t-Butylimido compounds of rhenium. X-ray crystal structures of [(Bu tN) 2Re(μ-NBu t)] 2, (Bu tN) 2ReCl 3, (Bu tN) 2ReCl 2C 6H 5, (Bu tN) 3Re(OSiMe 3) and (Bu tN) 3ReCl

• Published in: Polyhedron Vol. 8; no. 22; pp. 2657 - 2670
• Main Authors: Danopoulos, Andreas A., Longley, Cindy J., Wilkinson, Geoffrey, Hussain, Bilquis, Hursthouse, Michael B.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 1989
• Subjects: tmed = tetramethylethylenediamine o-tol = 2-MeC 6H 4; mes = 2,4,6-Me 3C 6H 2; xylyl = 2,6-Me 2C 6H 3
• ISSN: 0277-5387
• DOI: 10.1016/S0277-5387(00)80436-2

Previous studies on t-butylimido aryls of rhenium have been extended and the compounds (Bu t N) 2Rev VII( o-tol) 3, (Bu t N) 2Re VIICl 2Ph and (BU t N) 2Re VI(mes) 2 synthesized. Electrochemical studies of the latter show reversible one-electron oxidation and reduction, and chemical oxidation leads to the cation [(Bu t N) 2Rev VII(mes) 2] + isolated as PF 6 − and CF 3SO 3 − salts. Although the neutral complex does not undergo insertion with isocyanides, the cation does so to give η 2-iminoacyls, {(Bu t N) 2Re(mes)[η 2-RNC(mes)]} +, R = 2,6-xylyl, t-Bu. Reduction of (Bu t N) 3Re(OSiMe 3) in hexane by sodium gives the bridged homoleptic compound (Bu t N) 2Re(μ-NBu t ) 2Re(NBu t ) 2. The homoleptic anion [Re(NBu t ) 4] − as the Li(tmed) + complex has been synthesized via the new intermediates (Bu t N) 3ReCl and (Bu t N) 3Re(NHBu t ). X-ray crystal structures of the compounds listed in the title have been determined. The homoleptic rhenium(VI) t-butylimide is dimeric with four-coordinate rhenium and almost symmetrical imido bridges; the terminal imido groups have near linear geometry. The diamagnetism is consistent with a ReRe bond, although the ReRe distance of ca 2.7 Å indicates this to be weak. The rhenium(VII) siloxide is also four-coordinate distorted tetrahedral; and the geometries of the Re-imido and Re-siloxide units indicate involvement of all ligands in π-interactions. The (Bu t N) 3ReCl is also tetrahedral. The two bis-imido chloro compounds are five-coordinate with a geometry that can be conveniently described as trigonal bipyramidal where the imido groups occupy equatorial sites with unusually small inter-ligand angles of ca 110°.