Thiocarbonyl, thiocarbyne and thiocarbene complexes of tungsten

This dissertation describes the synthesis and reactions of tungsten thiocarbonyl, thiocarbyne and thiocarbene complexes. Treatment of Bu[subscript]4N (HB(pz)[subscript]3) (CO)[subscript]2W(CS) (HB(pz)[subscript]3[superscript]- is the tris (1-pyrazolyl)borato ligand) with (([eta][superscript]5-C[subscript]9H[subscript]7)Mo(CO)[subscript]2(MeCN)[subscript]2) BF[subscript]4 gives the neutral W-Mo bonded dimer (HB(pz)[subscript]3) (CO)[subscript]2W([mu]-CS)Mo([eta][superscript]5-C[subscript]9H[subscript]7)(CO)[subscript]2. A single-crystal X-ray diffraction study shows that the molybdenum atom achieves an 18-electron configuration by accepting [pi]-electron density from the thiocarbonyl ligand which is also bonded via the carbon to the tungsten. This is the first example of a complex containing a four-electron donating, side-on bridging thiocarbonyl ligand. The thiocarbonyl complex (HC(pz)[subscript]3) (CO)[subscript]2W(CS) is prepared by the reaction of trans-IW(CO)[subscript]4(CS)[superscript]- with HC(pz)[subscript]3. The nucleophilic sulfur atom of the CS ligand can be methylated with Me[subscript]3O[superscript]+ to give the thiocarbyne (HC(pz)[subscript]3) (CO)[subscript]2W≡C-SMe[superscript]+. Reaction of the carbyne with phosphorus nucleophiles (PR[subscript]3) gives the [eta][superscript]2-ketenyl derivatives (HC(pz)[subscript]3) (CO) (R[subscript]3P)[overline]W[C(O)CSMe][superscript]+. Protonation of the carbyne with HBF[subscript]4· Et[subscript]2O produces the [eta][superscript]2-carbene (HC(pz)[subscript]3] (CO)[subscript]2[overline]W[[eta][superscript]2-CH(SMe)] [superscript]2+, which reacts with PR[subscript]3, RS[superscript]- and H[superscript]- nucleophiles to give the carbene adducts (HC(pz)[subscript]3] (CO)[subscript]2[overline]W[[eta][superscript]2-CH(L)(SMe)][superscript] n+. The SMe[superscript]+ electrophile adds to the carbyne carbon of (HB(pz)[subscript]3) (CO)[subscript]2W≡C-SMe, to give (HB(pz)[subscript]3] (CO)[subscript]2[overline]W[[eta][superscript]2-C(SMe)SMe][superscript]+, containing an [eta][superscript]2-dithiocarbene ligand bonded to the metal through both the carbon and one of the sulfur atoms. Reactions of the dithiocarbene complex with nucleophiles (Nuc) give the air stable adducts (HB(pz)[subscript]3] (CO)[subscript]2[overline]W[[eta][superscript]2-C(SMe)(Nuc)SMe] (Nuc = SR, H, CH[subscript]3 and PMe[subscript]3). Heating the MeS[superscript]- dithiocarbene adduct (HB(pz)[subscript]3] (CO)[subscript]2[overline]W[[eta][superscript]2-C(SMe)[subscript]2SMe] above 60 °C results in the loss of CO and C-S bond cleavage, giving the carbyne (HB(pz)[subscript]3) (MeS)[subscript]2W≡C-SMe, which was characterized by X-ray analysis. Thermal and photolytic reactions of the other dithiocarbene adducts also give products resulting from C-S bond cleavage

Internet motives of users in the United States, United Kingdom, Australia, and Korea: a cross-cultural replication of the WMI

No Full Tex

MS 226 Guide to the Ruth SoRelle Papers (1950s-2019)

The collection includes photos, plaques, framed objects, clipping books, clipping files, reference and topic files, childhood writings, science and medical articles, reporter notebooks, and clippings from SoRelle\u27s budding career as a journalist at the University of Texas. One notable area of interest are the articles related to the HIV/AIDS epidemic in Houston. See more at MS 226

