Mononuclear and dinuclear complexes with a [Ru(tBu2PCH2CH2PtBu2)(CO)] core

Abstract

Thermolysis of solid [Ru(d^tbpe)(CO)₂Cl₂] (2, d^tbpe = ^tBu₂PCH₂CH₂P^tBu₂) under vacuum affords the five-coordinate complex [Ru(d^tbpe)(CO)Cl₂] (4), which was shown by X-ray crystallography to contain a weak remote agostic interaction. In solution, 4 can be readily trapped by CO, CH₃CN or water to give [Ru(d^tbpe)(CO)(L)Cl₂] (L = CO, 2; L = CH₃CN, 6; L = H₂O, 7). Reaction of 4 with AgOTf/H₂O yields the tris-aqua complex [Ru(d^tbpe)(CO)(H₂O)₃](OTf)₂ (8), which has been structurally characterised and probed in solution by pulsed-gradient spin echo (PGSE) NMR spectroscopy. The water ligands in 8 are labile and easily substituted to give [Ru(d^tbpe)(CO)(NCCH₃)₃](OTf)₂ (10) and [Ru(d^tbpe)(CO)(DMSO)₃](OTf)₂ (11). In the presence of CO, the tris-aqua complex undergoes water–gas shift chemistry with formation of the cationic hydride species [Ru(d^tbpe)(CO)₃H](OTf) (12) and CO₂. X-Ray crystal structures of complexes 2, 4, 6, 8 and 11–12 are reported along with those for [{Ru(d^tbpe)(CO)}₂(µ-Cl)₂(µ-OTf)](OTf) (3), [{Ru(d^tbpe)(CO)}₂(µ-Cl)₃][Ru(d^tbpe)(CO)Cl₃] (5) and [Ru(d^tbpe)(CO)(H₂O)₂(OTf)](OTf) (9).