Chromium and Molybdenum Pentacarbonyl Complexes of Phosphinocarbodithioates: Synthesis, Molecular Structure and Behaviour in RAFT Polymerisation

Abstract

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.

Phosphinoyl and Thiophosphinoylcarbodithioates: Synthesis, Molecular Structure, and Application as New Efficient Mediators for RAFT Polymerization

“…Polymerizations are slower than with the Cr-RAFT and Mo-RAFT agents previously studied. [27] This is probably related to a more pronounced stability of the intermediate radicals with P-RAFT agents. The possibility of a small fraction of dead PSt chains resulting from irreversible termination of intermediate radicals [40] cannot be ruled out, and could contribute, together with classically terminated chains due to AIBN initiation; to the presence of a small but visible shoulder at around twice the molar mass of the main peak of the SEC chromatograms (Figure 3 b).…”

“…[26] At the beginning of our work, we first studied metallophosphorus-based compounds such as Group 6 metal pentacarbonyldiphenyl-phosphinocarbodithioates (M(CO) 5 PPh 2 CS 2 R, with M = W, Cr, Mo and R =ÀCH 2 CN, ÀCH(CH 3 )C 6 H 5 ) as mediators for the RAFT polymerization of St and n-butyl acrylate (nBA). [27] In parallel, Chen et al polymerized St and tert-butyl acrylate by using tungstenpentacarbonyl derivatives with benzyl and allyl as leaving R groups. [28] Our first results confirmed that these metallophosphorus-based compounds behave as efficient RAFT agents.…”

“…Interestingly, we demonstrated that the chain-transfer reactivity, thermal and chemical stability of phosphino RAFT agents and the resulting polymers could be easily monitored by 31 P NMR spectroscopy. [27] The next step was to study the influence of the direct environment around the phosphorus center by using ligands providing more versatile electronic effects. We report here the synthesis and studies in radical polymerization of phosphinoyl and thiophosphinoylcarbodithioates as new organophosphorus-based RAFT agents, namely P-RAFT.…”

Living Radical Polymerization by the RAFT Process – A Third Update

“…A [549] St [549] BA [549] St-b-BA [549] 288 S S P Mo CO OC CO OC CO A [549] St [549] BA [549] A See footnote A of Table 3.…”

Unexpected fragmentation of bis(triarylstannanethiocarbonyl)disulfides, formation and X-ray structure of triarylstannyl triarylstannanecarbodithioates

“…1.64 (2) 1.695 (4) The synthesized products could potentially be used in free radical transformations as reagents for radical reduction [19] or regulators in RAFT polymerization [20,21]. These features will be subject to future investigation.…”