Rhenium nitrido-, arylimido-, nitrite, and carbonyl complexes with sterically hindered thiolate ligands

Abstract

By the reaction of [ReNCl₂(PR′₃)_n](PR′₃= PPh₃, n= 2; or PMe₂Ph, n= 3) with the bulky thiol 2,4,6-tri-isopropylbenzenethiol (Htipt) under varying conditions, the nitrido-complexes [ReN(tipt)₂(PR′₃)₂], Na₂[ReN(tipt)₄]·2thf (thf = tetrahydrofuran), and [PPh₄][ReN(tipt)₄] have been isolated. The last is a paramagnetic rhenium(VI) complex derived from the aerial oxidation of the rhenium(V) anion [ReN(tipt)₄]^2–. The arylimidorhenium(V) complexes [PPh₄][Re(NR″)(tipt)₄](R″= Ph, C₆H₄OMe-4, or C₆H₄Me-4) can be isolated by the reaction of [Re(NR″)Cl₃(PPh₃)₂] with Htipt and triethylamine, whereas N₂ loss occurs with PhS^–. The complexes [Re(tipt)₃(NCR‴)₂](R‴= Me or Bu^t) have been prepared by reaction of K₂[ReCL₆] with Htipt and triethylamine in R‴CN as solvent. These bis(nitrile) complexes have a trigonal-bipyramidal structure with equatorial thiolate ligands. They react with CO to give, sequentially, two isomers of [Re(tipt)₃(CO)(NCR‴)] and then [Re(tipt)₃(CO)₂] which have analogous structures. Analogues of some of the complexes, containing 2,4,6-trimethylbenzenethiolate or 2,6-di-isopropylbenzenethiolate ligands, are also described.