The compounds MS(7/2-SCNEt2)(i;2-S2CNEt2)2 ( = niobium or tantalum) have been prepared from the reaction of NaS2CNEt2 with M2Cl6(SC4H8)3. These new compounds were characterized using spectroscopic methods and X-ray crystallography. NbS(SCNEt2)(S2CNEt2)2•* 1 /4C6H6 crystallizes in the triclinic space group, PI, with cell parameters of a = 10.390 (4) k,b= 14.002 (3) A, c = 18.314 (11) A, a = 104.39 (4)°, ß = 93.13 (4)°, y = 90.11 (3)°, V = 2576 (2) A3, and Z = 4. The coordination sphere of the metal(V) atom consists of a lone sulfur atom, two chelating dithiocarbamate ligands, and one thiocarbamyl ligand bound through both the carbon and the sulfur atoms. The resulting structure is a seven-coordinate pentagonal bipyramid having the lone sulfur atom and a sulfur from one of the dithiocarbamate ligands occupying the polar positions. The formation of a sulfur ligand and thiocarbamyl ligand, SCNEt2~, corresponds to the oxidative addition of one C-S bond to the metal(III) center with concomitant cleavage of the dimer. A dimeric compound with bridging tridentate dithiocarbamate ligands is proposed as a necessary intermediate for the oxidative addition reaction to occur.
A desirable solvent replacement has been effected in the synthesis of persubstituted phosphonitriiic hydroquinone prepolymer materials. The replacement of carbon tetrachloride with cyclohexane has no adverse effect on the composition and quality of the material prepared. The overall yield of the reaction increases from 65 to 70% and the toxicity of the reaction mixture and of the waste generated from the reaction are greatly reduced. The particularly close match of solvent properties between carbon tetrachloride and cyclohexane makes this an excellent solvent replacement. Such changes to less-expensive, iess-toxic, and less-environmentally damaging solvents are on the increase. A brief list of some known replacement sofvents for use in polymer and coatings applications is presented. With a growing awareness of the health and environmental hazards of many common solvents, much time and effort has been expended in the search for suitable replacements. The budgetary impact of pertinent regulatory statutes has provided some of the driving force behind such efforts. This impact is felt by both industrial and educational laboratories. Consequently, industry and academia are formulating a number of useful replacement solvents and solvent mixtures. Proposed replacements are often judged on their ability to perform the pertinent function, yet they may have very different physical and chemical properties as compared to the solvent they are meant to replace. A search of the recent literature yields a number of replacements related to polymer and coatings applications: terpenes in place of halogenated solvents in cleaning applications,' toluene in place of carbon tetrachloride for preparing solutions of chlorosulfonated polyethyl-*
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.