Small angle X-ray scattering and IR spectroscopy study of metal carbonyl complexes immobilized on a silica gel surface chemically modified with piperazine

Abstract

The carbonyl complexes [WCl(CO) 3(bipy)(HgCl)] ( 1), Fe(CO) 4(HgCl) 2] ( 2 and [W(CO) 6] ( 3) were immobilized on a silica gel surface organofunctionalized with piperazine groups. The products obtained were studied by IR spectroscopy and small angle X-ray scattering (SAXS) techniques. The IR data show that the immobilization of heterobimetallic compounds 1 and 2, on the functionalized surface, occured through the mercury atom, while for 3 the displacement of one CO group by the nitrogen of a piperazine molecule was observed. The data obtained from SAXS indicate that particles have a uniform size and reveal suitable modifications on the functionalized surface after immobilization of metal carbonyl complexes. The average intermolecular distance l ij for piperazine ligands on support is 8.7 Å, for the metal carbonyl complex 1 it is 18.8 Å, for complex 2 it is 16.2 Å and for complex 3 it is 15.3 Å.