27 research outputs found
Photochemistry of binuclear platinum (II) and gold (I) complexes
published_or_final_versionChemistryMasterMaster of Philosoph
Dodecanuclear Hexagonal-Prismatic M<sub>12</sub>L<sub>18</sub> Coordination Cages by Subcomponent Self-assembly
Dodecanuclear
hexagonal-prismatic M<sub>12</sub>L<sub>18</sub> cages were prepared
by a subcomponent self-assembly process with commercially available
pyridinecarboxaldehyde, <i>m</i>-xylenediamine, and cadmiumÂ(II)
perchlorate or manganeseÂ(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>-Î- and <i>mer</i>-Î-configured
metal centers in a 1:1 ratio. The cage structure also has a large
cavity that contains five perchlorate anions
Dodecanuclear Hexagonal-Prismatic M<sub>12</sub>L<sub>18</sub> Coordination Cages by Subcomponent Self-assembly
Dodecanuclear
hexagonal-prismatic M<sub>12</sub>L<sub>18</sub> cages were prepared
by a subcomponent self-assembly process with commercially available
pyridinecarboxaldehyde, <i>m</i>-xylenediamine, and cadmiumÂ(II)
perchlorate or manganeseÂ(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>-Î- and <i>mer</i>-Î-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
Synthesis of a new chiral ligand, 6, 6?-dihydroxy-5, 5?-biquinoline (BIQOL) and its applications in the asymmetric addition of diethylzinc to aldehydes
Aerobic Oxidation of an Osmium(III) <i>N</i>âHydroxyguanidine 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 osmiumÂ(III) <i>N</i>-hydroxyguanidine complex, <i>mer</i>-[Os<sup>III</sup>{NHî»CÂ(NH<sub>2</sub>)Â(NHOH)}Â(<b>L</b>)Â(CN)<sub>3</sub>]<sup>â</sup> (<b>OsGOH</b>, <b>HL</b> = 2-(2-hydroxyphenyl)Âbenzoxazole), 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>-[OsÂ(NO)Â(<b>L</b>)Â(CN)<sub>3</sub>]<sup>â</sup> 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<sup>III</sup>(NHCONH<sub>2</sub>)Â(<b>L</b>)Â(CN)<sub>3</sub>]<sup>2â</sup> and free NO.
Mechanisms for this aerobic oxidation at different pH values are proposed
Catalytic and asymmetric cyclopropanation of alkenes catalysed by rhenium(i) bipyridine and terpyridine tricarbonyl complexes
Aerobic Oxidation of an Osmium(III) <i>N</i>âHydroxyguanidine 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 osmiumÂ(III) <i>N</i>-hydroxyguanidine complex, <i>mer</i>-[Os<sup>III</sup>{NHî»CÂ(NH<sub>2</sub>)Â(NHOH)}Â(<b>L</b>)Â(CN)<sub>3</sub>]<sup>â</sup> (<b>OsGOH</b>, <b>HL</b> = 2-(2-hydroxyphenyl)Âbenzoxazole), 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>-[OsÂ(NO)Â(<b>L</b>)Â(CN)<sub>3</sub>]<sup>â</sup> 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<sup>III</sup>(NHCONH<sub>2</sub>)Â(<b>L</b>)Â(CN)<sub>3</sub>]<sup>2â</sup> 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. âReasonableâ 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, âreasonableâ knowledge of HBV was lower in Korean (OR = 0.3, 95% CI: 0.1â0.5), Filipino (OR = 0.3, 95% CI: 0.2â0.6), South Asian (OR = 0.3, 95% CI: 0.2â0.4), and Southeast Asian (OR = 0.3, 95% CI: 0.1â0.6) 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