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Digitale Medien

Host–guest-like thiamine–anion complexation in thiaminium bis(tetrafluoroborate) (2001)

Hu, Ning Hai ; Aoki, Katsuyuki ; Adeyemo, Adegboye O. ; [weitere]

Oxford [u.a.] : International Union of Crystallography (IUCr)

Acta crystallographica 57 (2001), S. 1064-1066

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ISSN: 1600-5759

Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001

Thema: Chemie und Pharmazie , Geologie und Paläontologie , Physik

Notizen: In the title compound, 3-[(4-amino-2-methyl-5-pyrimidin-1-io)methyl]-5-(2-hydroxyethyl)-4-methylthiazolium(2+) bis(tetrafluoroborate), C12H18N4OS2+·2BF4−, the divalent thiamine cation (in the F conformation) is associated with BF4− anions via two characteristic bridging interactions between the thiazolium and pyrimidinium rings, i.e. C—H...BF4−...pyrimidinium and N—H...BF4−...thiazolium interactions. Thiamine molecules are linked by N—H...O hydrogen bonds to form a helical chain structure.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1107/S0108270101009222

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Digitale Medien

Kinetic studies of a catalyzed metalloporphyrin formation (1984)

Adeyemo, Adegboye O. ; Krishnamurthy, M.

New York, NY : Wiley-Blackwell

International Journal of Chemical Kinetics 16 (1984), S. 1075-1083

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ISSN: 0538-8066

Schlagwort(e): Chemistry ; Physical Chemistry

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: Kinetics of the incorporation of mercury(II) ion in tetra (p-trimethylammoniumphenyl)porphine have been investigated in aqueous solution at 30.0°C and 0.2 M (NaNO3) ionic strength. The reaction was found to be first order each in mercury(II) and the porphyrin. The forward (formation) and the reverse (dissociation) rate constants were found to be 1.9 ± 0.2 × 103 M-1 s-1 and 7 ± 2 × 106 M-1 s-1, respectively. Kinetics of zinc(II) incorporation in tetra(p-trimethylammoniumphenyl)porphine catalyzed by mercury(II) were also investigated. This catalysis is explained in terms of steady-state formation of mono mercury(II) porphyrin followed by zinc(II) displacement of mercury(II) ion from the porphyrin. Such a mechanism also illustrates the importance of porphyrin core deformation to metal incorporation.

Zusätzliches Material: 5 Ill.