A comparison of the ligating properties of the mixed P/O- and P/S-donor ligands Ph2P(CH2)(2)O(CH2)(2)O(CH2)(2)PPh2 and Ph2P(CH2)(2)S(CH2)(2)S(CH2)(2)PPh2 with Group 6 and 7 carbonyls

摘要

M(CO)(4)(nbd)] (M = Cr or Mo) react with L-1 (Ph2P(CH2)(2)O(CH2)(2)O(CH2)(2)PPh2) to give the trans-[Cr(CO)(4)(L-1)] and cis-[Mo(CO)(4)(L-1)] respectively, both of which show coordination of L-1 through the P atoms only, giving 11-membered ring metallocyclic complexes. The crystal structure of [MO(CO)(4)(L-1)] confirms the cis-geometry of the product. The cis-[W(CO)(4)(L-1)] is obtained similarly from [W(CO)(4)(TMPA)]. Prolonged reaction of [MnCl(CO)(5)] with L-1 affords mer-trans-[MnCl(CO)(3)(L-1)], with L-1 functioning as a trans chelate via the phosphine functions. The kinetic product fac-[MnCl(CO)(3)(L-1)] is obtained when short reaction times are used. In contrast, [ReBr(CO)(5)] reacts with L-1 to give [ReBr(CO)(3)(L-1)] as a mixture of geometric isomers. Both 1:1 and 2:1 M:L-2 (L-2 = Ph2P(CH2)(2)S(CH2)(2)S(CH2)(2)PPh2) may be obtained for M = Mn(I) or Mn(0). The [MnCl(CO)(3)(L-2)] exists in solution as the fac isomer with L-2 functioning as a bidentate P,S-donor ligand giving a five-membered chelate ring and with the remaining thioether and phosphine functions uncoordinated. Addition of a further equivalent of [MnCl(CO)(5)] affords the binuclear fac-[{MnCl(CO)(3)}(mu(2)-L-2)], with symmetrical P,S-chelation to each metal centre. Similar behaviour is seen for Mo, thus cis-[{Mo(CO)(4)}(2)(mu(2)-L-2)] involves P,S-chelation to each Mo(0) ion. The related 1:1 species cis-[Mo(CO)(4)(L-2)] exists as a mixture of two compounds each with bidentate L-2 coordination, the P-2-chelate (11-membered ring metallocycle) and P,S-coordinated (five-membered chelate ring) species. The new compounds are characterised by microanalyses, IR, H-1-, C-13{H-1}-, P-31{H-1}-,Mn-55-NMR spectroscopy and mass spectrometry as appropriate. The different ligating properties of the related compounds L-1 and L-2 are discussed. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 17