Substituent effects on Ni-S bond dissociation energies and kinetic stability of nickel arylthiolate complexes supported by a bis(phosphinite)-based pincer ligandElectronic supplementary information (ESI) available: X-ray crystallographic data in CIF and PDF formats, kinetic data, and plots of these data. CCDC 872168-872175 (complexes 1b, 1d, 1e, and 2a-e). For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c2dt30407d

• Main Authors: Zhang, Jie, Adhikary, Anubendu, King, Krista M, Krause, Jeanette A, Guan, Hairong
• Format: Journal Article
• Language: English
• Published: 15.06.2012
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c2dt30407d

Pincer complexes of the type [2,6-(R 2 PO) 2 C 6 H 3 ]NiSC 6 H 4 Z (R = Ph and i-Pr; Z = p -OCH 3 , p -CH 3 , H, p -Cl, and p -CF 3 ) have been synthesized from [2,6-(R 2 PO) 2 C 6 H 3 ]NiCl and sodium arylthiolate. X-ray structure determinations of these thiolate complexes have shown a somewhat constant Ni-S bond length (approx. 2.20 Å) but an almost unpredictable orientation of the thiolate ligand. Equilibrium constants for various thiolate exchange (between a nickel thiolate complex and a free thiol, or between two different nickel thiolate complexes) reactions have been measured. Evidently, the thiolate ligand with an electron-withdrawing substituent prefers to bond with "[2,6-(Ph 2 PO) 2 C 6 H 3 ]Ni" rather than "[2,6-(i-Pr 2 PO) 2 C 6 H 3 ]Ni", and bonds least favourably with hydrogen. The reactions of the thiolate complexes with halogenated compounds such as PhCH 2 Br, CH 3 I, CCl 4 , and Ph 3 CCl have been examined and several mechanistic pathways have been explored. Effects of ligand substituents on Ni-S bond lengths, bond dissociation energies, and nucleophilicity of a series of nickel thiolate complexes have been investigated.