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Min Xia – One of the best experts on this subject based on the ideXlab platform.
Crystal structures and spectroscopic analyses of two Co(II) N 6-Benzylaminopurine supramoleculesJournal of Coordination Chemistry, 2012Co-Authors: Min Xia, Tian-tian Chen, Bu-shun Shan, Chun-li WeiAbstract:
Two mononuclear Co(II) N 6-Benzylaminopurine compounds, [Co(6-BA-H2)2(H2O)4] · (R)2 · 4.5H2O (1) and [Co(6-BA-H)2(H2O)Cl3]Cl · H2O (2) (6-BA = N 6-Benzylaminopurine (C5H2N3NH)(NH)CH2(C6H5), H3R = 5-sulfosalicylic acid (C6H3)CO2H(OH)SO3H), are reported. Compound 1 possesses a 3-D supramolecular structure built via H-bond and π–π stacking interactions that contains a mononuclear six-coordinate [Co(6-BA-H2)2(H2O)4]6+. Compound 2 also exhibits a 3-D supramolecular framework with mononuclear six-coordinate cation [Co(6-BA-H)2(H2O)Cl3]+. Luminescence studies at room temperature show that 1 (λ ex = 268 nm) displays two strong fluorescent emissions centered at 326.8 nm and 356.9 nm, while 2 (λ ex = 233 nm) exhibits a weaker peak emitted at 342.8 nm upon 6-BA-complexation of two different second ligands H3R/Cl− with Co(II).
Crystal and molecular structure of adduct of 6-Benzylaminopurine and 5-sulfosalicylic acidCrystallography Reports, 2010Co-Authors: Min XiaAbstract:
The crystal structure of adduct of 6-Benzylaminopurine and 5-sulfosalicylic acid C19H25N5O10S 1 is studied using single-crystal diffraction (R = 0.0482 for 2852 reflections with I > 2σ(I)). The asymmetric unit of 1 contains one 6-Benzylaminopurine molecule and one 5-sulfosalicylic acid molecule, as well as four lattice water molecules. Hydrogen bonds, formed by 6-Benzylaminopurine and 5-sulfosalicylic acid, link the two molecules into one-dimensional chain (omitting four water molecules), further joined to two-dimensional layer network. Short ring-interactions with intra-chain π-π stacking are observed. The data of IR spectroscopy confirm the formation of the two-dimensional supramolecular layer structure. At last, a 3D supramolecular network constructs via hydrogen bonds.
Synthesis and Crystal Structure of Hydrate Adduct of 6-Benzylaminopurine and 5-Sulfosalicylic Acid [(C12H12N5)(C7H5O6S)·H2O]Journal of Chemical Crystallography, 2010Co-Authors: Min Xia, Yulan ZhuAbstract:
The crystal structure of hydrate adduct of 6-Benzylaminopurine and 5-sulfosalicylic acid [(C12H12N5)(C7H5O6S)·H2O] 1 is studied. It crystallizes in monoclinic system space group P21/n with a = 6.2128(9) A, b = 20.762(3) A, c = 15.675(2) A, β = 92.040(2)°, V = 2,020.6(5) A3, Z = 4, R gt(F) = 0.0494, wR ref(F 2) = 0.1112, and T = 173(2) K. Single-crystal X-ray diffraction analysis reveals that the asymmetric unit of 1 contains one 6-Benzylaminopurine molecule and one 5-sulfosalicylic acid molecule, as well as one lattice water molecule. In 1, hydrogen bonds link the two monomers into one-dimensional double chain, two-dimensional layer network, and further a 3-D supramolecular network. Short ring-interactions with intra-chain π–π stacking are observed (distances between ring centroids are 3.964, 3.796 and 3.571 A, and the dihedral angle between planes are 6.97°, 5.55°, and 5.66°, respectively). A novel hydrate adduct [(C12H12N5)(C7H5O6S)·H2O] 1, has been synthesized and consists of 6-Benzylaminopurine and 5-sulfosalicylic acid molecules with one lattice water molecule. The monomers connect with each other via intermolecular hydrogen bonds C(N, O)–H···O(N) to form double chain, further two-dimensional layer, at last 3-D supramolecular structure network, along with π–π interactions within 4 A.
Libuše Trnková – One of the best experts on this subject based on the ideXlab platform.
