TY - JOUR
T1 - Steric titration of arylthiolate coordination modes at pseudotetrahedral nickel(II) centers
AU - Chattopadhyay, Swarup
AU - Deb, Tapash
AU - Petersen, Jeffrey L.
AU - Young, Victor G.
AU - Jensen, Michael P.
PY - 2010/1/18
Y1 - 2010/1/18
N2 - 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.
AB - 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.
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U2 - 10.1021/ic901347p
DO - 10.1021/ic901347p
M3 - Article
C2 - 20000833
AN - SCOPUS:74549165393
SN - 0020-1669
VL - 49
SP - 457
EP - 467
JO - Inorganic chemistry
JF - Inorganic chemistry
IS - 2
ER -