Comparison of Thermodynamic and Kinetic Aspects of Oxidative Addition of PhE−EPh (E = S, Se, Te) to Mo(CO)3(PR3)2, W(CO)3(PR3)2, and Mo(N[tBu]Ar)3 Complexes. The Role of Oxidation State and Ancillary Ligands in Metal Complex Induced Chalcogenyl Radical Generation

James E. McDonough, John J. Weir, Kengkaj Sukcharoenphon, Carl D. Hoff,* Olga P. Kryatova, Elena V. Rybak-Akimova,* Brian L. Scott, Gregory J. Kubas,* Arjun Mendiratta, and Christopher C. Cummins*
Contribution from the University of Miami, Coral Gables, Florida 33124, Tufts University, Medford, Massachusetts 02155, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, and Los Alamos National Laboratory, Structural Inorganic Chemistry Group, Chemistry Division, MS J514, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
J. Am. Chem. Soc., 2006, 128 (31), pp 10295–10303
DOI: 10.1021/ja063250+
Publication Date (Web): July 13, 2006
Copyright © 2006 American Chemical Society
*

In papers with more than one author, the asterisk indicates the name of the author to whom inquiries about the paper should be addressed.

, c.hoff@miami.edu

Abstract

Abstract Image

Enthalpies of oxidative addition of PhE−EPh (E = S, Se, Te) to the M(0) complexes M(PiPr3)2(CO)3 (M = Mo, W) to form stable complexes M(•EPh)(PiPr3)2(CO)3 are reported and compared to analogous data for addition to the Mo(III) complexes Mo(N[tBu]Ar)3 (Ar = 3,5-C6H3Me2) to form diamagnetic Mo(IV) phenyl chalcogenide complexes Mo(N[tBu]Ar)3(EPh). Reactions are increasingly exothermic based on metal complex, Mo(PiPr3)2(CO)3 < W(PiPr3)2(CO)3 < Mo(N[tBu]Ar)3, and in terms of chalcogenide, PhTe−TePh < PhSe−SePh < PhS−SPh. These data are used to calculate LnM−EPh bond strengths, which are used to estimate the energetics of production of a free •EPh radical when a dichalcogenide interacts with a specific metal complex. To test these data, reactions of Mo(N[tBu]Ar)3 and Mo(PiPr3)2(CO)3 with PhSe−SePh were studied by stopped-flow kinetics. First- and second-order dependence on metal ion concentration was determined for these two complexes, respectively, in keeping with predictions based on thermochemical data. ESR data are reported for the full set of bound chalcogenyl radical complexes (PhE•)M(PiPr3)2(CO)3; g values increase on going from S to Se, to Te, and from Mo to W. Calculations of electron densities of the SOMO show increasing electron density on the chalcogen atom on going from S to Se to Te. The crystal structure of W(•TePh)(PiPr3)2(CO)3 is reported.

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  • Published In Issue August 09, 2006
  • Received May 9, 2006

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