Molecular properties clustering

Downs G M, P Willett amd W Fisanick 1994. Similarity Searching and Clustering of Chemical-Stnictur Databases Using Molecular Property Data. Journal of Chemical Information and Computer Scienc 34 1094-1102. 

Oxide- and Zeolite-supported "Molecular" Metal Clusters Synthesis, Structure, Bonding, and Catalytic Properties... 

Abstract This review is a summary of supported metal clusters with nearly molecular properties. These clusters are formed hy adsorption or sirnface-mediated synthesis of metal carbonyl clusters, some of which may he decarhonylated with the metal frame essentially intact. The decarhonylated clusters are bonded to oxide or zeolite supports by metal-oxygen bonds, typically with distances of 2.1-2.2 A they are typically not free of ligands other than the support, and on oxide surfaces they are preferentially bonded at defect sites. The catalytic activities of supported metal clusters incorporating only a few atoms are distinct from those of larger particles that may approximate bulk metals. 

Gates BC (2005) Oxide- and Zeolite-supported Molecular Metal Clusters Synthesis, Structure, Bonding, and Catalytic Properties. 16 211-231 Gibson SE (nee Thomas), Keen SP (1998) Cross-Metathesis. 1 155-181 Gisdakis P, see Rosch N (1999) 4 109-163 Gdrling A, see Rosch N (1999) 4 109-163... 

A structural classification of 8 is difficult due to the fact that an arrangement of metal atoms as in 8 is uncommon in the whole field of molecular metal clusters. For this reason, detailed understanding of the bonding properties in 8 requires quantum chemical calculations. Theoretical analysis seems to be especially applicable to learning more about the bond between the two tetrahedra, which appears at first to be an isolated metal-metal bond between two metal atoms in the formal oxidation state zero. 

The extraordinary bonding properties in 16 can also be seen in a diagram of 16 (Fig. 34). In 16, an almost perfect five-numbered axis is attained, distorted only by the central Ga2 unit. This is the first time that a symmetry close to the five-numbered symmetry is observed for molecular metalloid clusters. A few solid-state modifications with five-numbered symmetry have, however, been found for compounds involving Group 13 elements. Because there is no crystallographic space group with a five-numbered axis, these compounds are summarized under the collective name quasi-crystals .83 For a better understanding of quasi-crystals,... 

The Periodic Table forms one of the most remarkable, concise, and valuable tabulations of data in science. Its power lies in the regularities that it reveals, thus, in some respects, it has the same role as the SOM. Construct a SOM in which the input consists of a few properties of some elements, such as electronegativity, atomic mass, atomic radius, and electron affinity. Does the completed map show the kind of clustering of elements that you would expect What is the effect of varying the weight given to the different molecular properties that you are using ... 

J. D. Watts, G. W. Trucks, and R. J. Bartlett, The unitary coupled-cluster approach and molecular properties. Applications of the UCC(4) method. Chem. Phys. Lett. 157, 359-366 (1989). 

Rapid convergence of molecular properties with respect to the excitation rank is obtained with the systematic approximations of coupled-cluster (CC) theory... 

The single-reference coupled cluster (CC) theory [1-5] has become a standard computational tool for studying ground-state molecular properties [6-10]. The basic approximations, such as CCSD (coupled cluster singles and doubles approach) [11-15], and the noniterative CCSD[T] [16,17] and CCSD(T) [18] methods, in which the cleverly designed corrections due to... 

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