Complexes of Zn2+, Cd2+, and Hg2+ with 2-(alpha-hydroxybenzyl)thiamine monophosphate chloride
Φόρτωση...
Ημερομηνία
Συγγραφείς
Dodi, K.
Gerothanassis, I. P.
Hadjiliadis, N.
Schreiber, A.
Bau, R.
Butler, I. S.
Barrie, P. J.
Τίτλος Εφημερίδας
Περιοδικό ISSN
Τίτλος τόμου
Εκδότης
American Chemical Society
Περίληψη
Τύπος
Είδος δημοσίευσης σε συνέδριο
Είδος περιοδικού
peer reviewed
Είδος εκπαιδευτικού υλικού
Όνομα συνεδρίου
Όνομα περιοδικού
Inorg Chem
Όνομα βιβλίου
Σειρά βιβλίου
Έκδοση βιβλίου
Συμπληρωματικός/δευτερεύων τίτλος
Περιγραφή
The binding sites of Zn2+, Cd2+, and Hg2+ in complexes with 2-(alpha-hydroxybenzyl)thiamine monophosphate chloride, (LH)Cl-+(-), have been investigated in the solid state [2-(alpha-hydroxybenzyl)thiamin monophosphate chloride monoprotonated at the phosphate group and protonated at N-1' is denoted as (LH)Cl-+(-); therefore, the ligand monoprotonated at the phosphate group and deprotonated at N-1' is L]. Complexes of formulae MLCl(2), M(LH)Cl-3, and (MCl(4))(2-)(LH)(2)(+) (M = Zn2+, Cd2+, and Hg2+) were isolated in aqueous and methanolic solutions, depending on pH. The crystal structure of the complex of formula HgL(2)Cl(2) was solved, together with that of the free ligand (LH)Cl-+(-), by X-ray crystallography. HgL(2)Cl(2) crystallizes in C2/c, with a = 32.968(6) Angstrom, b = 7.477(2) Angstrom, c = 21.471(4) Angstrom, beta = 118.19(1)degrees, V = 4665(2) Angstrom(3), and Z = 4. (LH)Cl-+(-) crystallizes in Cc, with a = 10.951(3) Angstrom, b = 17.579(4) Angstrom, c = 13.373(3) Angstrom, beta = 105.36(2)degrees, V = 2482.4(10) Angstrom(3), and Z = 4. Mercury(II) binds to the N(1') of the pyrimidine ring. Both ligands are in the S conformation [Phi(T) = -98.1(9)degrees and Phi(P) = 176.1(10)degrees for HgL(2)Cl(2) and Phi(T) = 104.1(5)degrees and Phi(P) = 171.9(6)degrees for (LH)Cl-+(-)]. P-31 and C-13 NMR spectra, together with vibrational spectra (IR/Raman), are used to deduce the binding sites of the metal and the protonation states of the ligand at various pH values. It is found that solid-state P-31 NMR spectroscopy is particularly useful in characterizing these complexes as the P-31 shielding tensors are sensitive to the state of the phosphate group. On the other hand, the P-31 NMR spectra indicate that direct bonding between Zn2+ and Cd2+ to the phosphate can occur under certain preparation conditions. Solid-state C-13 NMR and vibrational (IR/Raman) spectroscopic results are also in agreement with the other techniques.
Περιγραφή
Λέξεις-κλειδιά
chemical-shift tensors, molecular-structure, crystal-structure, solid-state, metal-complexes, nmr-spectra, thiamine, vitamin-b1, derivatives, mercury(ii)
Θεματική κατηγορία
Παραπομπή
Σύνδεσμος
<Go to ISI>://A1996VP44900023
http://pubs.acs.org/doi/pdfplus/10.1021/ic950758x
http://pubs.acs.org/doi/pdfplus/10.1021/ic950758x
Γλώσσα
en
Εκδίδον τμήμα/τομέας
Όνομα επιβλέποντος
Εξεταστική επιτροπή
Γενική Περιγραφή / Σχόλια
Ίδρυμα και Σχολή/Τμήμα του υποβάλλοντος
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας