Characterization of [Re2Cl3(mu-dppm)(2)(NCCH3)(2)][Cl] and [Re2Cl3(mu-dppm)(2)(NCC6H5)(2)][Cl]center dot 2CH(2)Cl(2) by X-ray crystallographic and two-dimensional NMR spectroscopic techniques

The complex Re2Cl6(P-n-Bu-3)(2) prepared in situ reacts with CH3CN to form a blue-green solution. Addition of the chelating phosphine bis(diphenyl-pho sphino)methane (dppm) results in the formation of the complex [Re2Cl3(mu-dp pm)(2)(NCCH3)(2)][Cl] (1) upon heating. The two acetonitrile molecules adop t a trans geometry on the rhenium center with the axially coordinated chlor ine. The analogous ii ans benzonitrile species [Re2Cl3(mu-dppm)(2)(NCC6H5)( 2)][Cl]. 2CH(2)Cl(2) (2) is synthesized under the same reaction conditions. The coupling constants of the AA'BB' P-31{H-1} NMR spectra of the compound s were elucidated from (31)p-(31)p homonuclear J-resolved NMR experiments. Additional characterization methods include (31)p{H-1} NMR Spetroscopy, UV- Yis spectroscopy, and X-ray crystallography.