Substituent effects in the tricarbonylcyclobutadieneiron system
Abstract
Proton n.m.r. spectra of twenty-one substituted tricarbonylcyclobutadieneiron complexes in deuteriochloroform reveal that a substituent modifies electron density at the ring positions adjacent to it in much the same fashion as a substituent in the benzene system. A substituent has a significant influence on electron density at the carbon atom directly across the ring.