Langmuir−Blodgett Films of Bis(octakispropyloxy) Samarium Bisphthalocyanine. Spectroscopic and Gas-Sensing Properties

In this work, the synthesis of a novel substituted bisphthalocyanine, the bis[octakis(propyloxy)phthalocyaninato] samarium(III) complex, is reported. Langmuir−Blodgett (LB) films of this compound have been prepared. The influence of the propyloxy groups in the structure of the LB films and in their spectroscopic, chemical, electrochromic, and gas-sensing properties has been evaluated. The π−A isotherms exhibit greater monolayer stability than that observed in the unsubstituted analogue. The compressed monolayers are easily transferred by Y-type deposition resulting in red films instead of the expected green monolayers. The LB films have been characterized spectroscopically using UV−vis, near-IR, and FTIR techniques. The UV−vis spectra show that the Q-band splits into two peaks on passing from the chloroform solution to the LB films. This is the first example of a Davydov splitting in a bisphthalocyanine compound. The Davydov splitting, which is responsible for the red color of the LB films, is characteris...