Synthesis, characterization and structures of cyclic organorhodium complexes of the type [Rh{CH(SO2Ph)CH2CH2YR2-κC,κY}L2] (YR2 = PPh2, NMe2; L2 = diphosphine, cyclooctadiene)

Abstract

Reactions of dinuclear chloridorhodium(I) complexes [(RhL₂)₂(μ-Cl)₂] (L₂ = PP: Me₂P(CH₂)₂PMe₂, dmpe, 7a; Ph₂PCH₂PPh₂, dppm, 7b; Ph₂P(CH₂)₂PPh₂, dppe, 7c; Ph₂P(CH₂)₃PPh₂, dppp, 7d; L₂ = cycloocta-1,5-diene, cod, 5) with lithiated γ-phosphino- and γ-aminofunctionalized propyl phenyl sulfones (Li[CH(SO₂Ph)CH₂CH₂PPh₂], 2; Li[CH(SO₂Ph)CH₂CH₂NMe₂], 4) led to the formation of organorhodium inner complexes of the type [Rh{CH(SO₂Ph)CH₂CH₂PPh₂-κC,κP}(PP)] (8a–d), [Rh{CH(SO₂Ph)CH₂CH₂NMe₂-κC,κN}(PP)] (9a–d), [Rh{CH(SO₂Ph)CH₂CH₂PPh₂-κC,κP}(cod)]·LiCl (11·LiCl) and [Rh{CH(SO₂Ph)CH₂CH₂NMe₂-κC,κN}(cod)]·LiCl (12·LiCl), respectively. Single-crystal X-ray diffraction analysis of 9c·THF, 11 and 12 exhibited in all three compounds a distorted square planar coordination of the rhodium atoms having bidentately coordinated neutral co-ligands (cod, 11, 12; dppe, 9c) and anionic α-phenylsulfonyl γ-phosphinopropyl (κC,κP; 11) and γ-aminopropyl ligands (κC,κN; 12, 9c), thus being typical organorhodium inner complexes. Furthermore, organorhodium inner complexes of type 8 were obtained in reactions of the dinuclear chloridobridged rhodium complexes [(RhL₂)₂(μ-Cl)₂] (L₂ = PP, 7a–d; cod, 5; (C₂H₄)₂, 6) with the (non-lithiated) γ-phosphinofunctionalized propyl phenyl sulfone PhSO₂CH₂CH₂CH₂PPh₂ (1) resulting in the formation of complexes having the sulfone κP coordinated ([RhClL₂(Ph₂PCH₂CH₂CH₂SO₂Ph-κP)] (L₂ = PP, 10a–d; cod, 13; (C₂H₄)₂, 14) which were deprotonated (10a–d, 13) at the α-C atom with lithium diisopropyl amide (LDA) in a subsequent reaction. Single-crystal X-ray diffraction analysis of 10c (PP = dppe) revealed the expected square-planar coordination geometry of Rh. The identities of all rhodium complexes have been unambiguously proved by microanalyses and NMR spectroscopy (¹H, ¹³C, ³¹P).