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 But) 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.