Atomic complexities

In the internal region r> a, the electron-atom complex behaves almost as a bound state so that a configuration... 

In view of the lack of a simple valence relation between the atoms, complex atom-groups may be formed in sodium cadmide in a way similar to the formation of Pt>2- ions in a solution of sodium plumbide, NaPb2, in liquid ammonia,9 preventing a simplicity of structure. 

The structure factor for the 104-atom complex with almost perfect icosahedral symmetry determines the intensities of the diffraction maxima, in correspondence with the inverse relationship between intensity in reciprocal space and the atom-pair vectors in real space that was discovered fifty years ago by Patterson.27 The icosahedral nature of the clusters in the cubic crystal explains the appearance of the Fibonacci numbers and the golden ratio. 

Compound (39) reacts with Pt(II) and Pd(II) chlorides at room temperature in CH3CN and CHC13, respectively. But in both cases coordination of two ligands with the metal atom was accompanied by nucleophilic substitution at the exocyclic carbon atom. Complexes (210) and (211) having a novel chelate bicyclic ligand with Pt(II) and Pd(II) have been formed in the course of template processes [Eq. (149)] (92IZV335,92MI1). 

In this reaction, a rhodium atom complexed to a chiral diphosphine ligand ( P—P ) catalyzes the hydrogenation of a prochiral enamide, with essentially complete enan-tioselectivity and limiting kinetic rates exceeding hundreds of catalyst turnovers per second. While precious metals such as Ru, Rh, and Ir are notably effective for catalysis of hydrogenation reactions, many other transition-metal and lanthanide complexes exhibit similar potency. 

A unique Pd(II)-promoted ortfto-esterification of 2,5-diphenyloxazole has been described [26], When 2,5-diphenyloxazole was heated with 2.5 equivalents of Pd(OAc>2 in acetic acid and CCLt, regioselective palladation took place, giving rise to arylpalladium(n) o-complex 31 in almost quantitative yield. The regioselectivity observed reflects the strong coordination ability of the oxazole nitrogen atom to the palladium atom. Complex 31 was then dissolved in MeOH-THF (1 1) and the solution was stirred at 0 °C to produce 2-(5 -phenylthiazol2-yl)-benzoate 32. A... 

Loeb, P, Nuclear Culture Living and Working in the World s Largest Atomic Complex. Coward, McCann Geoghegen, New York, 1982. 

C -C, on platinum-silica, 30 352 chain termination bed residence time, 39 255-256 probability, CO pressure effects, 39 258 chemical mechanisms for reactions with deuterium, on chromia, 20 73-84 chemisorption, carbon atom complexes, 32 167-167, 175-176 coupling, 27 235-238 double, 27 238, 239 cracking, 39 283 cyclic, catalysis of, 20 309-311 cyclization, 28 295 degree of strain, 25 135 dehydrogenation of, 19 88, 89 deuteration of, 25 140, 141 dimerization, 20 304... 

Lipids A class of organic compounds composed of carbon, hydrogen, and oxygen atoms. Complex lipids contain fatty acids attached to a backbone molecule such as glycerol. Simple lipids, such as carotene, are polymers of terpene. Lipids are used in organisms for energy storage. 

A careful inspection of several examples [51-54] leads to the conclusion that the O-coordination is produced trans to a soft (C or P) atom, while C-coordi-nation mainly occurs trans to a harder (N) atom. Complex (12) is the paradigm of this selectivity on bonding modes and sites [53] the C-bonded yhde is found trans to the N atom while the N-bonded ylide is trans to the paUadated C atom. In spite of this puzzling appearance (Scheme 5), the consideration of the nature of the donor atoms and the antisymbiotic behavior of the Pd center [55] provides a sensible explanation of the observed reactivity [21]. 

A nonplanar and less stable (by 14.5 kcal/mol, compared to that formed at the N3 atom) complex is formed by anchoring at the Ne atom. 

First, a mechanism without solvent molecnles was examined for simplification and initial formation of a carbonyl-Mg atom complex was expected. The previonsly proposed polar addition mechanism is shown in Scheme 12, which has been quoted widely. ... 

Two Carbon Atom Complexes Formed upon Olefin Chemisorption... 

Atomic clustering or atomic complex formation in materials can also... 

Interesting line narrowing has been observed of quadrupole-induced lines of hydrogen-rare gas mixtures. These have been explained by van Kranendonk and associates [428] in terms of the mutual diffusion coefficient of H2 in a rare-gas environment, as an effective lengthening of the interaction times of H2-atom complexes. 

All of the complexes structurally characterized have either a square planar or a square pyramidal structure with a planar arrangement of the four donor atoms. Complexes having general formulas [NiL]Y2 and [NiXL]Y (L = quadridentate ligand X = coordinated anion Y = uncoordinated anion) are invariably low-spin as one can easily predict on the basis of the high nucleophilicity of the donor atoms.1389... 

There is a large body of information on complexes of pyridine, substituted pyridines and ligands containing pyridine rings and other donor atoms. Complexes with pyridine and its derivatives have been reviewed. 70,9 15,1468c h... 

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