Kinetic and DFT Studies on the Mechanism of C鈥揝 Bond Formation by Alkyne Addition to the [Mo3S4(H2O)9]4+ Cluster

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• 作者：Jose 脕ngel Pino-Chamorro ; Andr茅s G. Algarra ; M. Jes煤s Fern谩ndez-Trujillo ; Rita Hern谩ndez-Molina ; Manuel G. Basallote
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：December 16, 2013
• 年：2013
• 卷：52
• 期：24
• 页码：14334-14342
• 全文大小：540K
• 年卷期：v.52,no.24(December 16, 2013)
• ISSN：1520-510X

文摘

Reaction of [Mo₃(渭₃-S)(渭-S)₃] clusters with alkynes usually leads to formation of two C鈥揝 bonds between the alkyne and two of the bridging sulfides. The resulting compounds contain a bridging alkenedithiolate ligand, and the metal centers appear to play a passive role despite reactions at those sites being well illustrated for this kind of cluster. A detailed study including kinetic measurements and DFT calculations has been carried out to understand the mechanism of reaction of the [Mo₃(渭₃-S)(渭-S)₃(H₂O)₉]⁴⁺ (1) cluster with two different alkynes, 2-butyne-1,4-diol and acetylenedicarboxylic acid. Stopped-flow experiments indicate that the reaction involves the appearance in a single kinetic step of a band at 855 or 875 nm, depending on the alkyne used, a position typical of clusters with two C鈥揝 bonds. The effects of the concentrations of the reagents, the acidity, and the reaction medium on the rate of reaction have been analyzed. DFT and TD-DFT calculations provide information on the nature of the product formed, its electronic spectrum and the energy profile for the reaction. The structure of the transition state indicates that the alkyne approaches the cluster in a lateral way and both C鈥揝 bonds are formed simultaneously.