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Current Activities

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News: Dr. F. Albert Cotton passes away February 20, 2007

Our research program derives its impetus from the exploration of how transition metals form compounds with metal-metal bonds. This leads us to examine compounds in which metal atoms form bonds of various orders within certain structural frameworks. A fascinating thing about this approach to transition metal chemistry is that, in addition to frequently yielding results of the desired type, it often leads to unexpected results involving compounds different from the original targets. We deal with virtually the entire range of metallic elements and with a vast array of main group and organic species as ligands.

At the heart of most projects in the group is synthetic chemistry aimed at making new kinds of bonds or molecules; the synthetic work carries straight into an extensive use of X-ray crystallography to identify the products and reveal their important features. Normally, each worker in the group carries out X-ray studies; our facilities (diffractometers and computational capabilities) make this feasible and efficient. In addition, virtually the whole panoply of modern physical methods comes into play, including nuclear magnetic resonance, UV-visible, infrared, CD, EPR, magnetic susceptibility measurement and photoelectron spectroscopy. Theoretical analysis by molecular quantum mechanics at several levels of rigor, up to X-SCF-SW and H-F methods, are used. In the M-M multiple bond field, our current interests are in some of the less explored areas, namely compounds containing VV, NbNb, TaTa, CoCo, RuRu, Ru=Ru, OsOs, Ir-Ir and various heteronuclear species (e.g., MoW), although we still find interesting problems involving multiple bonds between pairs of Cr, Mo, W and Re atoms. In the area of metal atom clusters, we continue to pursue the triangulo clusters of Mo and W, such as Mo₃O₄ⁿ⁺, W₃S₄ⁿ⁺ and Mo₃O₂ⁿ⁺, and cuboidal species such as Mo₄S₄ⁿ⁺ and W₄S₄ⁿ⁺. We find new and better ways to make many of these clusters, as well as introduce many sorts of ligands not previously prominent in this class of compounds. We also have found that we can make discrete cluster species of Nb and Ta that correspond to the repeat units in previously known solid state materials in which there are infinite sheet structures.

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Selected Publications

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"Reactions of TiCl₄ with Phosphines and Alkylating Reagents: an Organometallic Route to a Titanium(II) Cluster Compound," F. A. Cotton, C. A. Murillo and M. A. Petrukhina. J. Organomet. Chem. 573, 78 (1999).

"A Chain of Five Chromium(II) Atoms: A Desired Compound with an Undesired, Unsurprising, but Important Structure." F. A. Cotton, L. M. Daniels, T. Lu, C. A. Murillo and X. Wang. J. Chem. Soc., Dalton Trans. 517 (1999).

"Square and Triangular Arrays Based on Mo₂⁴⁺ and Rh₂⁴⁺ Units." F. A. Cotton, L. M. Daniels, C. Lin and C. A. Murillo. J. Am. Chem. Soc. 121, 4538 (1999).

"The Designed 'Self-assembly' of a Three-dimensional Molecule Containing Six Quadruply-bonded Mo₂⁴⁺ Units." F. A. Cotton, L. M. Daniels, C. Lin and C. A. Murillo. Chem. Comm. 841 (1999).

"First paddlewheel complex with a doubly-bonded Ir₂⁶⁺ core." F. A. Cotton, C. A. Murillo and D. J. Timmons. Chem. Commun. 1427 (1999).