Thermal behaviour of complexes of antipyrine derivatives II

Parent and mixed ligand complexes of cobalt(II) and copper(II) ions with N,N-bis-(4-antipyrylmethyl)piperazine or N,N-tetra(4-antipyryl-methyl)-1,2-diaminoethane or/and imidazole as ligand and ClO ₄ ^– or SCN^– as counterion were synthesised and their thermal behaviour was investigated.This work was performed in the framework of cooperation between the Hungarian Academy of Sciences and Romanian Academy and was supported financially, in part, by the Hungarian Scientific Research Foundation (OTKA T 029554).     

Poly(N‐vinyl imidazole) grafted silica nanofillers: Synthesis by RAFT polymerization and nanocomposites with polybenzimidazole

In this report, we synthesized poly(N‐vinyl imidazole) (PNVI) grafted silica nanoparticles (SiNP) by using RAFT polymerization through grafting‐from approach to demonstrate that the self‐assembled structure of SiNP is the key diving force in improving physical properties of SiNP based nanocomposites. In a multistep synthetic process, well‐defined PNVI chains with tunable molecular weights and surface chain densities were grown from the RAFT agent anchored SiNP surface using N‐vinyl imidazole (NVI) as a monomer. Spectroscopic and thermal analysis confirmed surface grafting of PNVI on SiNP surface and the amount of grafted PNVI chins were also quantified. The mean diameter of the PNVI grafted SiNP (PNVI‐g‐SiNP) particles altered between 50 and 100 nm with the variation of PNVI chain lengths. The present approach is metal‐catalyst free, straight forward, and provides PNVI functionalized SiNP in a simple manner in comparison to the reported methods. Further, these PNVI‐g‐SiNP particles were used as a nanofiller to prepare nanocomposites with Poly(4,4′‐diphenylether‐5,5′‐bibenzimidazole) (OPBI). These nanocomposites displayed significantly higher mechanical, proton conductivity and less acid leaching properties than the pristine OPBI. The anisotropic self‐assembled ordered structure formation of nanofillers in the nanocomposites believed to be the driving force for the enhanced physical properties. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 365–375     

Model studies of trialkyltin–protein interactions: 13C NMR analysis of solution equilibria of the complex between trimethyltin and methyl N-benzoyl-l-leucyl-l-histidinate

¹³C NMR spectra for the 1:1 complex between methyl N-benzoyl-l-leucyl-l-histidinate and the trimethyltin moiety in d-chloroform (CDC1₃), d₄-methanol (CD₃OD) dimethyl sulphoxide (DMSO) and d₆-DMSO/H₂O solvents are reported, and contrasted with those for the free ligand. The spectra are interpreted in terms of a variety of solution equilibria illustrating the nature of the interaction between the trimethyltin species and primarily the imidazole ring of the histidine residue. Evidence for the preferential stability of pentacoordinate solution structures about tin is presented.     

Tripodal imidazole containing ligands for copper catalyzed ATRP

Tripodal imidazole containing ligands, bis((2‐pyridyl)methyl)(1‐methylimidazole‐2‐yl)methyl)amine (BPIA) and bis(1‐methylimidazole‐2‐yl)methyl)((2‐pyridyl)methyl)amine (BIPA), were synthesized and used for copper catalyzed atom transfer radical polymerization (ATRP) of n‐butyl acrylate (nBA). The molecular weights of poly(n‐butyl acrylate) (PnBA) catalyzed by CuBr/BPIA and CuBr/BIPA complexes increased linearly with nBA conversions and they were close to theoretical values with low polydispersities. ATRP equilibrium rate constant (K_ATRP) measurements showed that bothCuBr/BPIA and CuBr/BIPA complexes had high K_ATRP values, similar to that of CuBr/tri(2‐pyridylmethyl)amine (TPMA), which is one of the ATRP most active ligands. Activators regenerated by electron transfer (ARGET) ATRP of nBA with CuBr₂/BPIA and CuBr₂/BIPA complexes were also conducted and polymerization reached high nBA conversions, resulting in PnBA with low polydispersities. This suggests that the copper complexes with BPIA and BIPA were sufficiently stable and active to conduct ATRP when catalyst concentration was low. ARGET ATRP to form high molecular weight PnBA with CuBr₂/BPIA and CuBr₂/BIPA complexes was also successful. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2015–2024, 2008     

Intercalation of heterocyclic compounds in α-zirconium phosphate: Imidazole,benzimidazole, histamine and histidine

The intercalation of imidazole and some organic species containing the imidazole ring, between the layers of crystalline zirconium phosphate has been investigated. Fourteen new, well-ordered intercalation compounds are obtained with the batch procedure at r.t. and/or 60°C. A mechanism of formation of the various compounds is proposed on the basis of the interaction between the guest molecules (with their dimensions and geometries) and the free PO₃OH groups available between the layers of the host. The new phases have been characterized by TG and X-ray methods.     

2-(4''''-正丙基苯)咪唑并[2,1-α]异喹啉的晶体结构

本文测定了新型抗早孕药物 2-(4'-正丙基苯)咪唑并[2,1-a]异喹啉的晶体结构。该化合物分子式为C20H18N2, Mr = 286.38, 晶体属单斜晶系, 空间群为P21/n, 晶胞参数为a = 7.2177(1), b = 7.8036(2), c = 27.429(1) ? b = 90.976(3), V = 1544.67(8) 3, Z = 4, Dc = 1.231 g/cm3, F(000) = 608.00, m(Mo-Ka) = 0.073 mm-1, R = 0.0560, wR = 0.1440, 获得25986个衍射点,其中独立衍射点3795个。在分子结构中, 苯环(C(1)C(6))与环(N(1), C(1)C(9))以及咪唑环共平面, 该平面与苯环(C(12)C(17)所在平面的夹角为10.014。     

Beyond Molecules: Mesoporous Supramolecular Frameworks Self‐Assembled from Coordination Cages and Inorganic Anions

Biological function arises by the assembly of individual biomolecular modules into large aggregations or highly complex architectures. A similar strategy is adopted in supramolecular chemistry to assemble complex and highly ordered structures with advanced functions from simple components. Here we report a series of diamond‐like supramolecular frameworks featuring mesoporous cavities, which are assembled from metal‐imidazolate coordination cages and various anions. Small components (metal ions, amines, aldehydes, and anions) are assembled into the hierarchical complex structures through multiple interactions including covalent bonds, dative bonds, and weak C? H???X (X=O, F, and π) hydrogen bonds. The mesoporous cavities are large enough to trap organic dye molecules, coordination cages, and vitamin B₁₂. The study is expected to inspire new types of crystalline supramolecular framework materials based on coordination motifs and inorganic ions.