Models for organometallic polymers. Zigzag chains of tetrakis(acetate)dimolybdenum units linked by bis(dimethylphosphine)ethane and tetramethylethylenediamine ligands

Abstract

Infinite zigzag chains of Mo{sub 2}(O{sub 2}CCH{sub 3}){sub 4} units linked by the bidentate ligands 1,2-bis(dimethylphosphino)ethane (dmpe) and tetramethylethylenediamine (tmed) crystallize from solutions of Mo{sub 2}(O{sub 2}CCH{sub 3}){sub 4} (1) dissolved in the respective neat ligand. Single-crystal X-ray structures of the light yellow polymers {sub {infinity}}{sup 1}(Mo{sub 2}(O{sub 2}CCH{sub 3}){sub 4}(dmpe)) and (2) and {sub {infinity}}{sup 1}(Mo{sub 2}(O{sub 2}CCH{sub 3}){sub 4}(tmed)) (3) showed that the compounds were isostructural. Crystal structures for compounds 2 and 3 reported. The ligands dmpe and tmed are coordinated axially through weak Mo-L bonds to relatively unperturbed Mo{sub 2}(O{sub 2}CCH{sub 3}){sub 4} centers. The solid-state Raman spectrum of 3 reveals a small decrease in the Mo-Mo stretching frequency ({nu}{sub Mo-Mo} = 391 cm{sup {minus}1}) relative to 1 ({nu}{sub Mo-Mo} = 405 cm{sup {minus}1}). TGA and powder diffraction studies involving 3 showed that solid-state thermolysis results in the expulsion of tmed at 92{degree}C and the formation of crystalline 1. 25 refs., 3 figs., 6 tabs.