Electron spin resonance and electron spin echo modulation studies on the formation and adsorbate interactions of Ni(I) in synthetic clinoptilolite

Electron spin resonance (ESR) and electron spin echo modulation (ESEM) spec troscopies were used to study the formation of Ni(I) by various reduction m ethods and various adsorbate interactions of Ni(I) in synthetic clinoptilol ite, in which Ni(II) was ion-exchanged into extraframework sites of clinopt ilolite. Thermal reduction by dehydration at 573 K shows a single species a ssigned to Ni(I) ions. Two isolated Ni(I) ions are observed after hydrogen reduction at 623 K. Adsorption of methanol on hydrogen-reduced NiNaK-Clino forms a Ni(I)-(CD3OH)(n) complex resulting from the interaction of methanol with one of the isolated Ni(I) ions. Adsorption of ammonia on hydrogen-red uced NiNaK-Clino produces a prominent Ni(I)-(ND3)(n) complex by interaction with both Ni(I) ions. The C-13 hyperfine structure and ESEM analysis param eters after (CO)-C-13 adsorption indicate that Ni(I) interacts with one CO molecule and forms a NI(I)-(CO)(1) complex. Two Ni(I)-(C2D4)(n) complexes a re generated after adsorption of ethylene on dehydrated Ni(II)NaK-Clino and subsequent heating below 623 K. At higher temperature, these species disap pear with the concomitant formation of two Ni(I)-(C4D8)(n) complexes, indic ating ethylene dimerization. D-2 ESEM confirms the coordination of Ni(I) wi th butene. Adsorption of NO on dehydrated Ni(II)NaK-Clino produces two Ni(I )-NO+ complexes formed by transfer of the odd electron from NO to Ni(II) io ns. Along with two Ni(I)-NO+ species, another species assigned to the NO ra dical is also observed in NiNaK-Clino after NO adsorption on Ni(II)NaK-Clin o and NaK-Clino.