Complexes structural chemistry

Progress in zeolite crystallization in the last several years has been mostly in the experimental realm and has resulted in several new synthetic zeolites and compositional variants of previously known structures. Theoretical advances have come more slowly but are significant. Until the elucidation of zeolite structures in the last decade or so, structural interpretation of crystallization phenomena was not possible. As additional physical and chemical techniques are applied to the complex structural chemistry of zeolite crystallization, our understanding of the mechanism increases, and the extent of empiricism in synthesis decreases. Areas of investigation still unexplored that should add considerable understanding... 

These multiple roles operate in parallel with a complex structural chemistry giving rise to families of chemically vastly different modifications of the element. It is a special characteristic of carbon chemistry that many of these modifications cannot be obtained as phase-pure materials. This limits the exact knowledge ol physical and chemical properties to a few archetype modifications, namely graphite and diamond. 

Carbohydrate-Metal Complexes Structural Chemistry of Stable Solution Species... 

The Group IVA metals have no important aqueous ionic chemistry but form ions in crystalline oxy-compounds. Bismuth can perhaps be grouped with Ti, Zr, and Hf it has a strong tendency to form hydroxy-complexes, but salts such as Bi(N03)3. 5 H2O, M3 [Bi(N03)6] 2 24 H2O, and 812(804)3 presumably contain Bi ions. It seems reasonable to put Ga(iii), In(iii), Tl(iii), and Sn(ii) in this group the complex structural chemistry of these elements is outlined in Chapter 26. 

We have seen that ions XO3 cannot balance the e.b.s. of an 8-coordinated ion M without rearranging the anionic charge and behaving as either bidentate or bridging ligands. For an ion such as SO4 the possible types of behaviour are more numerous and are rather completely illustrated by the structures of Zr(S04)2 and its hydrates. This compound has an unexpectedly complex structural chemistry, for... 

The only nonmetallic element in group 13 (see Topic B2). boron has a strong tendency to covalent bonding. Its uniquely complex structural chemistry arises from the (2s) (2p) configuration, which gives it one less valence electron than the number of orbitals in the valence shell. Simple compounds such as BC13 have an incomplete octet and are strong Lewis acids (see Topics CT and C9), but boron... 

There is an extensive and complex structural chemistry of boron-oxygen anionic species (polyborates), in aqueous or nonaqueous solution and in the melt or solid state, Six-membered ring formation dominates, but the structural chemistry of the species is complicated since boron exists in either 3- or 4-coordinate environments, or various combinations of these. Thus most polymeric species consist of (6—0)3 rings joined by boron atoms linked to an intervening oxygen atom, or y rings sharing a common boron atom. 

Boron (like silicon) invariably occurs in nature as 0X0 compounds and is never found as the element or even directly bonded to any other element than oxygen. The structural chemistry of B-O compounds is characterized by an extraordinary complexity and diversity which rivals those of the borides (p. 145) and boranes (p. 151). In addition, vast numbers of predominantly organic compounds containing B-O are known. 

The structural chemistry of Sn halides is particularly complex, partly because of the... 

Structural chemistry of pyridonate complexes of late 3d metals 97ACR89. 

Hilgenfeld, R., Saenger, W. Structural Chemistry of Natural and Synthetic Ionophores and their Complexes with Cations, in Topics in Current Chemistry (ed. Boschke, F. L.), p. 8, Berlin—Heidelberg—New York, Springer 1982... 

Raymond, K. N., Muller, G., and Matzanke, B. F. Complexation of Iron by Siderophores A Review of Their Solution and Structural Chemistry and Biological Function. 123 49-102 (1984). 

Tantalum powder is produced by reduction of potassium heptafluoro-tantalate, K2TaF7, dissolved in a molten mixture of alkali halides. The reduction is performed at high temperatures using molten sodium. The process and product performance are very sensitive to the melt composition. There is no doubt that effective process control and development of powders with improved properties require an understanding of the complex fluoride chemistry of the melts. For instance, it is very important to take into account that changes both in the concentration of potassium heptafluorotantalate and in the composition of the background melt (molten alkali halides) can initiate cardinal changes in the complex structure of the melt itself. 

Structural chemistry of natural and synthetic ionophores and their complexes with cations. R. Hil-genfeld and W. Saenger, Top. Curr. Chem., 1982,101,1-82 (346). 

Complexation of iron by siderophores. A review of their solution and structural chemistry and biological function. K. N. Raymond, G. Muller and B. F. Matzanke, Top. Curr. Chem., 1984,123, 49 (227). 

ET-IR spectroscopy was employed to investigate the structures of the 1 1 complexes between Li" and the guanidine-substituted azo compounds pyiidine-2-azo-p-phenyltetramethylguanidine and 4,4 -bis(tetramethylguanidine)azoben-zene. Both Li" complexes exist as dimers in acetonitrile solution.The structural chemistry of potassium N,N -di(tolyl)formamidinate complexes has been investigated in detail. These compounds were prepared by deprotonation of the parent Af,N -di(tolyl)formamidines with potassium hydride (Scheme 13). The resulting adducts with either THE or DME display one-dimensional polymeric solid-state structures that exhibit /r-fj fj -coordinated formamidinates. 

Structural Chemistry of Organo-Transition Metal Complexes, 5, 93... 

Over the last decade, the chemistry of the carbon-carbon triple bond has experienced a vigorous resurgence [1]. Whereas construction of alkyne-con-taining systems had previously been a laborious process, the advent of new synthetic methodology based on organotransition metal complexes has revolutionized the field [2]. Specifically, palladium-catalyzed cross-coupling reactions between alkyne sp-carbon atoms and sp -carbon atoms of arenes and alkenes have allowed for rapid assembly of relatively complex structures [3]. In particular, the preparation of alkyne-rich macrocycles, the subject of this report, has benefited enormously from these recent advances. For the purpose of this review, we Emit the discussion to cychc systems which contain benzene and acetylene moieties only, henceforth referred to as phenylacetylene and phenyldiacetylene macrocycles (PAMs and PDMs, respectively). Not only have a wide... 

Mohamed, A.A., Abdou, H.E. and Fackler, J.P. Jr (2006) Mercury(ll) cyanide coordination polymer with dinuclear gold (1) amidinate. Structure of the 2-D [Au2(2,6-Me2-formamidinate)2]-2Hg (CN)2 2THF complex. Inorganic Chemistry, 45, 11-12. 

Mansour, M.A., Lachicotte, R.J., Gysling, H.J. and Eisenberg, R. (1998) Syntheses, molecular structures, and spectroscopy of gold(III) dithiolate complexes. Inorganic Chemistry, 37, 4625. 

---