Strategies for Electrooptic Film Fabrication.Influence of Pyrrole-Pyridine-Based Dibranched Chromophore Architecture on Covalent Self-Assembly,Thin-Film Microstructure,and Nonlinear Optical Response

摘要

The new dibranched,heterocyclic "push-pull" chromophores bis{1-(pyridin-4-yl)-2-[2-(N-methyl-pyrrol-5-yl)]ethane}methane (1),1-(pyrid-4-yl)-2-(N-methyl-5-formylpyrrol-2-yl)ethylene (2),{1-(N-methyl-pyridinium-4-yl)-2-[2-(N-methylpyrrol-5-yl)]ethane}{(1-(pyridin-4-yl)-2-[2-(N-methylpyrrol-5-yl)]ethane}-methane (3),N-methyl-2-[1-(N-methylpyrid-4-yl)ethen-2-yl]-5-[pyrid-4-yl]ethen-2-yl]pyrrole iodide (4),bis-{1-(N-methyl-4-pyridinio)-2-[2-(N-methylpyrrol-5-yl)]ethane}methane iodide (5),and N-methyl-2,5-[1-(N-methylpyrid-4-yl)ethen-2-yl]pyrrole iodide (6) have been synthesized and characterized.The neutral (1 and 2) and monomethyl salts (3 and 4) undergo chemisorptive reaction with iodobenzyl-functionalized surfaces to afford chromophore monolayers SA-1/SA-2 and SA-3/SA-4,respectively.Molecular structures and other physicochemical properties have been defined by ~1H NMR,optical spectroscopy,and XRD.Thin-film characterization by a variety of techniques (optical spectroscopy,specular X-ray reflectivity,atomic force microscopy,X-ray photoelectron spectroscopy,and angle-dependent polarized second harmonic generation) underscore the importance of the chromophore molecular architecture as well as film growth method on film microstructure and optical/electrooptic response.