Subvalent Group 14 metal compounds: Part 16. Synthesis, crystal structure and characterisation of some β-functionalised-alkyltin(II) complexes, SnR(X){R = C5H4N[C(SiMe3)2]-2; X = R, Cl or N(SiMe3)2}

Brian S. Jolly, Michael F. Lappert, Lutz M. Engelhardt, Allan H. White, Colin L. Raston

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

Crystalline monomeric alkyltin(II) compounds were prepared using the β-N-functionalised ligand 2-pyridylbis(trimethylsilyl)methyl, C5H4N[C(SiMe3)2]-2 (R): (a) SnR2 1 from (LiR)2 and SnCl2 or Sn(OC6H3But2-2,6)2 (b) SnR(Cl) 2 from SnCl2 and SnR2 or 1/2;(LiR)2; and (c) SnR[N(SiMe3)2] 3 from Sn[N(SiMe3)2]2 and 1/2;(LiR)2. Single-crystal X-ray diffraction data showed that in each of 1-3 R- behaves as a chelating, C,N-centred ligand, and that the lone pair on tin is stereochemically active. The mean Sn-C [and Sn-NC5H4] bond lengths (Å) are 2.35(2) [2.42(2)] in 1, 2.32(2) [2.27(3)] in 2, and 2.356(8) [2.299(5)] in 3. Variable-temperature multinuclear (1H, 13C, 29Si and 119Sn) NMR spectral data were obtained for 1-3 in [2H8]toluene. These showed that dynamic processes were operative, believed to be Sn-N(C5H4) dissociations, with ΔG‡Tc = 43.5 ± 0.8 for 2 or 42.7 ± 0.8 kJ mol-1 for 3 (the coalescence temperature Tc being 220 ± 2 for 2 and 214 ± 2 K for 3); for 3 a further fluxion with ΔG‡Tc = 76.1 ± 0.8 kJ mol-1 (Tc = 368 ± 2 K) is attributed to the barrier to rotation about the tin-amide nitrogen bond. Attempts were made to reduce 2 [evidence for (SnR)n], and to prepare analogues of GeII and PbII of 1 and 2. A further β-functionalised complex, SnCl(OCBut2CH2PMe2) 4, was obtained from SnCl2 and 1/2;[Li(OCBut2CH2PMe2)]2; there was no evidence for 31P-119Sn coupling, and a plausible structure is [Sn(μ-Cl)(OCBut2CH2PMe2)] 2. A similar metathetical reaction between SnCl2 and Sn(OC6H3But2-2,6)2 in tetrahydrofuran (thf) gave 1/m[SnCl(OC6H3But2-2,6)(thf) n]m, whereas SnCl2 + SnR′2 [R′ = CH(SiMe3)2] yielded SnR′2Cl2 + Sn.

Original languageEnglish
Pages (from-to)2653-2663
Number of pages11
JournalJournal of the Chemical Society, Dalton Transactions
Issue number17
DOIs
Publication statusPublished - 7 Sep 1993
Externally publishedYes

Fingerprint Dive into the research topics of 'Subvalent Group 14 metal compounds: Part 16. Synthesis, crystal structure and characterisation of some β-functionalised-alkyltin(II) complexes, SnR(X){R = C5H4N[C(SiMe3)2]-2; X = R, Cl or N(SiMe3)2}'. Together they form a unique fingerprint.

Cite this