An experimental study of low pressure parallel plate radio frequency discharges

Radio frequency generated plasmas are used extensively in commercial manufacturing systems for a range of different applications including reactive ion etching, thin film deposition and surface modification. To optimise such processes a thorough understanding of the physical processes within the plasma is essential. In this thesis low pressure radio frequency argon plasmas are investigated in order to understand further the physics of their behaviour under certain conditions. Tuned Langmuir probes and microwave mterferometry are used as diagnostics methods to measure different plasma parameters as a function of gas pressure, current density and applied voltage. The spatial variations of these parameters are examined within the bulk plasma. In particular the electron distribution function was obtained from the Langmuir probe to observe transitions between heating modes which occur under certain conditions of the plasma. To further understand this transition a small variable transverse magnetic field was applied to the plasma to confine the electrons and modify their trajectories Mathematical models devised and compared to the experimental results showed an excellent agreement. Finally the tuned probe was installed on other research systems in Ireland and abroad to characterise the plasma produced by different gases, with other methods of power coupling and in various chamber geometries

Homeotic genes controlling flower development in Antirrhinum

In order to study genes controlling flower development, we have carried out an extensive transposon-mutagenesis experiment in Antirrhinum majus. More than 15 independent homeotic mutations were obtained, allowing three categories of genes to be defined. The first includes floricaula (flo), a primary gene required for the initiation of the floral developmental pathway. In the absence of the wild-type flo product, proliferating inflorescence meristems arise in place of flowers. The flo gene has been isolated and shown to be expressed transiently in a subset of organ primordia in the floral meristem. The second category includes genes that affect the identity, and also sometimes the number, of whorls of organs in the flower. These genes act in overlapping domains so that each whorl has a distinct combination of gene functions, suggesting a model for the genetic control of whorl identity and number. Genes of the third category control differences between organs in the same whorl and hence the overall symmetry of the flower. We discuss how the basic plan of the flower and inflorescence may arise through the interactions between the three categories of genes

Immunoproteomic Analysis of Proteins Expressed by Two Related Pathogens, Burkholderia multivorans and Burkholderia cenocepacia, during Human Infection.

Burkholderia cepacia complex (Bcc) is an opportunistic bacterial pathogen that causes chronic infections in people with cystic fibrosis (CF). It is a highly antibiotic resistant organism and Bcc infections are rarely cleared from patients, once they are colonized. The two most clinically relevant species within Bcc are Burkholderia cenocepacia and Burkholderia multivorans. The virulence of these pathogens has not been fully elucidated and the virulence proteins expressed during human infection have not been identified to date. Furthermore, given its antibiotic resistance, prevention of infection with a prophylactic vaccine may represent a better alternative than eradication of an existing infection. We have compared the immunoproteome of two strains each from these two species of Bcc, with the aim of identifying immunogenic proteins which are common to both species. Fourteen immunoreactive proteins were exclusive to both B. cenocepacia strains, while 15 were exclusive to B. multivorans. A total of 15 proteins were immunogenic across both species. DNA-directed RNA polymerase, GroEL, 38kDa porin and elongation factor-Tu were immunoreactive proteins expressed by all four strains examined. Many proteins which were immunoreactive in both species, warrant further investigations in order to aid in the elucidation of the mechanisms of pathogenesis of this difficult organism. In addition, identification of some of these could also allow the development of protective vaccines which may prevent colonisatio

The Grizzly, May 5, 1999

Spring Fling Success • Students Compete in First-Ever Ursinus Drag Competition • Student Speakers Selected • Commencement Program Announced • Mr. Ursinus: Anthony Petrino • Graduation Events Slated: Five Honorary Degrees to be Delivered at Graduation; Baccalaureate Speaker Announced • Let\u27s Throw Some Shoes! • Final Exam Schedule • Ursinus Lacrosse, Baseball Take Centennial Conference by Storm • UC Baseball Dominated the Centennial Conference Behind Great Pitching Performances by Wiatrak and Goldwater • Softball Falls Short of Top Shot • Newmaster Wins Pitcher of the Year • Adegunwa, O\u27Hara Dominate at CC Champs • Best Wishes to Spring Sports Seniorshttps://digitalcommons.ursinus.edu/grizzlynews/1443/thumbnail.jp