STUDY OF ADSORBATE INTERACTIONS OF CU(II) ION-EXCHANGED INTO SILICEOUS MCM-41 SILICA TUBE MATERIAL BY ELECTRON-SPIN-RESONANCE AND ELECTRON-SPIN ECHO MODULATION SPECTROSCOPY

The interaction of Cu(II) with deuterated adsorbates in Cu(II)-ion-exc hanged siliceous MCM-41 silica tube material was studied by electron s pin resonance (ESR) and electron spin echo modulation (ESEM) technique s. It was found that polar adsorbates such as CH3OH and C5H5N remove C u(II) from its ion exchange site to form [CU(CH3OH)(6)](2+) and [CU(C5 H5N)(4)](2+) complexes. Cu(II) also forms complexes with two ethylenes and one benzene based on ESEM data. The ESR experiments suggest that dispersion forces of the adsorbed nonpolar molecules affect the locati on of the Cu(II) ions, but the cupric ions remain coordinated to frame work oxygens in complexes formed with ethylene and benzene. The change s of the Cu(II) location induced by interaction with various adsorbate s support weak bonding of the Cu(II) ions to the framework in siliceou s MCM-41.