Hydrogen-bond complexes structure

The bent quasi-7i C—C bond of 1 is capable of forming different types of intra- and intermolecular bonding, e.g. it may serve as proton acceptor in hydrogen-bonded complexes. Structural characteristics of the complexes have been obtained from their MW spectra. 

Fig. 1. The structure of gas hydrates containing a hydrogen-bonded framework of 46 water molecules. Twenty molecules, arranged at the comers of a pentagonal dodecahedron, form a hydrogen-bonded complex about the comers of the unit cube, and another 20 form a similar complex, differently oriented, about the centre of the cube. In addition there are six hydrogen-bonded water molecules, one of which is shown in the bottom face of the cube. In the proposed structure for water additional water molecules, not forming hydrogen bonds, occupy the centres of the dodecahedra, and...

Complexes. The structure of an n a charge-transfer complex between quinoxaline and two iodine atoms has been obtained by X-ray analysis and its thermal stability compared with those of related complexes. The hydrogen bond complex between quinoxaline and phenol has been studied by infrared spectroscopy and compared with many similar complexes. Adducts of quinoxaline with uranium salts and with a variety of copper(II) alkano-ates have been prepared, characterized, and studied with respect to IR spectra or magnetic properties, respectively. 

Jeong, H. Y., Han, Y., Comment on A Computational Study of the Structures of Van der Waals and Hydrogen Bonded Complexes of Ethene and Ethyne Chem. Phys. Lett., 263, 345. 

The discussions of Sects. 3.1,3.2 and 3.3 are structured by reference to a set of rules that were proposed some years ago [103,104] for rationalising the angular geometries of hydrogen-bonded complexes of the type B- -HX, where X is a halogen atom. These rules are as follows ... 

Carroll, M.T., Chang, C. and Bader, R.F.W. (1988) Prediction ofthe structures of hydrogen-bonded complexes using the Laplacian of the charge density, Mol. Phys., 63, 387 105. 

Infra-red, microwave, and X-ray photoelectron spectroscopy Infra-red and ultra-violet spectroscopy has been widely used for investigating the structure of intermolecularly hydrogen-bonded complexes in the solid state (Novak, 1974) and in solution (Zundel, 1976, 1978 Clements et al., 1971a,b,c Pawlak et al., 1984). By analysing the infra-red spectra of equimolar liquid mixtures of amines with formic or acetic acid, the relative importance of structures [10] and [11] was estimated (Lindemann and Zundel, 1977). It was proposed that [10] and [11] make equal contributions to the observed structure of the complex when the p -value of the carboxylic acid is approximately two units lower than that of the protonated amine. 

A ferris wheel assembly involving a 1 1 complex of 19 and metallated [18]crown-6 is found in the cationic supermolecule [La(H20)3([ 18]crown-6)] (19+2H) + [48]. The lanthanum ion is coordinated by one calixarene sulfonate group, the [18] crown-6 and three aquo ligands, and the metallated crown sits inside the calixarene cavity. A helical hydrogen bonded chain structure is formed between the cationic assembly, water and chloride ions. The ferris wheel structural motif is also found in Ce3+ complex which simultaneously contains a Russian Doll assembly [44]. 

Fig. 25 The hydrogen bonded chain structure in complex [ Mo3S4(H20)7Cl2 2Hg](5)Cl4.14H20 where [ Mo3S4(H20)7Cl2 2Hg]4+ clusters are sandwiched between host 5 molecules [102]... 

FIGURE 7. Crystal structure of the bidendate hydrogen-bonded complex of l,2,6-trimethyl-4-pyri-done and 1,8-biphenylenediol177... 

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