Structure - Single-Crystal X-Ray Studies

A large number of single-crystal X-ray studies were carried out on mesogenic azo and azoxy compounds [3, 5, 121-131]. The general chemical structure of... 

HCl as in Eq. (107). The structures proposed for (XVI)-(XVIII) are shown below a single crystal X-ray study of (XVII) is in progress 192,192a). 

The relative stereochemistry of 386 <1999TL4391> and 387 <1998ACS107> and the structure of 388 <1997RCB1272> was revealed by single crystal X-ray studies. 

Ervafoline did not fragment under the acidic conditons used for the cleavage of other bisindole alkaloids. The complete structure and relative stereochemistry of ervafoline, as shown in formula 246, were determined by a single-crystal X-ray study. 

The first direct evidence for the structure of platinum-blues was provided by the single-crystal X-ray studies of cis-diammineplatinum a-pyridonate-blue, [Pt(2.25+)4(NH3)8(/x-a-pyridonato-N,0)4] (N03)5 H20 (48, 49). In the study, Barton and Lippard selected a-pyridone as a simplified model of pyrimidine bases (see Fig. 3), which must be the primary reason of their success in obtaining the first crystalline-blue material. 

Table 1. Crystallographic data are presented for the new phases which resulted from a 3d-metal substitution at the copper site in the n=l, 2 and 3 Bi-based cuprates. The periodicity of the structural modulation (p) is given by bold numbers when obtained from single crystal x-ray studies, otherwise the values were obtained from TEM studies. 

By X-ray diffraction, i.e. TlCl NM is isomorphous (powder pattern) to TiBr3 2NMe3 for which a trans trigonal bipyramidal structure was found via a single crystal X-ray study B. J. Russ and J. S. Wood, Chem. Common., 1966, 745. 

Single-crystal x-ray studies have shown that the borate ion in the potassium compound is identical to that found in borax (4) and has the structural... 

Single crystal X-ray studies on representative examples of the platinum bis(acetylides) were carried out to gain information on both the molecular geometry and nature of the packing of the acetylide moieties in the crystal. Selected crystal data for the various compounds are given in Table I. Full details of the structural analyses will be reported elsewhere. 

We thank the National Science Foundation, the donors of the Petroleum Research Fund administered by the American Chemical Society, and the Wrubel Computing Center for financial support. We are also indebted to Drs. John Huffman, Kirsten Folting, and William Streib at the Molecular Structure Center for single-crystal X-ray studies, to Mr. David L. Clark for assistance with the Fenske-Hall calculations, and to Drs. Dennis Lichtenberger and Edward Kober for obtaining photoelectron spectra. 

Also present are both four- and three-coordinate Al centers, the latter probably giving rise to high Lewis acidity. Structures of some aluminoxane clusters have also been determined in the solid state by single-crystal X-ray studies. One such structure, that of [Al706Me16] anion, is shown by 6.30. Another structure, 6.31, has been proposed on the basis of mass spectroscopic data. All the evidences taken together point to open-cage rather than dense mineral structures for the aluminoxanes in MAO solutions. 

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