Preparation of Photoreactive Oligomers by ADMET Polymerization of [(C5H4(CH2)8CH═CH2)Mo(CO)3]2

Abstract

Polymerization of the [(η5-C5H4(CH2)8CH═CH2)Mo(CO)3]2 complex by acyclic diene metathesis polymerization (ADMET) is reported. The polymerization reactions were performed using Schrock’s catalyst, which resulted in formation of a polydisperse oligomer (Mn = 2300 and Mw/Mn = 4.3) with Mo−Mo bonds in the oligomer chain. Under dilute solvent conditions, the reaction was shown to favor the formation of the ring-closing metathesis (RCM) product. The ADMET oligomer was photochemically degradable, and irradiation with λ > 520 nm light in CCl4 resulted in cleavage of the oligomer backbone and formation of the metal chloride complex [μ-C5H4(CH2)8CH═CH(CH2)8C5H4{Mo(CO)3Cl}2]. The RCM product was also irradiated and the photochemical product is identical to that formed by irradiation of the oligomer. Copolymerization of [(η5-C5H4(CH2)8CH═CH2)Mo(CO)3]2 with 1,9-decadiene using Grubbs’ second-generation catalyst resulted in a higher molecular weight oligomer (Mn = 3400, Mw/Mn = 3.9).