Reactions of Re2Cl4(dppm)2 with carbon monoxide that proceed with retention of the metal-metal bond: synthesis of Re2Cl4(dppm)2(CO)n (n = 1, 2) and the structural characterization of Cl2Re(.mu.-Cl)(.mu.-CO)(.mu.-dppm)2ReCl(CO)

Reactions of the Dirhenium(II) Complexes Re2X4(μ-dppm)2 (X = Cl, Br; dppm = Ph2PCH2PPh2) with Isocyanides. 18.1 The Isolation and Characterization of Isomers of the [Re2Cl2(μ-dppm)2(CO)(CNXyl)3]2+ Cation and Its Monocationic and Neutral Congeners

“…Starting Materials and General Procedures. The compounds Re 2 Cl 4 (μ-dppm) 2 (CO) ( 1 ), Re 2 Cl 4 (μ-dppm) 2 (CO)(CNXyl) ( 2 ), [Re 2 Cl 3 (μ-dppm) 2 (CO)(CNXyl) 2 ]O 3 SCF 3 ( 3 ), [Re 2 Cl 3 (μ-dppm) 2 (CO)(CNXyl)]O 3 SCF 3 , TlO 3 SCF 3 , and [(η 5 -C 5 H 5 ) 2 Fe]PF 6 were prepared by standard literature procedures. Samples of 2,6-dimethylphenyl isocyanide (XylNC) were purchased from Fluka Chemical Corp., TlPF 6 and NOPF 6 from Strem Chemicals, and (η 5 -C 5 H 5 ) 2 Co from Aldrich Chemical Co.…”

Reactions of the Dirhenium(II) Complexes Re2X4(μ-dppm)2 (X = Cl, Br; dppm = Ph2PCH2PPh2) with Isocyanides. 19.1 Studies of the Reactions of Five Structural Isomers of Re2Cl2(μ-dppm)2(CO)(CNXyl)3 That Lead to the Dirhenium(I) Complexes [Re2(μ-Cl)(μ-CO)(μ-dppm)2(CNXyl)4]O3SCF3 and [Re2Cl(μ-dppm)2(CO)(CNXyl)3<

“…The incorporation of up to four π-acceptor ligands about the coordination sphere of the [Re 2 (μ-dppm) 2 ] 4+ unit (dppm = Ph 2 PCH 2 PPh 2 ) has been accomplished − in the following reaction sequence which utilizes the triply bonded dirhenium(II) complex Re 2 Cl 4 (μ-dppm) 2 as the starting material: Several of the analogous bromo complexes have also been isolated and characterized. ,,− …”

“…These systems are noteworthy for the remarkably large number of stable structural isomers that can be isolated, the dependence of the Re−Re bond order on the structure of the isomer, and the rich reversible redox chemistry that many of these complexes possess. − For example, our most recent study 1,15 has led to the isolation of four structurally distinct, noninterconvertible isomers of the [Re 2 Cl 2 (μ-dppm) 2 (CO)(CNXyl) 3 ] 2+ cation, each of which exhibits reversible redox chemistry that leads in two instances to coupled redox/isomerization processes. In all, the [Re 2 Cl 2 (μ-dppm) 2 (CO)(CNXyl) 3 ] n+ species ( n = 2, 1, or 0) exist in seven structural variants, which possess Re−Re bond orders of 3, 2, 1.5, 1 or 0.…”

Reactions of the Dirhenium(II) Complexes Re2X4(μ-dppm)2 (X = Cl, Br; dppm = Ph2PCH2PPh2) with Isocyanides. 13.1 Identification of a New Structural Isomer of the Dirhenium Cation [Re2Cl3(μ-dppm)2(CO)(CNXyl)2]+ and Its Isomerization Behavior. Structural Characterization of (XylNC)ClRe(μ-Cl)(μ-CNXyl)(μ-dppm)2ReCl(CO)

“…The ability of the triply bonded dirhenium(II) synthons Re 2 X 4 (μ-dppm) 2 (X = Cl, Br; dppm = Ph 2 PCH 2 PPh 2 ) to react with carbon monoxide and organic isocyanides, with incorporation of up to three of these ligands into the coordination sphere of the dimetal unit, is well-established (see Table ). − In several instances, these complexes have been shown to exist as structural isomers. ,− ,, The scope of this chemistry is currently under investigation in our laboratory, a principle aim of which is to identify new classes and types of isomers in redox-active dimetal systems which contain metal−metal bonds.…”