Pentamethylcyclopentadienyl rhodium dichloride dimer
Pentamethylcyclopentadienyl rhodium dichloride is an organometallic compound with the formula 2, commonly abbreviated 2 This dark red air-stable diamagnetic solid is a reagent in organometallic chemistry.Structure and preparation
The compound has idealized C2h symmetry. Each metal centre is pseudo-octahedral.
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 2 using hexamethyl Dewar benzene.Reactions
Reductive carbonylation gives .
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 chloride, leaving a solution containing dications of the form 2+.
The chemistry is similar to that of the analog pentamethylcyclopentadienyl iridium dichloride dimer.
