Steric titration of arylthiolate coordination modes at pseudotetrahedral nickel(II) centers

Swarup Chattopadhyay, Tapash Deb, Jeffrey L. Petersen, Victor G. Young, Michael P. Jensen

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11 Scopus citations


Several derivatives of the pseudotetrahedral phenylthiolate complex Tp Me,MsNi-SPh (1), TpMe,Me- = hydrotris(3,5dimethyl-1- pyrazolyl)borate, were prepared incorporating substituted arylthlolates, including a series of orthosubstituted ligands TpMe,MeNi-SR (R = 2,6-Me2C6H3,2; 2,4,6-Me3C 6H2,3; 2,4,6- Pr3C6H2,4; and 2,6-Ph2C6H3,5) and a series of para-substituted complexes (R = C6H4-4-OMe, 6; C 6H4-4-Me, 7; and C6H4-4-CI, 8). The products were characterized by 1H NMR and UV-vis spectroscopy. Spectra of 6-8 were consistent with retention of a common structure across the para-substituted series with modest perturbation of the spectral features of 1 assisting their assignment. In contrast, spectra of 2-5 were indicative of a significant change in configuration across the orthodisubstituted series. The structure of complex 5 was determined by X-ray crystallography and a distinctive arylthiolate ligation mode was found, in which the N3S ligand field was significantly distorted toward a sawhorse, compared to a more common trigonal pyramidal shape (e.g., 1). Moreover, the arylthiolate substituent rotated from a vertical orientation co-directional with the pyrazole rings and disposed between two of them in 1, to a horizontal orientation perpendicular to and over a single pyrazole ring in 5. This reorientation is necessary to accommodate the large ortho substituants of the latter complex. The divergent Ni-S coordination modes result in distinct 1H NMR and electronic spectra that were rationalized by density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. These results demonstrate rich coordination chemistry for arylthlolates that can be elicited by steric manipulation at the periphery of pseudotetrahedral ligand fields.

Original languageEnglish (US)
Pages (from-to)457-467
Number of pages11
JournalInorganic Chemistry
Issue number2
StatePublished - Jan 18 2010


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