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Rauchfuss, Thomas B. Verma, Atul Kumar 2011-05-07T12:30:38Z 2011-05-07T12:30:38Z 10000-01-01 1996 In the first part of the thesis, reactions of zinc powder with solutions of elemental sulfur in various donor solvents are described. Complexes of the type $\rm ZnS\sb6$(N-donor)$\sb2$ are obtained for the ligands tetramethylethylenediamine (TMEDA), N-methylimidazole (MeIm), and 4-(N,N-dimethylamino)pyridine (DMAP). Ligand competition studies on pyridine solutions revealed that the relative stability constants $\rm (DMAP>MeIm>TMEDA>pyridine)$ parallels the basicity of the ligands. Crystallographic analysis shows that $\rm ZnS\sb6$(TMEDA) adopts a tetrahedral geometry with a seven-membered $\rm ZnS\sb6$ ring. Solutions of $\rm ZnS\sb6$(TMEDA) undergo ligand exchange with other ligands L to afford $\rm ZnS\sb6L\sb2$ (L = MeIm, quinuclidine). The pyridine analog, $\rm ZnS\sb6py\sb2$ also undergoes ligand substitution with TEEDA $(N,N,N\prime,N\prime$-tetraethylethylenediamine) and ($-$)-sparteine to afford $\rm ZnS\sb6$(TEEDA) and $\rm ZnS\sb6\{(-)$-sparteine$\};$ these complexes can not be prepared by the reaction of sulfur and zinc dust in TEEDA or ($-$)-sparteine. Optical and reactivity studies showed that MeIm, but not pyridine, displaces the polysulfide from $\rm ZnS\sb6(MeIm)\sb2$ as indicated by the appearance of the chromophore $\rm S\sb3\sp-.$ ZnS$\sb6$(TMEDA) reacts with the electrophilic acetylenes methylpropiolate and dimethylacetylenedicarboxylate (DMAD) to give the dithiolene complexes $\rm ZnS\sb2C\sb2R(CO\sb2Me)$(TMEDA), where R = $\rm CO\sb2Me,$ H. The second portion of thesis studies the conversion of $\rm ZnS\sb6$(N-donor)$\sb2$ complexes into ZnS and related materials. Solid $\rm ZnS\sb6(TMEDA)$ cleanly decomposes at $350\sp\circ$C to cubic ZnS, as indicated by TGA and preparative scale studies. Submicron cubic ZnS is generated upon partial desulfurization of $\rm ZnS\sb6(TMEDA)$ with tertiary phosphines as established by electron microscopic studies. The reaction of $\rm ZnS\sb6(MeIm)\sb2$ with 5 equiv of zinc dust affords nanosize insoluble material $\rm ZnS(MeIm)\sb{1\sim x}\ (x\approx 0{-}0.3).$ This unusual species, unlike cubic ZnS, is very reactive towards MeIm solutions of sulfur and affords $\rm ZnS\sb6(MeIm)\sb2.$ The TGA, XPS, CL, and SS MAS $\sp{13}$C NMR spectroscopic measurements suggest a strong Zn-MeIm interaction in $\rm ZnS(MeIm)\sb{1\sim x}.$ This species also reacts with $\rm Cu\sb4S\sb{10}(MeIm)\sb4$ to afford $\rm\lbrack Zn(MeIm)\sb6\rbrack\lbrack Cu\sb4S\sb{12}\rbrack.$ In the final Chapter, the species $\rm ZnS\sb6(TMEDA)$ has been developed as a potent polysulfido-transfer reagent. The reaction of this zinc reagent with $\rm Cp\sb2TiCl\sb2$ gives $\rm Cp\sb2TiS\sb5.$ When a $\rm CS\sb2$ slurry of $\rm ZnS\sb6(TMEDA)$ is treated with $\rm Se\sb2Cl\sb2,$ chalcogenospecific formation of 1,2-$\rm Se\sb2S\sb6$ is observed, as confirmed by reverse phase HPLC, Raman, and $\sp{77}$Se NMR spectroscopic measurements. A $\rm CS\sb2$ solution of 1,2-$\rm Se\sb2S\sb6$ is mildly reactive towards UV-photolysis, rearranging to its 1,3-, 1,4-, 1,5-, and other isomers over the course of several hours. The reaction of $\rm CH\sb2Cl\sb2$ solutions of $\rm ZnS\sb6(TMEDA)$ with $\rm TiCl\sb4$ affords a brown solid $\rm TiS\sb{x}.$ Extraction of $\rm TiS\sb{x}$ with MeIm, affords an air-sensitive molecular complex $\rm Ti(S\sb2)\sb2(MeIm)\sb3.$ The crystal structure reveals a pseudo trigonal-bipyramidal geometry around Ti, with the two MeIm ligands bound axially. The oxidation of $\rm TiS\sb4(MeIm)\sb3$ generates a dinuclear $\mu$-oxo species $\rm\lbrack Ti\sb2(S\sb2)\sb2(\mu$-$\rm S\sb2)(\mu$-O)$\rm (MeIm)\sb4\rbrack ,$ as confirmed by single crystal X-ray crystallography. Made available in DSpace on 2011-05-07T12:30:38Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9712470.pdf: 6252156 bytes, checksum: 742dea4ec25b06a99ff1784d1df2ed06 (MD5) Previous issue date: 1996 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:41:57Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:18:13-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission U of I Only 9780591199529 AAI9712470 (UMI)AAI9712470 http://hdl.handle.net/2142/20157 eng Copyright 1996 Verma, Atul Kumar Chemistry, Inorganic Engineering, Materials Science Zinc polysulfides as precursors to zinc sulfide and as group transfer reagents text Chemistry Chemistry University of Illinois at Urbana-Champaign Dissertation Ph.D.