Chromium and molybdenum pentacarbonyl complexes of phosphinocarbodithioates: synthesis, molecular structure and behaviour in RAFT polymerisation.

Molybdenum and chromium pentacarbonyldiphenylphosphinocarbodithioate complexes have been prepared in a one-pot reaction from the corresponding metallocarbonyldiphenylphosphine. The complexes have been characterised by IR, (1)H, (31)P and (13)C NMR spectroscopies and by mass spectrometry. The solid-state structures of [Cr(CO)(5){PPh(2)CS(2)CH(Ph)CH(3)}] (1) and [Mo(CO)(5){PPh(2)CS(2)CH(Ph)CH(3)}] (2) are reported. Compounds 1 and 2 are isostructural and crystallise in the triclinic P1 space group. These new organometallic compounds are highly efficient reversible chain-transfer agents for reversible addition-fragmentation chain-transfer (RAFT) polymerisation of styrene (St) and n-butyl acrylate (nBA), with controlled number-average molar mass values and narrow dispersities (<1.2). The controlled character of the polymerisation was further exemplified by the synthesis of St and nBA diblock copolymers.