Structural diversity in divalent group 14 triflate complexes involving endocyclic thia-macrocyclic coordination

Abstract

A highly unusual series of M(II) (M = Ge, Sn, Pb) complexes with endocyclic thioether macrocyclic coordination and with coordination numbers ranging from three to nine have been prepared by the reaction of [9]aneS₃ (1,4,7-trithiacyclononane), [12]aneS₄ (1,4,7,10-tetrathiacyclododecane), or [24]aneS₈ (1,4,7,10,13,16,19,22-octathiacyclotetracosane) with M(OTf)₂ (M = Sn and Pb; OTf = CF₃SO₃^-) or with GeCl₂·dioxane and 2 mol equiv of TMSOTf (Me₃SiO₃SCF₃) in a mixture of anhydrous CH₂Cl₂ and MeCN. The isolated bulk products are characterized by ¹H, ¹³C{¹H}, ¹⁹F{¹H}, and ¹¹⁹Sn{¹H} NMR and IR spectroscopy, high-resolution ESI⁺ MS, and microanalytical data. Crystal structures are also reported for [M(L)][OTf]₂ (M = Ge, Sn, Pb; L = [9]aneS₃, [12]aneS₄) and for [M([24]aneS₈)][OTf]₂ (M = Sn, Pb). In all cases, the ligand is bound in an endocyclic fashion, but the coordination environment and number are highly dependent on the group 14 ion, the macrocyclic ring size, and the number of S-donor atoms it presents. Solution NMR spectroscopic data suggest that the metal-macrocycle coordination is retained in solution but that the triflate anions are extensively dissociated on the NMR timescale. Density functional theory calculations on the [M([9]aneS₃)]²⁺ and [M([12]aneS₄)]²⁺ (M = Ge, Sn, Pb) dications reveal that the HOMO is centered on the group 14 atom as a directional “lone pair”; it also retains a significant amount of positive charge.

More information

Identifiers

Catalogue record

Export record

ASCII CitationAtomBibTeXData Cite XMLDublin CoreDublin CoreEP3 XMLEndNoteHTML CitationHTML CitationHTML ListJSONMETSMODSMPEG-21 DIDLOpenURL ContextObjectOpenURL ContextObject in SpanRDF+N-TriplesRDF+N3RDF+XMLRIOXX2 XMLReferReference ManagerSimple Metadata

Altmetrics