Charge-transfer interactions between sulfur dioxide and group 8 half-sandwich complexes

Abstract

M ulliken-type charge-transfer complexes have been formed between basic half-sandwich compounds and SO, when [M(q5-C,R,)(CO),] (M = Rh or Ir; R, = Me,, H, or H,CF,), [Ir(q5-C,H,)(CO)(C,H,)]. and [M(q5-C,H,)(C,H,),] ( M = Co, Rh or Ir) are isolated in SO,-doped argon matrices at 20 K; the v ( C 0 ) bands of the complexes are shifted to high frequency of those of the precursor molecules and prominent charge-transfer bands are observed; the same species have been detected when the compounds [M(q5-C,Me,)(CO),] ( M = Rh or Ir) are embedded in polyethylene discs and treated with SO, at 213-298 K; the enthalpy of complexation of [Ir(q5-C,Me,)(CO),]with SO, is -13 f 3 k J mo1V.

Comparisons of Photoinduced Oxidative Addition of B−H, B−B, and Si−H Bonds at Rhodium(η5-cyclopentadienyl)phosphine Centers

“…The effect of an electron-withdrawing CF 3 group on the properties of metallocenes and methylated metallocenes was investigated by Gassman et al , Notably, the redox potential of [Fe(η 5 -C 5 H 4 CF 3 )(η 5 -C 5 H 5 )] is shifted by 0.64 V with respect to ferrocene. The C 5 H 4 CF 3 group also has a marked effect on the kinetics of substitution reactions of cyclopentadienyl rhodium dicarbonyls, but little effect on charge-transfer complexes with sulfur dioxide …”

Synthesis and Coordination Chemistry of Fluorinated Cyclopentadienyl Ligands

“…27 Diels–Alder dimerization is mentionable slow at room temperature with a half-life time of 30 d. 27 Subsequent deprotonation with TlOEt gave insoluble [Tl][C 5 (CF 3 )H 4 ] which rapidly decomposes at room temperature, but is sufficiently stable at –15 °C. 27 A series of transition-metal complexes could be prepared by subsequent halide abstraction reactions, e.g., with titanium, 27 29 manganese, 27 iron, 27 , cobalt, 27 30 rhodium, 27 31 32 iridium, 27 32 platinum, 33 or copper (Scheme 3 ). 34 The strongly electron-withdrawing character of the CF 3 -substituted cyclopentadienyl ligands is demonstrated by the redox potential of {Fe[C 5 (CF 3 )H 4 ] 2 } with E 1/2 = +0.64 V (in CH 2 Cl 2 vs. Fc).…”