D centre

Intramolecular reactions between donor and acceptor centres in fused ring systems provide a general route to bridged polycyclic systems. The cts-decalone mesylate given below contains two d -centres adjacent to the carbonyl function and one a -centre. Treatment of this compound with base leads to reversible enolate formation, and the C-3 carbanion substitutes the mesylate on C-7 (J. Gauthier, 1967 A. Belanger, 1968). 

Apollo Tyres Ftd., R D Centre Fimda, Gujarat, India... 

Mintz, M., Molburg, J., Folga, S. and Gilette, J. (2002). Hydrogen Distribution Infrastructure. Research paper. Argonne Argonne National Laboratory, Transportation Technology R D Centre. 

R D Centre, Indian Oil R D Centre, Sector-13, Faridabad, India... 

Available from Cerestar, EBS Vilvoorde R D Centre, Centre of Expertise Fermentation, Havenstraat 84, 1800 Vilvoorde, Belgium Mitsubishi Chemical Corporation, Specialty Chemicals Company, Intermediate Chemicals Department, 5-2 Marunouchi 2-chome, Chiyoda-ku, Tokyo 100-0005, Japan or Nikken Chemicals Co., Ltd., Development Department, Sumitomo-Tsukiji Bldg., No. 4-14, Tsukiji 5-chome, Chuo-ku, Tokyo 104-0045, Japan. 

Robert D., Centre d Etudes Nucleates de Grenoble, DRF-Laboratoires de Chimie, 85X, F-38041 Grenoble, France Rolando C., Department de Chimie, Ecole Normale Superieure, 24 rue Lhamond, F-75231 Paris, France Saka S., Department of Wood Science and Technology, Faculty of Agriculture, Kyoto University, Kitashirawaka Oiwake-Cho, Sakyo-ku, Kyoto 606, Japan... 

DANIEL ROCHU, Sci D Centre de Recherches du Service de Sante des Armees, La Tronche, France... 

With this background, the present work is initiated at the Indian Oil Corporation R D Centre. The broad objectives of this work are as given below. 

Different grades of pyrolysis oil were burned at 4 MW nominal power output in a test furnace of Oilon Oy s R D Centre. Operation, dimensions, adjustment parameters, and characteristics of pyrolysis oils were tested and compared, and ertussions in different cases were measured. 

These [4Fe-4S] clusters (P clusters) from the MoFe protein differ from normal [4Fe-4S] clusters, as demonstrated by MCD and Mossbauer measurements. The P clusters contain three iron atoms (D atoms) which differ from the fourth. In the MoFe protein from A vinelandii the minor component of the P cluster appears to be a high-spin Fe in a tetrahedral sulfur environment. The D centres also appear to be Fe in the resting enzyme, giving an unusually reduced level for the cluster. As all four iron atoms are Fe , the Mossbauer evidence for two types of iron atom in ratio 3 1 may be interpreted in terms of variation in the non-sulfide ligands, although other explanations are possible. 

POSITIVE c.d. centred near 390 nm NEGATIVE c.d. centred near 390 nm... 

Figure 8.15. Configuration coordinate diagram for the formation of a D -D pair. Exchange of an electron between two D centres to give a D -D pair at the same configuration costs the Hubbard energy U. The D -D centers subsequently relax to a different configuration and the overall energy is lowered by the effective correlation energy t/eff-...

Stokes shift. Another possibility is that the optical excitation occurs from a negatively charged (D ) gap state to a D gap state, where there is initial non-radiative loss of energy to a stable D configuration. Photoluminescent emission takes place bringing the electron back to the D centre. This is illustrated in Figure 8.16 schematically. This type of... 

Fig 6.5 Representation of the 2D type constraining potential energy left, the potential energy as a function of the polar angle d centre, a representation of the potential energy function as a cut in the Acz-plane right, the three-dimensional representation of the potential in polar coordinates. 

The first spectroscopic evidence of the presence of (S,H) and (S,D) centres in hydrogenated S-doped silicon was actually provided by Love et al. [155] in a study of spectral hole burning in the 2po and 2p lines of the (S, H)c2 and (S, H)c3 spectra inhomogeneously broadened in Si0.999Ge0.001 alloy samples. 

Equations 12-16 permitted one also to rationalize11 the large inverse D KIE in the epoxidation of ethylene and their dependence on the inlet gas mixture. Since in the epoxyethane formation no C—H bond rupture takes place, the observed D KIEs are caused by the changes in the chemical composition of the surface layer of the catalyst controlling the catalytic reaction. In the presence of C2D4 the deep oxidation is slowed down, the concentration of [Ag2Os] centres and subsequently also the [Ag + (0 d)] centres increases and this results in the increase of the observed production of C2D40. 

R. Wagner EXIDE Technologies Network Power R D Centre D-63654 Btidingen, Germany E-mail rainer.wagner exide.de... 

P. Joshi, Nestle Research Centre, Lausanne and C. J. B. Brimelow, Nestle R D Centre, Shanghai... 

Dr Christopher Brimelow Nestle R D Centre Shanghai China... 

The Pt2S2 core is formally coordinatively and electronically saturated since the 16-electron d centre is effectively stable to addition reactions. However, upon metallation, it is possible to introduce unsaturation to the system when the metal carries along a labile ligand such as cycloocta-1,5-diene (cod). This is exemplified in the synthesis of [Pt3(cod)(PPh3)4( 3-S)2] and [Pt2Pb-(N03)2(PPh3)4(/i3-S)2]. This transformation from a Lewis basic to a Lewis acidic complex is accompanied by alteration of its chemical reactivity and coordination... 

The effect of the exponential factor is to make the volume of the ion inaccessible to solvent molecules, i.e., to exclude a sphere of radius d centred on the ion from all h three-dimensional integrations, initially extended to the whole volume V. This results from the fact that the interactions are functions of relative distances measured from the centres of the particles involved. The effect of volume exclusion, can be dealt with in a systematic way by introducing the Mayer functions... 

Fs (D) centres are analogues to Fs (H) centres but obtained by irradiation in D2 atmosphere. The hyperfine interaction of the trapped electron with the deuteroxyl D nucleus (1=1) leads to an unresolved triplet due to the small magnetic moment of deuterium. The comparison between the N2" signal obtained by adsorption of N2 on Fs (D) centres reveals that each of the main lines in the N2 spectrum (Fig 3a) are split into doublets in the case of N2 formed over the Fs (H) centres (Fig 3b). This weak superhyperfme splitting of less than 1 Gauss indicates that a single proton (I = 1/2) interacts with the N2 radical, and this proton... 

Photoluminescent emission takes place bringing the electron back to the D centre. This is illustrated in Figure 8.16 schematically. This type of... 

Department of Chemistry, University of Durham, Durham, UK b Laboratoire Chimie des Surfaces, ESA 7069, Universite P. et M. Curie, Paris, France c SINTEF Applied Chemistry, Blindern, Oslo, Norway d Statoil A/S R D Centre, Rotvoll, Trondheim, Norway... 

The vanadate moieties are made up of 5-coordinate vanadyl centres which link together via [VjOj] rings. In general the oxidation state of vanadium is 4-I-, although some mixed 4+/5+ clusters have been found. Since V4-i- is a d centre the arrangement of the cluster d -electrons is of interest both from the point of view of cluster bonding and also for the molecular magnetism found in these compounds. 

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