Complexes of several transition metal ions with alpha-oximinoacetoacetyl pyridine-4-phenylthiosemicarbazone (H3OAPT) have been prepared. Attempts were made to elucidate their geometries by elemental analysis, molar conductance, magnetic measurements and by some spectroscopic (IR, ESR and electronic) techniques. All the investigated metal ions form mononuclear complexes except for CuII, which fo...

The formation of H-addition radicals in monocrystals of adenosine, adenosine-HCl, adenine-HCl-1/2H2O, and adenine-2 HCl by X-irradiation has been st-died by using electron spin resonance spectroscopy at 9.5 GHz and at 35 GHz. In all crystals, both H-addition radicals at position C2 and at position C8 were observed. The coupling constants of these two H-addition radicals are different and depend...

4-(2-Methylbutyl)aminodipicolinic acid (H(2)MEBADPA) has been synthesized and fully characterized in terms of aqueous phase protonation constants (pK(a)'s) and photophysical measurements. The pK(a)'s were determined by spectrophotometric titrations, utilizing a fully sealed titration system. Photophysical measurements consisted of room temperature fluorescence and frozen solution phosphorescenc...

Protonation constants for the biologically-important thioamino acids cysteine (CSH), penicillamine (PSH) and glutathione (GSH), and the formation constants of their complexes with Cu(I), have been measured at 25 °C and an ionic strength of 1.00 mol dm(-3) (Na)Cl using glass electrode potentiometry. The first successful characterisation of binary Cu(I)-CSH and Cu(I)-GSH species over the whole pH...

Bu çalışmada, trisiklik antidepresanlara alternatif olarak kullanılan selektif serotonin geri alım inhibitörleri (SSRİ)’nden sitalopram, fluvoksamin ve sertralinin su-asetonitril ikili karışımında, ters faz sıvı kromatografik (RPLC) yöntemle alıkonma davranışı incelenmiştir. Kromatografik analizler, mobil pH’sı 6,5 ila 10,5 arasında değişen, %45-%55 (h/h) asetonitril içeren asetonitril-su karış...

Recently we have reported a 13C n.m.r. investigation on the site of protonation in the diazanaphthalenes.' This group of N-heterocycles consists of ten compounds: cinnoline (1,2-diazanaphthalene, l), quinazoline (1,3-diazanaphthalene, 2), quinoxaline (1,4-diazanaphthalene, 3), 1 ,5-naphthyridine (1,5diazanaphthalene,4), 1,6-naphthyridine (1,6-diazanaphthalene, 3, 1,7-naphthyridine (1,7-diazanap...

UV absorption spectra and circular dichroism spectra of aqueous solutions of cytosinand thymine-containing single-stranded Oligodeoxyribonucleotide 5'-CCTTTCCTTTTCCTTTCC-3'(ckit4) were measured at various рН in the range 3.3–8.9. The chemometric analysis of the multiinstrumental data matrix was carried out. The diagrams of relative contents of complex forms of the DNA molecule absorbing in the ...

When protons are exchanging for bivalent cations (Cu(2+), Zn(2+), or Ca(2+)) on the carboxylic groups of Nitella flexilis cell wall, the values of the respective global equilibrium constants do not change up to a protonation degree of 80%. These values drastically increase at higher proton concentrations and tend to approximately 3.4, which is the intrinsic pK value of the constitutive alpha-d-...

A new class of 4H-imidazoles was synthesized starting from fused-ring aromatic dinitriles. Strong bathochromic shifts of the longest wavelength absorptions were observed in the corresponding UV/vis spectra due to a conversion of the merocyanine chromophores into cyanines/(aza)oxonoles upon protonation/deprotonation of the 4H-imidazoles. Novel boratetraazapentalenes were synthesized via a cycliz...