Structural coordination chemistry

It is quite clear that knowledge obtained from the study of equilibrium states may be applied to mechanistic problems only in a very restricted sense. Nevertheless it is surprising that the choice of chiral auxiliary reagents for synthesis seems seldom to be influenced by considerations of structural coordination chemistry. It must be mentioned that such reactions are often carried out in a medium not familiar to the coordination chemist. ... 

B. F. Matzanke, Structures, Coordination Chemistry and Functions of Microbial Iron Chelates, in Handbook of Microbial Iron Chelates , ed. G. Winkehnann, CRC Press, Boca Raton, FL, 1991, p. 15. 

Biologically Relevant Structural Coordination Chemistry of Simple Lanthanide Ion Complexes... 

Early structural coordination chemistry. In Coordination Chemistry A Century of Progress (ACS Symposium Series No. 565), George B. Kauffman, ed., American Chemical Society, Washington, DC, (1994), pp. 69-72. 

This thesis contributes to the knowledge of catalysis in water, us it describes an explorative journey in the, at the start of the research, unh odded field of catalysis of Diels-Alder reactions in aqueous media. The discussion will touch on organic chemistry, coordination chemistry and colloid chemistry, largely depending upon the physical-organic approach of structural variation for the elucidation of the underlying mechanisms and principles of the observed phenomena. 

The synthesis, structural characterization and coordination chemistry of polyselenides, Se, and polytellurides, Te t , is a burgeoning field which has sprung into prominence during the past decade. The seminal studies by E. Zintl and his... 

Very recently, the coordination chemistry of low valent silicon ligands has been established as an independent, rapidly expanding research area. With the discovery of stable coordination compounds of silylenes [35-38], a major breakthrough was achieved. Within a short time a variety of stable complexes with a surprising diversity of structural elements was realized. Besides neutral coordination compounds (A, B) [35, 36, 38], and cationic compounds (C) [37], also cyclic bissilylene complexes (D) [39,40] exist. A common feature of the above-mentioned compounds is the coordination of an additional stabilizing base (solvent) to the silicon. However, base-free silylene complexes (A) are also accessible as reactive intermediates at low temperatures. 

Structural aspects and coordination chemistry of metal porphyrin complexes with emphasis on axial ligand binding to carbon donors and mono- and di-atomic nitrogen and oxygen donors. P. D. Smith, B. R. James and D. H. Dolphin, Coord. Chem. Rev., 1981,39, 31-75 (170). 

Organocobalt B models axial ligand effects on the structure and coordination chemistry of coba-loximes. N. Bresciani-Pahor, M. Forcohin, L. G. Marzilli, L. Randaccio, M. F. Summers and P. J. Toscano, Coord. Chem. Rev., 1985, 63,1 (263). 

AT-Heteroaryl ring systems are well-known as bridging functions between transition metal centers [12, 40, 41]. The pyridyl substituent is one of the representative examples of such systems that has been a widely used ligand in transition metal coordination chemistry [42]. However, the interest in group 13 metal chemistry of these ligands is of recent interest. Stalke et al. [43] have reported the synthesis and structure of the aluminum adduct Me3Al(/r-Py)PPy2 10. 

The diazaphosphane or aminoiminophosphane ligands with a NPN framework are another subclass of cyclophosphazenes. These compounds with both phosphorus in oxidation state (111) [104-110] and (V) [111-112] have been employed in the synthesis of four membered heterocycles and coordination chemistry with group 13 derivatives. Several complexes of trivalent phosphorus derivatives with both aluminum halide and alkyls are known as illustrated for 48 in Scheme 21 [113-119]. The structure determination of 48 confirms the formation of a four membered metallacycle [116, 117],... 

The finding of preparatively available iminoboranes RB = NR some years ago opened exciting new possibilities not only in B—N chemistry, but also in coordination chemistry. The first examples of iminoborane-transition-metal complexes have now been published. The structurally completely characterized t-BuB = NBu-t adds, like its alkyne analog, to the 03(00)5 fragment as a bridging ligand. When Co2(CO)g and t-BuB = NBu-t are dissolved in pentane at 0°C, warming to RT and evaporation of unreacted iminoborane yields (t-BuBNBu-t)Co2(CO)5 (86%) as a black solid, which can be recrystallized from ether-nitromethane (1 3) ... 

During the last year several new journals have appeared, in which papers of interest to organometallic chemists are published. Apart from thtjournal of Coordination Chemistry, which deals with general aspects of the chemistry of complex compounds, vehicles for preliminary communication in the area of synthesis and structure determination have commenced. A detailed breakdown of these, and of the volumes of the Elsevier journals in organometallic chemistry are given. 

Kimura, E., Kurogi, Y, Koike, T., Shionoya, M. and litaka, Y. (1993) Gold (Ill)-cyclam complexes. X-ray crystal structure and a useful macrocydic effect on the reduction of gold(III). Journal of Coordination Chemistry, 28, 33. 

Afanasyeva, V.A. and Mironov, I.V. (2001) Gold(III) macrocydic complexes in aqueous solution. Russian Journal of Coordination Chemistry, 27, 878 Afanasyeva, V.A., Glinskaya, L.A., Klevtsova, R.E. and Sheludyakova, L.A. (2005) Crystal and molecular structure of [Au(CuH24N4)][H30](C104)4. Joumal of Structural Chemistry, 46, 131. 

Melnik, M. and Parish, R.V. (1986) Classification and analysis of gold compounds on the basis of their x-ray structural and mdssbauer spectroscopic data. Coordination Chemistry Reviews, 70, 157-257. 

Here we mention as an example that in the coordination-chemistry field optical MMCT transitions between weakly coupled species are usually evaluated using the Hush theory [10,11]. The energy of the MMCT transition is given by = AE + x- Here AE is the difference between the potentials of both redox couples involved in the CT process. The reorganizational energy x is the sum of inner-sphere and outer-sphere contributions. The former depends on structural changes after the MMCT excitation transition, the latter depends on solvent polarity and the distance between the redox centres. However, similar approaches are also known in the solid state field since long [12]. 

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