pH-independent decomposition reactions of L-ascorbic acid in aqueous metal solutions .1. Formation and structures of Co-II and Gd-III oxalates

UNALEROGLU C., ZUMREOGLU KARAN B., ZENCIR Y., Hokelek T.

POLYHEDRON, cilt.16, sa.13, ss.2155-2161, 1997 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 16 Sayı: 13
  • Basım Tarihi: 1997
  • Doi Numarası: 10.1016/s0277-5387(96)00563-3
  • Dergi Adı: POLYHEDRON
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.2155-2161
  • Anahtar Kelimeler: L-ascorbic acid, metal-ascorbate complexes, cobalt oxalate, gadolinium oxalate, VITAMIN-C, COORDINATION CHEMISTRY, COMPLEXES, CHROMIUM(VI), OXIDATION, IONS
  • Hacettepe Üniversitesi Adresli: Evet

Özet

The reactions of L-ascorbic acid in aqueous Cd-II and Gd-III solutions were investigated at pH values of 2, 6 and 12. IR spectral studies revealed that the initially formed metal-ascorbates slowly decompose to the solid oxalate complexes in a pH-independent manner. The compositions of the cobalt oxalates were defined as CoC2O4 . 2H(2)O and those of Gd-III showed variations due to the stereochemical changes in the precursor ascorbate complexes related to pH. X-ray crystal analyses were performed and the structure of Gd-2(C2O4)(3) . 6H(2)O is reported for the first time. (C) 1997 Elsevier Science Ltd.