Synthesis, photophysics, photochemistry, electrochemistry and structural studies of luminescent rhenium(I) surfactant complexes; non-linear optical properties in Langmuir–Blodgett films

Abstract

A series of structurally related rhenium(i) tricarbonyl diimine surfactant-active complexes, [Re(CO)₃(diimine){py(CH₂)_nCH₃ }]⁺ and [Re(CO)₃(diimine){pyCO(Chol)}]⁺ have been synthesized (n=0, 1, 4, 12, 14, 16, 18; py=pyridyl, Chol=cholesteryl), and their photophysical, photochemical and electrochemical properties studied. A systematic study on the dependence of their photophysical properties in different environments has also been presented. In general, there is no apparent change in the photophysical behavior of these complexes as a function of the chain length of the surfactant type pyridyl ligands, the mechanism of which has been discussed. Langmuir–Blodgett films of the complexes have been prepared, and their π–A isotherms, together with their electronic absorption and emission properties studied. The second harmonic generation (SHG) properties of the LB films have also been investigated. The X-ray crystal structure of a surfactant rhenium(i) complex, [Re(bpy)(CO)₃(pyC₁₇H₃₅)]ClO₄ has been determined.