Supramolecular assemblies of tungsten complexes with unusual chelating groups

Abstract

Metal complexes of ligands with η 1- O coordinated carbonyl moieties are well-known throughout the inorganic literature. However, metal complexes containing authentic acid chloride ligands have not previously been isolated. The synthesis and characterization of compounds with the formula W(X)Cl 3(OPh-2-COCl) ( 2) [X  O ( 2a), NC 6H 3-2,6-(CH 3) 2 ( 2b), and Ph 2C 2 ( 2c)] are reported. The crystal structures of 2a and 2c were solved, showing the interaction of the acid chloride carbonyl moiety with the tungsten center. Complex 2c adopts a channelled structure having six-fold symmetric voids in the solid state. As was anticipated, the coordinated acid chloride of 2a reacts readily with nucleophiles to produce the ester WOCl 3(OPh-2-COPr n ) ( 3) and the amide WOCl 3(OPh-2-CONHBu t ) ( 4a). A related amide complex WOCl 3(OPh-2-CONH 2) ( 4b), synthesized by the reaction of WOCl 4 with salicylamide, displays an infinite-chain structure supported by hydrogen bonding between the amide group and the oxo ligand of an adjacent tungsten complex. The η 1- O coordinated nitro compounds W(X)Cl 3(OPh-2-NO 2) ( 5) [X  O ( 5a), NC 6H 3-2,6-(CH 3) 2 ( 5b), and Ph 2C 2 ( 5c)] have also been isolated and the crystal structure of 5c is reported.