Scanning tunneling microscopy of dimeric and polymeric products of electroreduced (Re(CO) sub 3 (4-vinyl,4 prime -methyl-2,2 prime -bipyridine)Cl)

• Published in: Journal of the American Chemical Society Vol. 112:4
• Main Authors: Snyder, S.R., White, H.S., Lopez, S., Abruna, H.D.
• Format: Journal Article
• Language: English
• Published: United States 14-02-1990
• Subjects: 360102 - Metals & Alloys- Structure & Phase Studies; 400400 - Electrochemistry; CALCULATION METHODS; CARBON; CHEMICAL REACTIONS; CHEMISTRY; COMPLEXES; DATA ANALYSIS; DIMERS; ELECTROCHEMISTRY; ELECTRON MICROSCOPY; ELEMENTAL MINERALS; ELEMENTS; GRAPHITE; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; MATERIALS SCIENCE; MEASURING INSTRUMENTS; MEASURING METHODS; MICROSCOPY; MINERALS; NONMETALS; POLYMERS; REDUCTION; RHENIUM COMPLEXES; SCANNING ELECTRON MICROSCOPY; TRANSITION ELEMENT COMPLEXES
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja00160a006

Scanning tunneling microscopy (STM) was used to image adsorbed products resulting from electroreduction of (Re(CO){sub 3}(vbpy)Cl) (vbpy = 4-vinyl,4{prime}-methyl-2,2{prime}-bipyridine) on highly oriented pyrolytic graphite (HOPG). STM images, in air, of HOPG electrodes following electroreduction of (Re(CO){sub 3}(vbpy)Cl) (in acetonitrile/0.1 M tetra-n-butylammonium perchlorate) by cycling the potential between 0 and {minus}2.0 V vs a sodium saturated colomel electrode (SSCE) show molecular species uniformly distributed on the surface including approximately dumbbell shaped molecules ({approx} 40 {times} 20 {angstrom}). The size and shape of these aggregates is consistent with products derived from vinyl-vinvyl coupling of Re-Re bonded dimers: ((vbpy)(CO){sub 3}Re-Re(CO){sub 3}(vbpyH-vbpyH)(CO){sub 3}Re-Re(CO){sub 3}(vbpy)). STM images of electrodes prepared by cycling the potential between 0 and {minus}1.45 V vs SSCE (less reducing conditions) show highly nonuniform coating of the surface by polymer. Several polymer morphologies were observed with polymer nucleation preferentially occurring at step sites on HOPG.