 (M = Cr,Mn,Fe,Co,Ni,Cu) and [M CHaCNlJlSOsCFsla (M = Mn,Fe,Co,Ni) are described. Two different methods are used to prepare tetrafluoroborate salts (1) the oxidation of metals with nitrosonium tetrafluoroborate, first described by Hathaway et al. and (2) the dehydration of aqueous tetrafluoroborate salts in a Soxhlet extractor with molecular sieves. The oxidation reaction is rapid, anhydrous, and recommended for smaller-scale preparations because of the relatively... 

Addition of a proton to a carbyne ligand may transform it into a carbene. The proton can be provided by an external source or by transfer from another ligand. Examples of the first land are provided by the addition of acids to complex 18 (see Scheme 7).l l The use of pyridinium salts yields more stable pyridine adducts. This reaction can be reversed by the addition of a strong base (see Section 2.6.2). When an acid containing a noncoordinating anion is used, e.g. trifluoromethanesulfonic add, cationic derivatives may be obtained, Depending on the nature of the coligands, the proton may preferentially add to another position in the molecule (see Section 2.6.2). 

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