Metal-ions linked surface-confined molecular dyads of Zn-porphyrin–metallo-terpyridine: an experimental and theoretical study

• Published in: RSC advances Vol. 7; no. 3; pp. 1290 - 1298
• Main Authors: Gera, Bhawna, Manna, Arun Kumar, Chandra Mondal, Prakash
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 01.01.2017
• Subjects: Absorption; Atomic force microscopy; Banded structure; Charge transfer; Copper; Covalence; Density functional theory; Electronic structure; First principles; Mathematical analysis; Metallography; Organic chemistry; Palladium; Silicon dioxide; Substrates; Time dependence; Zinc
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c6ra25090d

Covalently-assembled monolayers of functionalized Zn-porphyrin complex (5,10,15,20- tetra (4-pyridyl)-porphyrin, Zn-TPyP) are employed as the template layer for fabricating heterogeneous molecular dyads composed of opto-active metallo-terpyridyl complexes on SiO x substrates. Metallo-linkers such as Cu 2+ and Pd 2+ are exploited to connect the Zn-porphyrin template layer with the metallo-terpyridyl complexes (M–PT, M = Fe 2+ , Ru 2+ , Os 2+ , while PT = 4′-pyridyl terpyridyl) using a wet chemical “layer-by-layer” (LBL) technique. Formation of both the template and dyad layers over the SiO x substrates were probed by atomic force microscopy (AFM) and UV-vis absorption techniques. The molecular films were used for comparison and to study the effect of different metallo-linkers based on the changes in the characteristics of the Soret bands of Zn-TPyP and the metal-to-ligand charge-transfer (MLCT) bands of terpyridyl complexes. Besides, detailed electronic structure calculations based on first-principles density functional theory (DFT) and time-dependent DFT (TDDFT) have been performed for understanding experimentally observed photophysical properties of the surface-confined dyads.