Synthesis and characterization of a first generation organorhenium dendrimer

A new, more efficient route to the functionalized Cp compound [η5-(C5H4)CH2CH2CH2I]Re(CO)3, (2) is reported. The reaction of 2 with [(LiC5H4)Re(CO)3] yields the new binuclear complex (CO)3Re[(η5-C5H4)(CH2)3(η5-C5H4)]Re(CO)3 (3). The crystal structure of 3 has been determined. Crystals of 3 are triclinic, space group P, with a=8.241(1) Å, b=11.154(1) Å, c=11.699(1) Å, α=106.383(10)°, β=102.512(10)o, γ=105.067(10)°, Z=2 and R=0.045. Compound 2 has also been used to build up a first generation organometallic dendrimer containing six rhenium units by the convergent method.