Affinity chromatography of carboxylic proteinases on a polymeric sorbent containing gramicidin-C as ligand

A new polymeric sorbent for proteinases has been synthesized by the radical copolymerization of N-vinylpyrrolidone, bis-N-acryloylgramicidin C, and N,N-methylenebisacrylamide. Biospecific chromatography on the new sorbent has enabled an industrial preparation of procine pepsin to be purified by a factor of 2.5. With the aid of the new sorbent, a carboxylic proteinase has been isolated from the industrial preparation Tsellolignorin with a 15-fold purification factor.M. V. Lomonosov State University. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 215–218, March–April, 1986.     

Sepharose 4B-DNP-hexamethylenediamine as a sorbent for the chromatography of carboxylic proteinases

Summary 1. The chromatography of the carboxylic proteinases porcine pepsin, aspergillopepsin A, and chymosin on the hydrophobic sorbent Sepharose 4B-DNP-hexamethylenediamine has been studied. It has been shown that the nature of the binding of the proteinases with the sorbent depends on the pH.2. A shortening of the length of the carbohydrate chain of the ligand by four methylene units substantially weakens the interaction of pepsin with the sorbent.3. With chymotrypsin and pepsin as examples, the possibility has been shown of using ionic effects for separating these enzymes.M. V. Lomonosov Moscow State University. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 191–199, March–April, 1979.     

Synthesis, Crystal Structure Determination, and Physicochemical Study of the Nickel(II) Complex of 4-(Pyridyl-2)-1,2,4-triazole

A new trinuclear nickel(II) complex with 4-(pyridyl-2)-1,2,4-triazole (pytrz), [Ni₃(pytrz)₆(H₂O)₆](NO₃)₆, has been synthesized, and its crystal structure has been determined. The compound was studied by X-ray phase analysis (XRPA), magnetochemical measurements, and electronic and IR spectroscopy.     

Heat capacity of polynuclear Fe(HTrz)3(B10H10)·H2O and trinuclear [Fe3(PrTrz)6(ReO4)4(H2O)2](ReO4)2 complexes (HTrz=1,2,4-triazole, PrTrz=4-propyl-1,2,4-triazole) manifesting 1A1⇔5T2 spin transition

Low-temperature heat capacity of polynuclear Fe(HTrz)₃(B₁₀H₁₀)·H₂O (I) and trinuclear [Fe₃(PrTrz)₆(ReO₄)₄(H₂O)₂](ReO₄)₂ (II) spin crossover coordination compounds was measured in 80–300 K temperature range using a vacuum adiabatic calorimeter. For I, an anomaly of heat capacity with a maximum at T _trs=234.5 K (heating mode) was observed, Δ_trs H=10.1±0.2 kJ mol^?1 Δ_trs S=43.0±0.8 J mol^? K^?1. For II, a smooth anomaly between 150 and 230 K was found, Δ_trs H=2.5±0.25 kJ mol^?1 Δ_trs S=13.6±1.4 J mol^? K^?1. Anomalies observed in both compounds correspond to ¹A₁?⁵T₂ spin transition.     

Mössbauer study of the influence of ligands and anions of the second coordination sphere in Fe(II) complexes with 1,2,4-triazole and 4-amino-1,2,4-triazole on the temperature of the 1A 1⇆5 T 2 spin transitions

For Fe(II) complexes with 1,2,4-triazole (Tr) and 4-amino-1,2,4-triazole (ATr) in low-spin phases, it has been revealed that the ligand and anion of the second coordination sphere affect the electronic state of the central atom and the symmetry of its local environment. For low-spin phases, a correlation between the Mössbauer spectrum parameters—the chemical shift and the bandwidth of the weakly resolved quadrupole doublet—and the spin transition temperature T_c has been established. The mechanism of the influence of complex composition on the spin transition temperature is accounted for by assuming that T_c is determined by the lattice energy of a complex compound.     

