| Abstract
| - Diimido complexes of the type Mo(NAr)2Cl2(dme) (dme = 1,2-dimethoxyethane) react with N-salicylidene-2-aminophenol (sapH2) in methanol in the presence of 2 equiv of triethylamine to form complexes with the generalformula Mo(NAr)(1,2-OC6H4NH)(sap). The structures of three of these compounds (NAr = 2,6-dimethylphenylimido(1), 2,4,6-trimethylphenylimido (2), 2-tert-butylphenylimido(3)) have been determined by X-ray crystallography. Thecoordination sphere around the Mo is a distorted octahedron. The oxygen from the 2-aminophenol is trans to theimido nitrogen, whereas the amido nitrogen and the tridentate sap occupy the four equatorial positions. The Mo−N−C imido linkages have angles of 167.5(2)° (1), 163.2(2)° (2), and 162.4(1)° (3). A precursor complex to theimido−amido complex, Mo(NAr)(sap)(OCH3)2 (4, NAr = 2,4,6-trimethylphenylimido), has been isolated andcharacterized. Compound 4 reacts with 2-aminophenol to form 2, with 2-aminothiophenol to form Mo(NAr)(1,2-SC6H4NH)(sap) (5), with catechol to form Mo(NAr)(1,2-OC6H4O)(sap) (6), with naphthalene-2,3-diol to formMo(NAr)(naphthalene-2,3-diolate)(sap) (7), with 1,2-benzenedithiol to form Mo(NAr)(1,2-SC6H4S)(sap) (8), and with1,2-phenylenediamine to form Mo(NAr)(1,2-HNC6H4NH)(sap) (9). The structures of compounds 5−9 have beendetermined by X-ray crystallography. With the exception of compound 8, the structures are similar to those of 1,2, and 3, with the bidentate ligand occupying one axial and one equatorial position. In 8, 1,2-benzendithiolateoccupies two equatorial positions, and the nitrogen from sap is located trans to the imido nitrogen. All complexeswere characterized by 1H NMR spectroscopy, cyclic voltammetry, and UV−vis spectroscopy. When a solution of 4is exposed to moisture-containing air, MoO2(sap)(CH3OH) (10) is formed. The structure of 10 was also determined.
- The reaction of Mo(NAr)2Cl2(dme) with N-salicylidene-2-aminophenol (sap) yields the complex Mo(NAr)(1,2-OC6H4NH)(sap). An intermediate in this reaction, Mo(NAr)(sap)(OCH3)2, has been isolated and used to synthesize a number of complexes with bidentate aromatic ligands. The complexes have been characterized by X-ray crystallography, 1H NMR spectroscopy, cyclic voltammetry and spectroelectrochemistry. All compounds have a reversible one-electron reduction from Mo(VI) to Mo(V).
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