Carboxylate versus imidobenzoate bonding for anthranilic acid derivatives. Crystal structures of [W(η-C5Me5)Cl3(η2-O2CC6H4NH2-2)] and [ReCl(OEt)(PPh3)2(NC6H4CO2)]

The paramagnetic complex [W(η-C5Me5)Cl3(η2-O2CC6H4NH2-2)] (1) has been obtained by reaction of [W(η-C5Me5)Cl4] with anthranilic acid [1,2-(NH2)(CO2H)C6H4]; the X-ray crystal structure shows a pseudo-octahedral geometry with a mer arrangement of chlorines and a symmetrically chelating carboxylate group containing a pendant non-coordinated NH2 group. Contrastingly, [ReCl(OEt)(PPh3)2(NC6H4CO2)] (2), the product of the reaction between [ReOCl3(PPh3)2] and anthranilic acid contains pseudo-octahedral rhenium with a chelating imidobenzoate ligand and trans-phosphines which are mutually cis to the bent imido function [Re–N(1)–C(1)=143.5(3)°]. The carboxylate group of the chelating ligand is trans to a chloride with the remaining site (trans to the imido function) occupied by an ethoxide ligand.