Study of the reaction of MoOS2(S2CNR2)2 with PPh3 in 1,2-dichloroethane: Part II. Detection of reaction intermediate pentavalent molybdenum using ESR method at low temperature

✍ Scribed by Song Xiaoqing; Yang Huixing; Han Degang

• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: English
• Weight: 243 KB
• Volume: 21
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550210903

✦ Synopsis

Intermediate product of the reaction of M O O S ~( S ~C N R ~) ~

and PPh3 in dichloroethane has been detected by ESR spectroscopy. Two ESR signals have been observed a t low temperature in the reaction system which was stopped by quenching it in liquid nitrogen. The g values are 2.020 ? 0.001 and 1.972 i 0.001 respectively. The signal a t g = 2.020 is attributed to a reaction intermediate with pentavalent molybdenum. A reaction mechanism has been proposed which is consistent with the observation of pentavalent molybdenum as the intermediate in the process of reaction.

' S(2)

An EHMO calculation of the net electron charges on the atoms in MoOS,(S,CNPr,), shows that there is the least-negative charge on S(2) atom [6]. This reaction is also the rate determining step of the overall reaction according to the kinetic studies. It is followed by the rapid formation of -S-S-PPh, bond and the decomposition to the final products.