Self-assembly of a metal-ion-bound monolayer of trigonal connectors on mercury: an electrochemical Langmuir trough.
The adsorption of the trigonal connector, 1,3,5-tris[10-(3-ethylthiopropyl)dimethylsilyl-1,10-dicarba-closo-decaboran-1-yl]benzene (1), from acetonitrile/0.1 M LiClO(4) on the surface of mercury at potentials ranging from +0.3 to -1.4 V (vs. aqueous Ag/AgCl/1 M LiCl) was examined by voltammetry, Langmuir isotherms at controlled potentials, and impedance measurements. No adsorption is observed at potentials more negative than approximately -0.85 V. Physisorption is seen between approximately -0.85 and 0 V. At positive potentials, adsorbate-assisted anodic dissolution of mercury occurs and an organized surface layer is formed. Although the mercury cations are reduced at -0.10 V, the surface layer remains metastable to potentials as negative as -0.85 V. Its surface areas per molecule and per redox center are compatible with a regular structure with the connectors 1 woven into a hexagonal network by RR'S-->Hg(2)(2+)<--SRR' or RR'S-->Hg(2+)<--SRR' bridges. The structure is simulated closely by geometry optimization in the semiempirical AM1 approximation.
Varaksa
Natalia
N
Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0215, USA.
Pospísil
Lubomír
L
Magnera
Thomas F
TF
Michl
Josef
J
D000097:Acetonitriles / Q000737:chemistry; D000327:Adsorption; D002412:Cations; D004563:Electrochemistry; D007477:Ions; D018020:Lithium Compounds / Q000737:chemistry; D046911:Macromolecular Substances; D008628:Mercury / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010472:Perchlorates / Q000737:chemistry; D012984:Software
D000097:Acetonitriles; D002412:Cations; D007477:Ions; D018020:Lithium Compounds; D046911:Macromolecular Substances; D008670:Metals; D010472:Perchlorates; D008628:Mercury; C054684:lithium perchlorate; C032159:acetonitrile