Format

Send to:

Choose Destination
See comment in PubMed Commons below
Inorg Chem. 2006 Mar 6;45(5):2307-16.

Mononuclear [NiII(L)(P-(o-C6H4S)2(o-C6H4SH))]0/1- (L = thiolate, selenolate, PPh3, and Cl) complexes with intramolecular [Ni...S...H...S]/[Ni...H...S] interactions modulated by the coordinated ligand L: relevance to the [NiFe] hydrogenases.

Author information

  • 1Department of Chemistry, National Tsing Hua University, Hsinchu 30043, Taiwan.

Abstract

The shift of the IR nu(S)(-)(H) frequency to lower wavenumbers for the series of complexes [Ni(II)(L)(P-(o-C6H4S)2(o-C6H4SH))]0/1- (L = PPh3 (1), Cl (6), Se-p-C6H4-Cl (5), S-C4H3S (7), SePh (4)) indicates that a trend of increasing electronic donation of the L ligands coordinated to the Ni(II) center promotes intramolecular [Ni-S...H-S] interactions. Compared to the Ni...S(H) distance, in the range of 3.609-3.802 A in complexes 1 and 4-7, the Ni...S(CH3) distances of 2.540 and 2.914 A observed in the [Ni(II)(PPh3)(P(o-C6H4S)2(o-C6H4-SCH3))] complexes (8a and 8b, two conformational isomers with the chemical shift of the thioether methyl group at delta 1.820 (-60 degrees C) and 2.109 ppm (60 degrees C) (C4D8O)) and the Ni...S(CH3) distances of 3.258 and 3.229 A found in the [Ni(II)(L)(P(o-C6H4S)2(o-C6H4-SCH3))]1- complexes (L = SPh (9), SePh (10)) also support the idea that the pendant thiol protons of the Ni(II)-thiol complexes 1/4-7 were attracted by both the sulfur of thiolate and the nickel. The increased basicity (electronic density) of the nickel center regulated by the monodentate ligand attracted the proton of the pendant thiol effectively and caused the weaker S...H bond. In addition, the pendant thiol interaction modes in the solid state (complexes 1a and 1b, Scheme 1) may be controlled by the solvent of crystallization. Compared to complex 1a, the stronger intramolecular [Ni-S...H-S] interaction (or a combination of [Ni-S...H-S]/[Ni...H-S] interactions) found in complexes 4-7 led to the weaker S-H bond strength and accelerated the oxidation (by O2) of complexes 4-7 to produce the [Ni(Y)(L)(P(o-C6H4S)3)]1- (L = Se-p-C6H4-Cl (11), SePh (12), S-C4H3S (13)) complexes.

PMID:
16499397
[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for American Chemical Society
    Loading ...
    Write to the Help Desk