Dispersion energy donor ligand supports the isolation of Ge(II), Sn(II), and Lewis-base free Pb(II) arylthiolate dimers {M(SC6H2-2,4,6-Cy3)2}2 (M = Ge, Sn, Pb; Cy = cyclohexyl)

• Published in: Polyhedron Vol. 252; p. 116877
• Main Authors: McLoughlin, Connor P., Witt, Anthony J., Nelson, Jonah P.D., Tuononen, Heikki M., Power, Philip P.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-04-2024
• Subjects: Dispersion energy; Main group; Organometallic; Thiolates; Main group; Organometallic; Dispersion energy; Thiolates
• DOI: 10.1016/j.poly.2024.116877
• ISSN: 0277-5387

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•The dispersion energy donor ligand 2,4,6-tricyclohexylphenylthiol was used in the synthesis and isolation of three rare tetrel {M = Ge(II), Sn(II), Pb(II)} arylthiolates {M(SC6H2-2,4,6-Cy3)2}2.
We report the isolation of a series of cyclohexyl-substituted, homoleptic main group arylthiolates, {Ge(SC6H2-2,4,6-Cy3)2}2 (1), {Sn(SC6H2-2,4,6-Cy3)2}2 (2), and {Pb(SC6H2-2,4,6-Cy3)2}2 (3), as well as an improved one-pot synthesis of the thiol HSC6H2-2,4,6-Cy (4) with increased purity and yield. The solid-state structures of compounds 1–3 show that the group 14 atoms are bridged by two thiolato ligands whose hydrocarbon substituents are in either cis (1 and 2) or trans (3) conformations. In solution, the Ge(II) derivative 1 exists as a mixture of dimeric cis and trans isomers or as the monomer Ge(SC6H2-2,4,6-Cy3)2, as inferred from 1H NMR data. Contrary to a previous report of derivatives of the isopropyl-substituted thiol HSC6H2-2,4,6-Pri3, which led to the formation of a Ge(IV) hydride, no such hydride was observed during the synthesis of 1. Computational studies showed that the dimeric structure of 1 is stabilized by intramolecular dispersion interactions that are higher than those in similar systems employing the isopropyl-substituted ligand, in agreement with the preferred formation of HGe(SC6H2-2,4,6-Pri3)3 over the putative dimer {Ge(SC6H2-2,4,6-Pri3)2}2, although the exact mechanism leading to the hydride remains unclear. The corresponding Sn(II) derivative 2 is the first structurally characterized dimeric tin(II) thiolate. The Pb(II) species 3 is a rare example of a lead(II) arylthiolate that crystallizes in the absence of additional donor molecules.