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Contributions to the Chemistry of Halogenosilane Adducts, 21. — Preparation, Properties, Crystal and Molecular Structure of Dichloro(1,10‐phenanthroline)bis(trichlorosilyl)silicon, (SiCl3)2SiCl2 · phen Si3Cl8 · phen (1) is obtained as a stable solid by the reaction of Si3Cl8 with phen. The structure of 1 in solution and its reactions correspond to that of Si3Cl8 · bipy reported earlier (1H‐NMR and IR studies). Rearrangement of 1 occurs in solution to give bis(silyl)‐substituted 1,2‐dihydrophenanthroline. From THF/C6H6 solution crystalline Si3Cl8 · phen · C6H6 (1a) is obtained. The X‐ray structure determination shows 1a to be monoclinic, space group P21/n (Z = 4). Phenanthroline is coordinated to the central silicon atom of the trisilane with its plane normal to the linear Si3 chain having two tetrahedral terminal SiCl3 groups. The coordination octahedron is regular.

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Bivalves, oysters, mussels, and clams are important constituents of riverine and estuarine ecosystems. Their shells and soft tissues provide information on the environments in which they live. Since they are filter feeders, they also are factors in improving water quality through removal of particulate matter from the water column. Finally, they are a valuable food source that has substantial economic value. Hence, characterization of shells and soft tissues is useful for improved understanding of these factors. Here, we used X-ray microprobes and computed microtomography facilities at the Brookhaven National Synchrotron Light Source to investigate elemental distributions in bivalves taken from locations around New York, Washington, DC, and New Orleans, LA. The results form the initial basis for compilation of a database of relevant parameters that can serve for tracking environmental changes and for assessing toxicity of particular metals. The work was enabled by active collaboration with students from the several regions, community groups, and research scientists. The collaboration was facilitated through use of web conferencing between Brookhaven National Laboratory and the varied locations.

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Monooxovanadium(V)complexes of the composition VOCl 3Àn (L) n (where L ¼ 2-phenylphenoxide ion; n ¼ 1-3) (1-3) have been synthesized in quantitative yields by the reaction of VOCl 3 with 2-phenylphenol in toluene. The characterization of the complexes has been accomplished by elemental analysis, molar conductance measurements, IR, 1 H-NMR, electronic, mass spectral, and thermal studies. The ligands as well as the complexes have been screened for their in vitro antimicrobial activity against the pathogenic bacteria Escherichia coli and Staphylococcus aureus and fungi Candida albicans, Aspergillus niger, and Fusarium oxysporum by a twofold serial dilution. An increase in the biocidal activity was observed for the vanadium complexes. The minimum inhibitory concentration (MIC) values were 6.25-25 mg mL À1 for complexes, relative to that of the free ligand of 25-50 mg mL À1 .

The octahedral Si complexes CHC12SiC13. bipy (l), bipy (2), and C13SiCC12SiC13. bipy (3) are obtained by the reaction of the respective trichlorosilanes and 2,2'-bipyridine (bipy). Their composition is independent of the initial ratio of the components. X-ray structure determinations show the Si atoms of all three complexes to be octahedrally coordinated with the substituted methyl groups in axial positions. The configurations represent structures of least steric hindrance assuming spheric substituents and demonstrate the usefulness of this structural model for solid compounds (in contrast possibly to dissolved compounds) even for substituents deviating strongly from this assumption. Bond lengths and angles agree with the presence of hexaroordinated complexes. Deviations from expected values are interpreted in terms of considerable steric interactions. 3 represents a case of strongly hindered coordination requiring interesting steric adjustments.Strukturuntersuchungen an oktaedrischen 1 : 1-Komplexen von Halogensilanen und 2,2'-Bipyridin (bipy) und 1,lOPhenanthrolin (phen) haben gezeigt, daB die Konfiguration der Komplexe durch die sterischen Erfordernisse bestimmt ~i r d * -~) .Die Substituenten mit dem groljten Platzbedarf besetzen die axialen Positionen senkrecht zur Ebene des zweiziihligen Liganden (bipy, phen), in denen sie den weitesten Abstand voneinander haben; die kleineren Substituenten besetzen die sterisch ungunstigeren cis-standigen Positionen in der Ligandebene, in denen neben dem geringeren cis-Abstand zusatzlich starke sterische Wechselwirkungen mit den Wasserstoffatomen der den koordinierenden Stickstoffatomen benachbarten CH-Gruppen vorliegen 1: R = CHCI, 2: R = CCI, Darstellung der Komplexe und Vergleich ihrer Strukturen im gelosten und festen ZustandUntersuchungen, uber die an anderer Stelle berichtet wird6), haben gezeigt, daB durch Reaktion von substituierten Trichlorsilanen RSiC13 (R = CH,Cl, CHC12, CC13, CH,Si-C13, CC12SiC13, 0SiCl3) mit bipy und phen in THF, C6H,