Monolayers, Langmuir–Blodgett films of bimetallic coordination polymers of 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine

Building blocks of coordination polymers have attracted much attention because of promising applications in porous materials, molecular engineering and devices. We report here an interfacial self-assembly of bimetallic coordination polymer of Cd–Fe(pyterpy)2 (pyterpy: 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine). The surface pressure–area and area–time isotherms indicated that stable monolayers of Fe(pyterpy)2(BF4)2 could be formed on the 0.1 mol/l CdCl2 subphase surface after an interfacial coordination reaction over 12 h. By using the Langmuir–Blodgett (LB) method, monolayers of the Cd–Fe(pyterpy)2 coordination polymer were transferred on the substrate surfaces, and characterized by using the UV–vis absorption and X-ray photoelectron spectroscopy, as well as transition electron microscopy. The spectral data revealed that the LB film was composed of C, Cl, Cd, N and Fe elements, which was in agreement with the composition of the coordination polymer. Reversible redox wave centered at about 500 mV (vs Ag/AgCl) was recorded for the electrode modified with the LB film of the coordination polymer. The present method could be developed to prepare two- and three-dimensional nanoporous building blocks containing two metal ions.