A systematic study of the liquid-crystalline properties of 30 metal bis (/3-diketonate) complexes (M = Cu, VO, Pd) that exhibit discotic mesophases is reported. This study has determined that the ability of the metal center to influence the mesophase stability depends upon the density of side chains. In the 10-side-chain complexes series 3, all of the materials were found to be liquid crystalline. In this series the M = VO analogues were found to have lower melting and clearing points than those with M = Cu and M = Pd. For the 12side-chain series 4 the opposite is true, and the M = VO materials have substantially higher clearing points. The differences between series 3 and 4 arise from the enhanced core-core interactions that accompany the increased side-chain density. The side-chain-induced organization assists the expression of the metal center's character in determining the stability and nature of the mesophase. The fact that the transition temperatures of the M = Cu and M = Pd compounds differ more in series 4 than in series 3 is also a manifestation of this greater organization. The influence of the metal centers is discussed in the context of intermolecular dative associations and for some phases of the M = VO materials these interactions produce polymeric (-V=0-V=0-)" structures.

LVAS, a congenital disease, is characterized by fluctuating sensorineural HL. Most hearing at PTA remained stable at least in one ear chronologically. The standard deviation of hearing at 500 Hz was the only prognostic factor for the progression of PTA. An enlarged vestibular aqueduct affects fluctuations of hearing, but the pathogenesis of HL still remains unclear and deserves further investigations.

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In our experience, primary sinonasal mucosa melanoma is prone to spread from the site of origin. The major obstacle in improving overall survival is achieving systemic control.

A comprehensive study of the liquid-crystalline properties of 51 bimetallic compounds based upon 1,3,5-triketonate and 1,3,5,7-tetraketonate ligands is reported. These materials are liquid crystalline when six or more side chains are appended to the mesogenic core, and only columnar phases were observed. Most of the liquid crystals were homonuclear dicopper complexes. Schiff-base derivatives of some of the triketones allowed for the synthesis of heteronuclear bimetallic liquid crystals. The NiCu and NiPd Schiff-base complexes are the first heteronuclear liquid crystals with proximate (strongly interacting) metal centers. Other heteronuclear complexes investigated were not liquid crystalline due to the tendency to retain coordinated solvent or to form strongly associated structures in the absence of axial ligands. The use of complementary shapes was demonstrated as a means to generate average relative organizations (correlations) between the complexes. The presence of these correlated structures was shown through comparisons of the structures, phase behavior, and the immiscibility between materials having the same phase but different shapes. Correlated structures were shown which produce average rotations of 90°and 180°between nearestneighbor molecules. A crystal structure of one compound confirmed that a similar superstructure was exhibited in the solid state. In addition, it was found that the correlated structures exhibit relatively short (3.29 A) correlations between the mesogens, thereby allowing for strong intermolecular interactions. The ability to control the orientation and relative position of transition metal centers in liquid crystals has applications in the design of new liquid-crystalline materials with useful magnetic and electronic properties.