Photochemistry of binuclear platinum (II) and gold (I) complexes

published_or_final_versionChemistryMasterMaster of Philosoph

Dodecanuclear Hexagonal-Prismatic M₁₂L₁₈ Coordination Cages by Subcomponent Self-assembly

Dodecanuclear hexagonal-prismatic M₁₂L₁₈ cages were prepared by a subcomponent self-assembly process with commercially available pyridinecarboxaldehyde, <i>m</i>-xylenediamine, and cadmium­(II) perchlorate or manganese­(II) perchlorate. The NMR spectrum of the Cd cage shows that there are three independent ligand sets, and the X-ray crystal structure of the Mn cage reveals that the structure has both <i>fac</i>-Δ- and <i>mer</i>-Λ-configured metal centers in a 1:1 ratio. The cage structure also has a large cavity that contains five perchlorate anions

Dodecanuclear Hexagonal-Prismatic M₁₂L₁₈ Coordination Cages by Subcomponent Self-assembly

Dodecanuclear hexagonal-prismatic M₁₂L₁₈ cages were prepared by a subcomponent self-assembly process with commercially available pyridinecarboxaldehyde, <i>m</i>-xylenediamine, and cadmium­(II) perchlorate or manganese­(II) perchlorate. The NMR spectrum of the Cd cage shows that there are three independent ligand sets, and the X-ray crystal structure of the Mn cage reveals that the structure has both <i>fac</i>-Δ- and <i>mer</i>-Λ-configured metal centers in a 1:1 ratio. The cage structure also has a large cavity that contains five perchlorate anions

New chiral bidentate ligands containing thiazolyl and pyridyl donors for copper-catalyzed asymmetric allylic oxidation of cyclohexene

Chiral bidentate ligands 1-3, which contain a combination of thiazolyl and pyridyl donors units, were prepared. The syntheses are facile and being based on Krohnke condensation of a pinene derivative to form the pyridine ring. Modification at the 8-position of the tetrahydroquinoline ring can be carried out by alkylation reaction with 2a and 3a but not 1a. The structure of a copper(II) perchlorate complex of 1a was characterized with X-ray crystallography, which reveals the binding of the pyridyl-thiazole as a N-N donors at the copper center. The copper(I) thiazolyl-pyridine complexes prepared in situ are active catalysts in the enantioselective allylic oxidation of cyclohexene using tert-butyl perbenzoate as the oxidant. The isolated yields of the allylic benzoate were up to 98\%, and enantioselectivity was up to 62\% e.e. (c) 2005 Elsevier B.V. All rights reserved

Aerobic Oxidation of an Osmium(III) <i>N</i>‑Hydroxyguanidine Complex To Give Nitric Oxide

The aerobic oxidation of the <i>N</i>-hydroxyguanidinum moiety of <i>N</i>-hydroxyarginine to NO is a key step in the biosynthesis of NO by the enzyme nitric oxide synthase (NOS). So far, there is no chemical system that can efficiently carry out similar aerobic oxidation to give NO. We report here the synthesis and X-ray crystal structure of an osmium­(III) <i>N</i>-hydroxyguanidine complex, <i>mer</i>-[Os^III{NHC­(NH₂)­(NHOH)}­(<b>L</b>)­(CN)₃]⁻ (<b>OsGOH</b>, <b>HL</b> = 2-(2-hydroxyphenyl)­benzoxazole), which to the best of our knowledge is the first example of a transition metal <i>N</i>-hydroxyguanidine complex. More significantly, this complex readily undergoes aerobic oxidation at ambient conditions to generate NO. The oxidation is pH-dependent; at pH 6.8, <i>fac</i>-[Os­(NO)­(<b>L</b>)­(CN)₃]⁻ is formed in which the NO produced is bound to the osmium center. On the other hand, at pH 12, aerobic oxidation of <b>OsGOH</b> results in the formation of the ureato complex [Os^III(NHCONH₂)­(<b>L</b>)­(CN)₃]^2– and free NO. Mechanisms for this aerobic oxidation at different pH values are proposed

Aerobic Oxidation of an Osmium(III) <i>N</i>‑Hydroxyguanidine Complex To Give Nitric Oxide

The aerobic oxidation of the <i>N</i>-hydroxyguanidinum moiety of <i>N</i>-hydroxyarginine to NO is a key step in the biosynthesis of NO by the enzyme nitric oxide synthase (NOS). So far, there is no chemical system that can efficiently carry out similar aerobic oxidation to give NO. We report here the synthesis and X-ray crystal structure of an osmium­(III) <i>N</i>-hydroxyguanidine complex, <i>mer</i>-[Os^III{NHC­(NH₂)­(NHOH)}­(<b>L</b>)­(CN)₃]⁻ (<b>OsGOH</b>, <b>HL</b> = 2-(2-hydroxyphenyl)­benzoxazole), which to the best of our knowledge is the first example of a transition metal <i>N</i>-hydroxyguanidine complex. More significantly, this complex readily undergoes aerobic oxidation at ambient conditions to generate NO. The oxidation is pH-dependent; at pH 6.8, <i>fac</i>-[Os­(NO)­(<b>L</b>)­(CN)₃]⁻ is formed in which the NO produced is bound to the osmium center. On the other hand, at pH 12, aerobic oxidation of <b>OsGOH</b> results in the formation of the ureato complex [Os^III(NHCONH₂)­(<b>L</b>)­(CN)₃]^2– and free NO. Mechanisms for this aerobic oxidation at different pH values are proposed

Hepatitis B Awareness and Knowledge in Asian Communities in British Columbia

Background. Our study examined hepatitis B virus (HBV) awareness and knowledge in Asian communities in British Columbia (BC). Methods. A statistical random sample representation of Chinese, Korean, Filipino, South Asian, and Southeast Asian populations in Greater Vancouver was surveyed by telephone. Multiple logistic regression analysis was performed to identify predictors of HBV knowledge. Results. General awareness of HBV was reported in 78.8% (798/1013). HBV awareness was the highest in Chinese (89%) and Filipino (88%) populations and the lowest in the South Asian (56%) population. “Reasonable” knowledge of HBV was elicited in 76.8% (778/1013). Higher HBV knowledge was associated with younger age (p=0.014), higher education (p<0.0001), Chinese ethnicity (p<0.0001), and use of media (p=0.01) and Internet (p=0.024) for health information. Compared to the Chinese (OR = 1.0) population, “reasonable” knowledge of HBV was lower in Korean (OR = 0.3, 95% CI: 0.1–0.5), Filipino (OR = 0.3, 95% CI: 0.2–0.6), South Asian (OR = 0.3, 95% CI: 0.2–0.4), and Southeast Asian (OR = 0.3, 95% CI: 0.1–0.6) populations. 54.8% (555/1013) felt that HBV education was inadequate and 80.1% (811/1013) preferred HBV education in their native languages. Conclusion. Compared to the Chinese population, other Asian communities in BC have lower HBV awareness and knowledge. Public education should target older and less educated and Korean, Filipino, South Asian, and Southeast Asian populations in their native languages via media and Internet