Copper complexes of 6-aminopurine and 6-Benzylaminopurine inaqueous methanol solutions, 2015Co-Authors: Iveta Pilařová, Libuše Trnková, Rudolf Navrátil, Přemysl LubalAbstract:
In order to follow many biological processes it is important to understand the interactions between nucleic acids and their constituents with metal ions. It is known that adenine shows various probabilities of coordination with transition metal ions due to its potential donor sites. Electronically favoured coordination sites N(1) and N(3) for the metals were added by the nitrogens N(3) and N(9) due to tautomerization of the imidazole hydrogen atom between N(7) and N(9). In this contribution the protonation and stability constants of 6-aminopurine )adenine) or 6-Benzylaminopurine (BAP) and their copper complexes were determined potentiometrically by using the titrator Titrando 835 controlled by tiamo 1.2 (Metrohm, Switzerland). The experiemnts were hampered by BAP solubility and all the potentiometric experimets were conducted in aqueous methanol solutions (10% v/v CH3OH in water). The stability constants of the copper complexes were calculated for different ligand (purine):metal (copper) ratios according to the Sigel procedure. Potentiometric titrations at different temperature and at the same ionic strength (0.1 M NaCl) enabled the thermodynamic evaluation of changes in enthalpy and entropy of the complexation process. The temperature icrease leads to a decrease in the values of the stability constants suggesting an exothermic behaviour for the complexation process. On the base of thermodynamic data obtained for adenine and BAP the differences were attributed to the effect of the benzyl moiety.
Oxidation of 6‐Benzylaminopurine‐Copper(I) Complex on Pencil Graphite ElectrodeElectroanalysis, 2012Co-Authors: Núria Serrano, Arístides Alberich, Libuše TrnkováAbstract:
A voltammetric study of the 6-Benzylaminopurine (BAP)/Cu(I) system is performed. BAP is an adenine-type cytokinin that elicits cell division in plants and presents antitumor activity when forming complexes with different transition metal ions as copper(I). In the frame of this research field, an analysis of linear sweep voltammetry (LSV), adsorptive stripping voltammetry (AdSV), and elimination voltammetry with linear scan (EVLS) data obtained with a pencil graphite electrode (PeGE), allows us to propose the stoichiometry of the possible complexes formed and the mechanism for total electrode reactions of the BAP/Cu(I) system.
Potentiometric and Voltammetric Study of 6-Benzylaminopurine and Its DerivativesElectroanalysis, 2012Co-Authors: Iveta Pilarova, Přemysl Lubal, Libuše TrnkováAbstract:
The protonation-deprotonation equilibrium of 6–benzylaminopurine (6–BAP) and its derivatives was studied by potentiometry and voltammetry. The effect of Cl or OCH3 group position in 2′, 3′ and 4′ of the benzene ring of 6–BAP on both pKa values was investigated. To determine the enthalpy and entropy, the temperature dependence of pKa was employed. It was found that with increasing temperature the pKa decreased. In comparison with 6–BAP the chloro- or methoxy- group on the benzene ring resulted in pKa increase, and in the case of both derivatives the pKa values decreased with increasing distance of the chloro- or methoxy- moiety from the aminopurine structure. The first pKa values were also determined by linear sweep voltammetry (LSV) and elimination voltammetry with linear scan (EVLS). New approaches were shown not only for the determination of pKa from voltammetric titration curves but also for the evaluation of the reduction processes of benzylaminopurines.
Gao Sheng-li – One of the best experts on this subject based on the ideXlab platform.
Thermochemistry of copper complex of 6-BenzylaminopurineJournal of Thermal Analysis and Calorimetry, 2008Co-Authors: Y. Xuwu, Z. Hang-guo, S. Wu-juan, W. Xiao-yan, Gao Sheng-liAbstract:
The copper(II) complex of 6-Benzylaminopurine (6-BAP) has been prepared with dihydrated cupric chloride and 6-Benzylaminopurine. Infrared spectrum and thermal stabilities of the solid complex have been discussed. The constant-volume combustion energy, ΔcU, has been determined as −12566.92±6.44 kJ mol−1 by a precise rotating-bomb calorimeter at 298.15 K. From the results and other auxiliary quantities, the standard molar enthalpy of combustion, ΔcHmθ, and the standard molar of formation of the complex, ΔfHmθ, were calculated as −12558.24±6.44 and −842.50±6.47 kJ mol−1, respectively.