EFFECTS OF MOLECULAR-STRUCTURE UPON COMPLEX-SUPPORT INTERACTIONS

Two cationic, copper metal complexes with different ligands were synth esized: ethylenediamine (en) [Cu(C2N8N2)(ClO4)2] and diethanolamine (D eta) {[CuC8H21N2O4]ClO4}. These complexes were mounted on Cab-O-Sil us ing nonaqueous impregnation techniques, and the loadings were determin ed at which multilayers formed. These samples were analyzed for copper , carbon, nitrogen and hydrogen content to determine if ligand dissoci ation occurred during the impregnation. Samples were decomposed in a t hermal gravimetric apparatus to determine the kinetics of the thermoly sis reaction in air, and the evolved gases were analyzed by gas chroma tograph-mass spectrometry to determine the products of the thermolysis reaction. The results of these and earlier studies are summarized in a model that describes the effects of molecular structure upon complex -support interactions. Complexes with the ability to form hydrogen bon d interactions between the ligand and the support form strong interact ions with the surface of silica, whereas complexes without such hydrog en bond interactions are only weakly attracted to the silica surface. Strong interactions with the surface may also arise as a result of lig and dissociation and direct interaction of the metal ion with the surf ace oxygens. The charge on the complex and its shape play less importa nt roles in determining the affinity of the metal complex with the sil ica.