Synthesis and functional studies of transition metal complexes derived from amido and imido p v ligands

Abstract

Imido analogues of common phosphorus oxo anions have been the topic of immense research interest in main group chemistry and are employed as ligands in coordination chemistry Earlier reported procedures to access these imido P V anions involve the use of highly reactive main group metal reagents in reaction with a phosphonium salt like RNH 4P Cl or phosphoramides such as RNH 3P E E NSiMe3 O S or Se or with preformed iminophosphoranes However due to the highly reactive nature of these metal precursors as well as to the presence of residual metal alkyl aryl halide silylamide bonds in these complexes the imido ligand chemistry has largely been limited to main group metal ions in anhydrous aprotic and non polar solvents In this effort we have developed new synthetic routes in which salts of Cu I Ag I were shown to be efficient in deprotonating phosphonium cation such as NH2Py 4P or the phosphoric triamide NH2Py 3PO 2Py 2 pyridyl and leads to the formation of imido anions analogous to H2PO4 8722 and HPO42 8722 ions in CH3OH H2O medium Employing the salts of Pd II ions in deprotonation reactions an efficient and facile route to access the highly basic trianion RN 3PO 3 8210 analogous to PO43 8722 ion as its tri or hexa nuclear Pd II complexes was developed In addition to their structural novelty these imido Pd II clusters serve as excellent synthons for supramolecular assemblies and as efficient catalysts for organic transformations In related systems peripherally functionalized multi site amido P V ligands have been synthesized and employed in generating several novel functional materials For example coordination polymers of composition ZnL HCO2 8734 and CuL2 H2O 2 8734 were synthesized from an in situ generated ligand PO2 NH4Py 2 8722 L 175 These polymers exhibit a high preferential adsorption of water vapours over alcohols having industrial implication in the purification of bioethanol newline newline