Bis(3,5-dimethylpyrazol-1-yl)acyl and Bis(3,5-dimethylpyrazol-1-yl)methide Carbonyl Tungsten Derivatives

摘要

Reaction of (isopropyl)diphenylstannylbis(3,5-dimethylpyrazol-1-yl)methane [(i-Pr)Ph2SnCH(3,5-Me(2)Pz)(2)] and tricyclohexylstannylbis(3,5-dimethylpyrazol-1-yl)methane [Cy3SnCH(3,5-Me(2)Pz)(2)] with W(CO)(5)THF in refluxing THF yields heterobimetallic complexes (i-Pr)Ph2SnCH(3,5-Me(2)Pz)(2)W(CO)(4) and Cy3SnCH(3,5-Me(2)Pz)(2)W(CO)(4), respectively. Treatment of these heterobimetallic complexes, R3SnCH(3,5-Me(2)Pz)(2)W(CO)(4) (R-3 = (i-Pr)Ph-2, Cy-3, Et-3), with I-2 results in the formation of a novel eta(t)-bis(pyrazol-1-yl)acyl complex CHC(O)(3,5-Me(2)Pz)(2)W(CO)(3)I, with the loss of the organotin group from the methine carbon. In addition, the reaction of R3SnCH(3,5-Me(2)Pz)(2)W(CO)(4) with SnCl4 in a 1:1 molar ratio gives heterotrimetallic complexes R3SnCH(3,5-Me(2)Pz)(2)W(Cl)(CO)(3)SnCl3 (R = Cy, Et). It is unexpected that these heterotrimetallic complexes are also reactive in solution. They change to a novel four-membered heterometallacyclic complex CH(3,5-Me(2)Pz)(2)W(CO)(3)Cl in dichloromethane solution at room temperature. Furthermore, this complex can also be obtained by the selective cleavage of the W-Sn bond in complexes CH(3,5-Me(2)Pz)(2)W(CO)(3)SnAr3 with SnCl4.