Pentamethylcyclopentadienyl rhodium dichloride dimer

The compound has idealized C2h symmetry. Each metal centre is pseudooctahedral. The compound is prepared by the reaction of rhodium trichloride trihydrate and pentamethylcyclopentadiene in hot methanol, from which the product precipitates: : It was first prepared by the reaction of hydrated rhodium trichloride with hexamethyl Dewar benzene Image:Hexamethyl Dewar benzene reacting with rhodium chloride under acidic conditions.PNG|left|thumb|394px|Synthesis of [Cp*RhCl2]2 using hexamethyl Dewar benzene. This complex was first prepared from hexamethyl Dewar benzene and RhCl3(H2O)3. This rhodium(III) dimer can be reduced with zinc in the presence of CO to produce the rhodium(I) complex [Cp*Rh(CO)2]. ==Reactions==

Reductive carbonylation gives [Cp*Rh(CO)2]. The Rh-μ-Cl bonds are labile and cleave en route to a variety of adducts of the general formula Cp*RhCl2L. Treatment with silver ions in polar coordinating solvents causes precipitation of silver(I) chloride, leaving a solution containing dications of the form [Cp*RhL3]2+ (L = H2O, MeCN). The chemistry is similar to that of the analog pentamethylcyclopentadienyl iridium dichloride dimer. ==References==

• • • • • {{cite book|title = Synthetic Methods of Organometallic and Inorganic Chemistry – Volume 1: Literature, Laboratory Techniques, and Common Starting Materials|year = 1996|editor1-first = Wolfgang A.|editor1-last = Herrmann|editor2-first = Albrecht|editor2-last = Salzer|publisher = Georg Thieme Verlag|isbn = 9783131791610|chapter = Bis{(μ-chloro)[chloro(η-pentamethylcyclopentadienyl)rhodium]} — {Rh(μ-Cl)Cl[η-C5(CH3)5]}2|first1 = Wolfgang A.|last1 = Herrmann|first2 = Christian|last2 = Zybill|pages = 148–149|chapter-url = https://books.google.com/books?id=dlGGAwAAQBAJ&pg=PA148}} •