Carboxylate versus imidobenzoate bonding for anthranilic acid derivatives.Crystal structures of [W(eta-C5Me5)Cl-3(eta(2)-O2CC6H4NH2-2)] and [ReCl(OEt)(PPh3)(2) (NC6H4CO2)]

The paramagnetic complex [W(eta -C5Me5)Cl-3 (eta (2)-O2CC6H4NH-2)] (1) has been obtained by reaction of [W(eta -C5Me5)Cl-4] with anthranilic acid [1,2 -(NH2)(CO2H)C6H4]; the X-ray crystal structure shows a pseudo-octahedral ge ometry with a mer arrangement of chlorines and a symmetrically chelating ca rboxylate group containing a pendant non-coordinated NH2 group. Contrasting ly, [ReCl(OEt) (PPh3)(2)(NC6H4CO2)] (2), the product of the reaction betwee n [ReOCl3(PPh3)(2)] and anthranilic acid contains pseudooctahedral rhenium with a chelating imidobenzoate ligand and trans-phosphines which are mutual ly cir to the bent imido function [Re-N(1)-C(1) = 143.5(3)degrees]. The car boxylate group of the chelating ligand is trans to a chloride with the rema ining site (trans to the imido function) occupied by an ethoxide ligand. (C ) 2001 Elsevier Science B.V. All rights reserved.