A weak η1 π-bonding mode for Ru-arene complexes.: Nitrile, isonitrile and phosphine derivatives of Ru-phosphino-arene chelating complexes

The synthesis of new derivatives based on a Ru(Ph2P-arene)(POHPh2) fragment, possessing nitrile, isonitrile and phosphine ligands, are reported. The new nitrile compounds, e.g. [Ru(H2O)(RCN)(2)(Ph2P-eta(1)arene)(POHPh2)](OTf)(2), R = Me, p-tolyl, reveal a new and unexpected weak eta(1) pi-bonding mode from a single CH-biaryl arene carbon to the ruthenium atom. as demonstrated by C-13-NMR. The solid-state structures for two examples are reported. In one complex a new Ru-P-O-C=N-H five-membered ring is formed due to the P-OH oxygen attack on the complexed p-tolyl nitrile. (C) 2002 Elsevier Science B.V. All rights reserved.