Cyclophosphates as ligands for cobalt(III) in water.
Examination of cyclotriphosphate and cyclotetraphosphate as ligands for Co(III) in aqueous solutions revealed that cyclotetraphosphate affords stable complexes as a hemilabile ligand, while cyclotriphosphate exhibits facile hydrolysis.
Syntheses and studies of group 6 terminal pnictides, early-metal trimetaphosphate complexes, and a new bis-enamide ligand
Investigated herein is the reactivity of the terminal-nitrido, trisanilide tungsten complex, NW(N[iPr]Ar)3 (Ar = 3,5-Me 2C6H3, 1). Nitride 1 has been shown to undergo an "N for (O)C1 metathesis with a variety of acid chlorides to form oxochloride (Ar[i-Pr]N) 3W(O)C1 (2) and the corresponding nitriles. The reaction of 1 with acid chlorides has been shown to proceed through an acylimido chloride intermediate. Furthermore, oxochloride 2 has been converted to a terminal phosphido trisanilide tungsten complex, PW(N[i-Pr]Ar) 3 (9) by treatment with the anionic niobium phosphide complex [Na(OEt2)][PNb(N[Np]Ar) 31. Nitride 1 and oxochloride 2 have been converted to pseudo-octahedral complexes through the use of electrophilic reagents such as oxalyl chloride and phosphorus pentachloride. (Ar[iPr]N)3W(OCN)(Cl) 2 (10) and (Ar[i-Pr]N)3W(N=PCl 3)(Cl) 2 (11) are synthesized by treating compound 1 with oxalyl chloride and PCl5, respectively. Similarly, (Ar[i-Pr]N) 3W(Cl) 3 (12) is formed by treatment of oxochloride 2 with PC15 with concomitant loss of oxyphosphorus trichloride. Reaction studies of trichloride 12 undertaken in the attempt to generate a low-coordinate tungsten species are also presented. Also reported presently is a new procedure for synthesis of the terminal phosphoryl complex (Ar[t-Bu]N)3MoPO (17) by treating phosphide (Ar[t-Bu]N) 3MoP (16) with the potent oxygen atom transfer (OAT) reagent mesitylnitrile oxide (MesCNO). In conjunction with collaborators, the thermodynamic and kinetic aspects of MesCNO as an OAT reagent with phosphide 16 and phosphines have been investigated. Density Functional Theory calculations of OAT reactions of MesCNO are also shown. In an effort to further develop the coordination chemistry of the trianionic, tridentate ligand trimetaphosphate, studies are described whereupon trimetaphosphate is metallated with molybdenum. (MeCN)3Mo(CO) 3 reacts with [PPN] 3[P30 9] -H20 ([PPN] = [Ph3P=N-PPh3]') to form the trimetaphosphate salt [PPN] 3[(P30 9)Mo(CO) 3] ([PPN] 3[18]) in high yield. Efforts to generate trimetaphosphate vanadium oxo ((P30 9)V--O, 19) are also revealed. Finally, the synthesis of a new bis-enamide ligand class is described by the double addition of ketenimines to dilithium arylphosphanides. Formation of [Li(thf)]2 {PhP[C(CPh2)NPh] 21 ([Li(thf)] 2[20]) and [Li(thf)]2{MesP[C(CPh2)NPh] 2} ([Li(thf)]2[21]) are presented. The synthesis of tantalum species utilizing these new bis-enamide ligands is also demonstrated. Thesis Supervisor: Christopher C. Cummins Title: Professor of Chemistry
Essential Oil Profiles of 168 Perilla Cultivars by Head Space Solid Phase Micro-extraction Gas Chromatography Mass Spectrometry
Abstract In order to comprehensively elucidate the chemical biosynthesis in Perillla (commonly used in traditional herbal medicine), an untargeted analysis based on Gas chromatography-Mass spectrometry was done to reveal the metabolites from 168 different species of Perilla, with 73 components were identified. The results based on the 168 samples, which can be classified into five chemotypes, reveals that different genetic background have a significant influence on the metabolic synthesis of Perilla. The results of heat map for the components of different species and the principal component analysis are implying that the Perilla chemotypes are clustered for characteristic compounds. This study, which used optimized solid-phase microextraction conditions to investigate volatile oil composition, expanded our knowledge of metabolic pathways in Perilla. The differences between chemotypes provide a scientific basis for distinguishing between Perilla species, which not only can improve the testing standards for essential oils from Perilla herbs, but also can be beneficial to Perilla breeding.