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论文类型： 期刊论文

发表时间： 2010-11-28

发表刊物： DALTON TRANSACTIONS

收录刊物： SCIE、EI、PubMed、Scopus

卷号： 39

期号： 44

页面范围： 10697-10701

ISSN号： 1477-9226

摘要： Octahedral, trigonal prismatic, and capped square pyramidal structures have been optimized for the Ru6C(CO)(n) clusters (15 <= n <= 20) using density functional theory. The experimentally known very stable Ru6C(CO)(17) is predicted to have an octahedral structure in accord with experiment as well as the Wade-Mingos rules. The stability of Ru6C(CO)(17) is indicated by its high carbonyl dissociation energy of similar to 37 kcal mol(-1) and the high energy of similar to 33 kcal mol(-1) required for disproportionation into Ru6C(CO)(18) + Ru6C(CO)(16). Theoretical calculations predict a doubly carbonyl bridged octahedral Ru6C(CO)(17) structure to be similar to 0.7 kcal mol(-1) more stable than the experimentally observed singly bridged structure. A trigonal prismatic Ru6C(CO)(19) cluster isoelectronic with the known Co6C(CO)(15)(2-) dianion does not appear to be viable as indicated by a low carbonyl dissociation energy of 8.8 kcal mol(-1) and a required energy of only 4.9 kcal mol(-1) for disproportionation into Ru6C(CO)(20) + Ru6C(CO)(18). The predicted instability of Ru6C(CO)(n) (n >= 18) derivatives suggests a maximum of 17 external carbonyl groups around a stable polyhedral Ru6C structure.