ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 48, Number 5
JKCSEZ 48(5)
October 20, 2004 

The homobimetallic anion, M+(h5-MeCp)Mn(CO)2Mn(CO)5-(M+=Na+, PPN+) was disrupted by CH2CHCH2Cl in THF at various temperatures (20 oC~50 oC) under the pseudo 1st order reaction conditions where excess of allyl chloride was employed under a nitrogen atmosphere. This homobimetallic anion seems to be involved in a concerted reaction mechanism in which a four-centered transition state is proposed. After undergoing the transition state, this reaction eventually leads to (MeCp)Mn(CO)3 on addition of CO and (h1-allyl)Mn(CO)5, respectively. However, in case of Na+ analog, Na+ may play a novel counter ion effect on the disruption reaction either by transferring one terminal CO from the Mn(CO)5 moiety on to the (h5-MeCp)Mn(CO)2 of the corresponding homobimetallic complex, eventually resulting in (h5-MeCp)Mn(CO)3 or through the interaction between Na+ and the leaving group (Cl) of allyl chloride. This reaction is of overall second order with respect to homobimetallic complex with the activation parameters (DH? 17.15?.17 kcal/mol, DS? -9.63?.10 e.u. for Na+ analog; DH?22.13?.21 kcal/mol, DS?9.74?.19 e.u. for PPN+ analog reaction).