An-Najah Staff

Thiomorpholine (tetrahydro-1,4-thiazine), in the presence of Os(VIII) as catalyst, is oxidized by alkaline hexacyanoferrate(III) to 2-hydroxythiomorpholine. There is a first-order dependence in [Fe(CN)₆^3-] and [Os(VIII)] and zero-order dependence in [thiomorpholine] and [OH^-]. The observed rate constant was dependent on [Fe(CN)₆^4-] the type of electrolyte and the permitivitty of the reaction medium (10-40% ethanol). The proposed mechanism includes the formation of a transient [OsO₄(OH)₂ ]^2--thiomorpholine complex prior to the rate-determining regeneration of Os^VIII by [Fe(CN)₆^3-]. The values of the enthalpy and entropy of activation are calculated from rate constant values measured at different temperatures (20-40 ° C).

Isomerization and hydrosilylation reactions of terminal olefins have been reported under thermal and photochemical conditions using Ru3 (C0) 12, 1, and HRu3 (CO)!!, 2,11 '0 In a very recent work, we reported E LI that 1 catalyses both Isomerization and hydrosilylation reactions of 1-octene (eq. 1). It has been found that the isomerization reaction occurs via lower nuclearity catalytic species that result from fragmentation of the mother cluster 1. Evidence in favour of concurrent cluster catalysis was also reported. On the other hand, the hydrosilylation reaction occurred via cluster catalysis at first and after some-time fragment catalysis occurred.

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