摘要
采用单层分散法(monolayer dispersion)将 Ru3(CO)(12)引入NaY分子筛的孔道中,借助FTIR,EXAFS和UV-VIS等实验手段对其进行测定,发现Ru3(CO)(12)完整地分布于分子筛的超笼内,抽空会导致在保持金属骨架情况下的部分脱羰,同时伴随着桥式羰基谱带的出现,这意味着表面次羰基加合物的形成.原子簇上的羰基配体可以同(13)CO同位素进行交换反应.Ru3(CO)(12)/NaY在氧气中完全脱羰后,如果与CO发生反应,将生成具有Ru3 结构的次羰基物.微量H2O的引入可以使其恢复到初始态的Ru3(CO)(12).
Ru3(CO)12 was introduced into the supercages of NaY zeolite by monolayer dispersion technique, which gives IR absorption bands at 2068 vs, 2028 s and 2124 w cm^(-1), very similar to those of Ru3(CO)12 dissolved in organic solvent and completely different from the spectrum of the mechanical mixture of Ru3(CO)12 and NaY zeolite prior to mono-layer dispersion process, suggesting Ru3(CO)12 homogeneously dispersed in zeolite cages. The characterization by UV-VIS and EXAFS also supported the existence of ruthenium cluster as a whole in NaY zeolite. Some of carbonyls of Ru3(CO)12/NaY were eliminated after evacuation at room temperature to form a subcarbonyl cluster containing bridging carbonyl, which can not restore the structure of original one, indicating that there is an interaction between the subcarbonyls thus formed and zeolite surface. Ru3(CO)12/NaY showed very high activity for isotopic exchange with ~13CO. Ru3 skeleton could be reconstructed by the reaction of CO with Ru3Ox.
