Molybdenum (IV) imido silylamido and hydride complexes : stoichiometric and catalytic reactivity, mechanistic aspects of hydrosilation reactions

This thesis describes the synthesis, structural studies, and stoichiometric and catalytic reactivity of novel Mo(IV) imido silylamide (R'N)Mo(R2)(173_RIN-SiR32-H)(PMe3)n (1: Rl = tBu, Ar', Ar; R2 = Cl; R32 = Me2, MePh, MeCl, Ph2, HPh; n = 2; 2: R' = Ar, R2 = SiH2Ph, n = 1) and hydride complexes (ArN)Mo(H)(R)(PMe3)3 (R = Cl (3), SiH2Ph (4». Compounds of type 1 were generated from (R'N)Mo(PMe3)n(L) (5: R' = tBu, Ar', Ar; L = PMe3, r/- C2H4) and chlorohydrosilanes by the imido/silane coupling approach, recently discovered in our group. The mechanism of the reaction of 5 with HSiCh to give (ArN)MoClz(PMe3)3 (8) was studied by VT NMR, which revealed the intermediacy of (ArN)MCh(172 -ArN=SiHCl)(PMe3)z (9). The imido/silyl coupling methodology was transferred to the reactions of 5 with chlorine-free hydrosilanes. This approach allowed for the isolation of a novel ,B-agostic compound (ArN)Mo(SiHzPh)(173 -NAr-SiHPhH)(PMe3) (10). The latter was found to be active in a variety of hydrosilation processes, including the rare monoaddition of PhSiH3 to benzonitrile. Stoichiometric reactions of 11 with unsaturated compounds appear to proceed via the silanimine intermediate (ArN)M(17z-ArN=SiHPh)(PMe3) (12) and, in the case of olefins and nitriles, give products of Si-C coupling, such as (ArN)Mo(R)(173 -NAr-SiHPh-CH=CHR')(PMe3) (13: R = Et, R' = H; 14: R = H, R' = Ph) and (ArN)Mo(172-NAr-SiHPh-CHR=N)(PMe3) (15). Compound 13 was also subjected to catalysis showing much improved activity in the hydrosilation of carbonyls and alkenes. Hydride complexes 3 and 4 were prepared starting from (ArN)MoCh(PMe3)3 (8). Both hydride species catalyze a diversity of hydrosilation processes that proceed via initial substrate activation but not silane addition. The proposed mechanism is supported by stoichiometric reactions of 3 and 4, kinetic NMR studies, and DFf calculations for the hydrosilation of benzaldehyde and acetone mediated by 4.

Bee Communities in Restored Landfill Sites of Niagara Region

This study examined the impact of habitat restoration on bee communities (Hymenoptera: Apidae) of the Niagara Region, Ontario, Canada. Bee abundance and diversity was studied in three restored landfill sites: the Glenridge Quarry Naturalization Site (GQNS) in St. Catharines, Elm Street Naturalization Site in Port Colborne, and Station Road Naturalization Site in Wainfleet during 2011 and 2012. GQNS represented older sites restored from 2001-2003. Elm and Station sites represented newly restored landfills as of 2011. These sites were compared to control sites at Brock University where bee communities are well established and again to other landfills where no stable habitat was available before restoration. The objective of this study is to investigate the impact of restoration level on bee abundance and diversity in restored landfill sites of the Niagara Region. Based on the increased disturbance hypothesis (InDH) and the intermediate disturbance hypothesis (IDH), I hypothesized that bee abundance and diversity will follow two patterns. First pattern according to InDH suggest that as the disturbance decrease the bee abundance and diversity will increased. Second pattern according to the IDH bee abundance and diversity will be the highest at the intermediate level of disturbance. A total of 7 173 bees were collected using pan traps and flower collections, from May to October 2011 and 2012. Bees were classified to five families, 21 genera and sub-genera, containing at least 78 species. In 2011 bee abundance was not significantly different among restoration levels while in 2012 bee abundance was significant difference among restoration level. According to family there were no significant difference in Halictidae and Apidae abundance among restoration level while Colletidae and Megachilidae abundance were varied among restoration levels. The bee species richness was highest in the newly restored sites followed by restored control sites, and then the control site. The current study demonstrates that habitat restoration results in rapid increases in bee abundance and diversity for newly restored sites, and, further, that it takes only 2-3 years for bee assemblages in newly restored sites to arrive at the same levels of abundance and diversity as in nearby control sites where bee communities are well established.

Indenture between the Honourable William Dickson of Niagara and Robert Dickson of Niagara

Indenture between the Honourable William Dickson of Niagara and Robert Dickson of Niagara for 1,253 acres in the 11th and 12th Concession in Dumphries, This was recorded on Jan.22, 1848 in Folio 173, memorial 137, March 25, 1840.

La informática aplicada al diseño de un (EIS) sistema de información ejecutiva, como soporte principal en la toma de decisiones

Tesis (Maestría en Informática Administrativa) U.A.N.L.

Efectos de algunos detergentes sobre los protozoarios presentes en los lodos activados de una planta de tratamiento por María de Montserrat Zamora Mendoza

Tesis (Maestría en Ciencias con Especialidad en Ingeniería Ambiental) U.A.N.L.

Aspectos teórico-metodológicos de los procesos de formación docente universitaria

Tesis (Maestría en Enseñanza Superior) U.A.N.L.

La vinculación con el sector productivo y la educación tecnológica industrial [por] Gilberto A. G. Serna Chacón

Tesis (Maestría en Administración Pública) U.A.N.L.

México ante el Sistema Interamericano de Protección de los Derechos Fundamentales

Tesis (Maestro en Ciencias con Especialidad en Derecho Público) U.A.N.L.

Efecto de la meglumina de flunixín y la progesterona como auxiliares en el mantenimiento de la gestación en bovinos por Luis Ricardo Pérez García

Tesis (Maestría en Ciencias con Especialidad en Producción Animal) U.A.N.L.

Texto de apoyo para la materia [de] sistemas de información III de la licenciatura en ciencias computacionales de la Facultad de Ciencias Físico-Matemáticas de la Universidad Autónoma de Nuevo León

Tesis (Maestro en Ciencias de la Administración con Especialidad en Relaciones Industriales) - UANL, 2001

Los narradores y protagonistas de Sandra Cisneros en Woman Hollering Creek and Other Stories

Tesis ( Maestría en Letras Españolas ) U.A.N.L.

La suspensión del procedimiento penal a prueba del acusado

[Tesis] (Maestro en Ciencias Penales) U.A.N.L.

El fortalecimiento de los valores en el estudiante en la materia de Español III, módulo V, del nivel medio superior

[Tesis] ( Maestría en Enseñanza Superior) U.A.N.L.

Guía didáctica para la asignatura de Construcción V, proyecto ejecutivo 1, en la Facultad de Arquitectura de la Universidad Autónoma de Nuevo León

[Tesis] ( Maestría en Educación Superior) U.A.N.L.

Tratamiento de un efluente salino proveniente de una papelera, mediante un sistema de evaporación de triple efecto

1Tesis] ( Maestría en Ciencias con Especialidad en Ingeniería Ambiental) U.A.N.L.