The possibility of recycling CO{sub 2} from industrial emissions and of removing some of this greenhouse gas, an environmental pollutant, is receiving increased attention. Also, the possibility of using CO{sub 2} as the starting material for the synthesis of fine chemicals provides an attractive alternative to compounds presently derived from petroleum. Efforts to convert CO{sub 2} to useful chemicals will inevitably center on transition metal catalysts. Furthermore, efforts to enhance the yield of hydrogen in water gas shift reactions are also centered on carbon dioxide interactions with transition metal catalysts. For all these reasons, a broader understanding of the organometallic chemistry of CO{sub 2} is being sought. In this article, only those compounds that can be clearly identified as having carbon dioxide bound to metal centers through carbon will be considered. Thus the discussions will not include metal formate complexes whose chemistry has been reviewed recently. Also, the discussions will not include metallocarboxylic acids or metallocarboxylate esters except where these compounds have been used as reagents for the synthesis of CO{sub 2} complexes or result from reactions of these compounds. 111 refs.

The Organometallic Chemistry of Carbon Dioxide.

The adsorption of formate and acetate from aqueous solutions at pH 3−9 onto the TiO2 rutile (110) surface was studied by ATR-FTIR spectroscopy. The spectra indicated that there was only one type of adsorbed species, and that formate and acetate were adsorbed in a similar manner. On the basis of the measured νas(COO) − νs(COO) splitting (Δνas-s) of 191 and 87 cm-1, for formate and acetate, respectively, the monodentate (ester type) binding mode could be excluded. Ab initio calculations at the Hartree−Fock level showed that for pentacoordinated TiIV, present in the (110) surface, the chelating bidentate binding mode is unstable with respect to the rearrangement to the monodentate or the bridging bidentate mode. The computed vibrational frequencies of formate and acetate adsorbed in a bridging bidentate mode onto Ti clusters with 2−5 Ti centers, representing the (110) surface, agreed with experiment and thus showed that this methodology can be used for the determination of the structures of adsorbates on, fo...

Structure and Vibrational Spectrum of Formate and Acetate Adsorbed from Aqueous Solution onto the TiO2 Rutile (110) Surface

Infrared spectra of oxalate, malonate and succinate adsorbed on the aqueous surface of rutile, anatase and lepidocrocite measured with in situ ATR-FTIR

Four anthracene based sensitizers, 3-(anthracene-9-yl)-2-cyanoacrylic acid (M1), 2-cyano-3-(10-methoxyanthracene-9-yl)acrylic acid (M2), 2-(anthracene-9-ylmethylene) malonic acid (M3), and 2-((10-methoxyanthracene-9-yl)methylene)malonic acid (M4) were designed and synthesized to understand the binding modes of anchoring groups ( and ) on the nanocrystalline TiO2(101) surface and on the efficiency of dye-sensitized solar cells (DSSCs). All four sensitizers have been fully characterized using ATR-FTIR, UV−vis, and CV. These sensitizers were tested in DSSCs using 0.05 M I2, 0.5 M 1,2-dimethyl-3-n-propylimidazolium iodide (DMPI), and 0.5 M lithium iodide (LiI) in methoxypropionitrile (MPN) redox electrolyte. The sensitizers having a monocarboxylic acid group, i.e., M1 and M2, have shown marginally higher IPCE and efficiency than M3 and M4 having dicarboxylic acid groups. To have a detailed understanding of this behavior, the adsorption and binding energies to the TiO2 surface of these dyes have been investiga...

A Combined Experimental and Computational Investigation of Anthracene Based Sensitizers for DSSC: Comparison of Cyanoacrylic and Malonic Acid Electron Withdrawing Groups Binding onto the TiO2 Anatase (101) Surface

R.J. Phillips

Papers

Diagnosis of the nature of carboxylate coordination from the direction of shifts of carbonoxygen stretching frequencies