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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 31, Number 4
BKCSDE 31(4)
April 20, 2010 

 
Title
A Density Functional Theory Investigation on Intramolecular Hydrogen Transfer
of the [Os3(CO)11P(OMe)3(Ru(管5-C5H5))2] Cluster
Author
Radchada Buntem*, Kraiwan Punyain, Yuthana Tantirungrotechai*, Paul R Raithby, Jack Lewis
Keywords
DFT, Osmium-carbonyl cluster, Intramolecular hydrogen transfer
Abstract
The reduction of [Os3(CO)11P(OMe)3] and subsequent ionic coupling of the reduced species with [Ru(管5-C5H5) (CH3CN)3]+ resulted in the formation of [Os3(CO)11P(OMe)3(Ru(管5-C5H5))2] which can be converted to spiked tetrahedral cluster, [HOs3(CO)11P(OMe)3Ru2(管5-C5H5)(C5H4)] via the intramolecular hydrogen transfer. Due to the unavailability of a suitable single crystal, the PW91/SDD and LDA/SDD density functional methods were used to predict possible structures and the available spectroscopic information (IR, NMR) of [Os3(CO)11P(OMe)3(Ru(管5- C5H5))2]. The most probable geometry found by constrained search is the isomer (a2) in which the phosphite, P(OMe)3, occupies an axial position on one of the two osmium atoms that is edge bridged by the Ru(CO)2(管5-C5H5) unit. By using the most probably geometry, the predicted infrared frequencies and 1H, 13C and 31P NMR chemical shifts of the compound are in the same range as the experimental values. For this type of complex, the LDA/SDD method is appropriate for IR predictions whereas the OPBE/IGLO-II method is appropriate for NMR predictions. The activation energy and reaction energy of the intramolecular hydrogen transfer coupled with the structural change of the transition metal framework were estimated at the PW91/SDD level to be 110.32 and ?0.14 kcal/mol respectively.
Page
934 - 940
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