Zinc polysulfides as precursors to zinc sulfide and as group transfer reagents

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.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Verma, Atul Kumar

Contributors dc:contributor

• Rauchfuss, Thomas B.

• Chemistry, Inorganic
• Engineering, Materials Science

Statement dc:rights

• Copyright 1996 Verma, Atul Kumar

Language dc:language

eng

Identifier

9780591199529
AAI9712470
(UMI)AAI9712470

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/20157