EXAFS study of spin transition effect on the spatial and electronic structure of Fe(II) complexes with triazoles

EXAFS spectroscopy is used to investigate the characteristic features of the spatial and electronic structure of the polynuclear Fe(II) complexes Fe(ATR)₃A₂ (where A is the NO ₃ ^? , BF ₄ ^? , Br^?, or ClO ₄ ^? anion and ATR is 4-amino-1,2,4-triazole) and their magnetically diluted phases Fe_xZn_1?x(ATR)₃(NO₃)₂. The absolute distances from Fe and Zn to the surrounding atoms are determined at temperatures higher and lower than the spin transition point. In all complexes, the spin transition is accompanied by significant changes in the local environment of Fe atoms, while in the magnetically diluted phases the surrounding of zinc remains unchanged. It is shown that addition of Zn atoms distorts the triazole rings in the low-spin state of the complexes. No localized anions were revealed within 3.3 Å from the Fe and Zn atoms. It is shown that a decrease in the spin transition temperature correlates with an increase in Fe?N distances in the low-spin complexes due to magnetic dilution and substitution of anions in the series NO ₃ ^? , BF ₄ ^? , Br^?, ClO ₄ ^? of ATR-containing complexes.     

Crystal Structure of Hexa(μ-bromo)-#x03BC;4-oxo-tetrakis-(1-ethyltetrazole)-tetracopper(II)

The structure of the [Cu₄(-Br)₆(₄-O)(ettz)₄] complex of the monoclinic crystal system was investigated by X-ray diffraction analysis: a = 45.016(12), b = 9.363(4), c = 15.698(5) , = 100.28(2)°, V _cell = 6510(4) ³, space group C2/c, Z = 8,_calc = 2.330 g/cm³, R1 = 0.0697 for 714 F_hkl 4 (F). The copper atoms form a tetrahedron with an oxygen atom in the middle and bromine atoms on the edges. The coordination polyhedron around the copper atom is a distorted trigonal bipyramid (CuOBr₃N unit). All tetrazole ligands are monodentate and coordinated by the N⁴ atoms.     

Crystal structure and quantum chemical investigation of 4-(3,4-dichlorphenyl)-1,2,4-triazole

1,2,4-Triazole derivative substituted in the 4th position — 4-(3,4-dichlorphenyl)-1,2,4-tirazole — has been synthesized. Crystal and molecular structure of the compound were determined by single crystal X-ray diffraction. Molecular geometry optimization and effective charge calculations were performed by DFT methods.     

Complexes of cobalt(2+) chloride with hydrochlorides of N-(1,2,4-triazol-5-yl)- and N-(tetrazol-5-yl)benzamidines

We have synthesized complex compounds of Co(2+) chloride with hydrochlorides of N-(1,2,4-triazol-5-yl)benzamidine and N-(tetrazol-5-yl)benzamidine. According to magnetochemistry and electron spectroscopy data, the ligands are coordinated in a bidentate fashion with the N atom of the amidine group and the N atom of the heterocycle with formation of the tetrahedral chromophore CoN₂Cl₂.Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk. N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2311–2315, October, 1992.     

Co(II), Ni(II) and Cu(II) Complexes with 1-(4-Hydroxyphenyl)-1H-1,2,4-Triazole

New complexes of Co(II), Ni(II), and Cu(II) with 1-(4-hydroxyphenyl)-1H-1,2,4-triazole (L) of the composition ML₂(H₂O)₂(NO₃)₂ · nH₂O (M = Co(II), n = 3; M = Ni(II), n = 0; M = Cu(II), n = 0) were synthesized and studied by photoelectron and IR spectroscopy, magnetochemistry, thermogravimetry, and X-ray powder diffraction analysis. The type of _eff(T) relationship suggests that paramagnetic centers in the Co(II) chloride and Cu(II) nitrate and bromide complexes are involved in antiferromagnetic exchange interactions. The exchange energy values were estimated by the molecular field method.