51371-63-2Relevant academic research and scientific papers
Kinetics of the Scrambling Reaction between Dimanganese and Dirhenium Decacarbonyl
Marcomini, Antonio,Poe, Anthony
, p. 6952 - 6958 (1983)
The scrambling reaction between Mn2(CO)10 and Re2(CO)10 to form MnRe(CO)10 proceeds cleanly to a stable equilibrium in decalin at 170-190 deg C.Studies of the initial rates show that two paths are followed, the major one being evident over the whole range of temperatures and partial pressures of CO above the solutions.The kinetics suggest that it involves prior aggregation to form Mn2Re2(CO)20 which undergoes stepwise loss of CO to form the clusters Mn2Re2(CO)20-n (n = 4).All these clusters can be envisaged to be quasitetrahedral and to contain one Mn-Mn and one Re-Re bond together with n Mn-Re bonds and 4 - n Mn(μ-CO)Re bonds.When the requisite number of CO ligands have been removed the Mn-Mn and Re-Re bonds are lost, either by CO insertion or by redistribution of the M-M and M(μ-CO)M bonds within the cluster.Further Co insertion leads to Mn2Re2(CO)20 containing two Mn-Re bonds, and this readily fragments to form MnRe(CO)10.At low partial pressures of CO the rate-determining step is the formation of Mn2Re2(CO)20 or Mn2Re2(CO)19 and the activation parameters are ΔH = 22 +/- 2 kcal mol-1 and ΔS = -20 +/- 6 cal K-1 mol-1.The other path is most evident at 190 deg C under small partial pressures of CO, and it appears to involve prior loss of CO from decacarbonyls before aggregation.The kinetics suggest that scrambling occurs mainly via the tetranuclear intermediate Mn2Re2(CO)16.
Kinetics and Machanisms of Substitution Reactions on Decacarbonylmanganeserhenium
Sonnenberger, Dave,Atwood, Jim D.
, p. 3484 - 3489 (2007/10/02)
The kinetics of substitution reactions on decacarbonylmanganeserhenium, MnRe(CO)10, are reported for the entering ligands P(C6H5)3, P(C4H9)3, and P(OC6H5)3.Synthesis of all products and careful infrared analysis have allowed complete product assignment.For all three ligands the rhenium-substituted product, (CO)5MnRe(CO)4L, predominates, although formation of the bis-substituted product, L(CO)4MnRe(CO)4L, can be quite significant depending on the reaction conditions.A very small amount of the manganese isomer, L(CO)4MnRe(CO)5, was formed early in the reaction.In no cases were the homodimetallic species (Mn2(CO)10 or Re2(CO)10) or substituted derivatives of the diatomics observed.The manganese isomer fails to rearrange to the rhenium isomer under the conditions of the kinetics reaction.The rate constants and activation parameters are nearly identical for the three ligands.These data strongly suggest that CO dissiciation is the rate-determining step and are inconsistent with cleavage of the manganese-rhenium bond.Our proposed mechanism involves CO dissosiation from the manganese center and an intermediate/transition state with carbon monoxide bridging the manganese and rhenium.
