The search for novel lanthanide coordination networks using pyrazine N,N'-dioxide (pzdo, C4H4N2O2) as a structure-directing unit, led to the synthesis and the structure determination of the title compound, [Na2(C4H4N2O2)(H2O)6][B(C6H5)4]2·C4H4N2O2·2H2O. The crystal structure is comprised of discrete [{Na(H2O)2}2(μ-H2O)2(μ-pzdo)](2+) cations and tetra-phenyl-borate anions, as well as pzdo and H2...

Proanthocyanidins, also known as condensed tannins or oligomeric flavonoids, are found in many edible plants and exhibit interesting biological activities. Herein, we report a new, simple method for the stereoselective synthesis of procyanidin B6, a (+)-catechin-(4-6)-(+)-catechin dimer, by Lewis acid-catalyzed intramolecular condensation. The 5-O-t-butyldimethylsilyl (TBDMS) group of 5,7,3'4'-...

a new cesium ion selective pvc membrane based on parent calix [4] arene was developed for potentiometric determination of cesium in environmental samples. the electrode based on p-5,11,17,23tetra(tertbutyl) 25,26,27,28-tetrahydroxy calix[4]arene(thc) as ionophor ,dibutyl phthalate (dbp)as plasticizer ,sodium tetra phenyl borate(natpb)and oleic acid as lipophilic salt and additive showed the bes...

In the title compound, trans,trans-[μ-(m-phenyl-ene)bis-(ethyne-1,2-di-yl)]bis-[chlorido(1,4,8,11-tetra-aza-cyclo-tetra-deca-ne)cobalt(III)]-trans,trans-[μ-(5-bromo-m-phenyl-ene)bis-(ethyne-1,2-di-yl)]bis-[chlorido(1,4,8,11-tetra-aza-cyclo-tetra-deca-ne)cobalt(III)]-tetra-phenyl-borate-acetone (0.88/0.12/2/4), [Co(2)(C(12)H(4))Cl(2)(C(10)H(24)N(4))(2)](0.88)[Co(2)(C(10)H(3)Br)Cl(2)(C(10)H(24)N(...

A new chalcone of the coumarin, C(21)H(18)O(7), containing an annulated α-pyrone ring, was obtained by condensation of the borate complex of ac-yl(hydr-oxy)coumarin with trimethoxy-benzaldehyde. The structure exhibits intra-molecular hydrogen bonding between the hydroxyl oxygen and the ketonic oxygen in the coumarin group. The bicyclic coumarin fragment and the benzene ring form a dihedral angl...

Reactions of glycidyl methacrylate with the crown and chair conformers of tetra(4-hydroxyphenyl)calix[4]resorcinarene were studied. The reactions were done over epoxide groups present in the ester, which can easily undergo an opening reaction with hydroxyl groups in the macrocyclic system. Initially, epoxidation reactions were carried out with pure conformers, and it was observed that the react...

The reaction of [Pd(MeCN)(4)](BF(4))(2) with 2,2'-bipyrimidine (bpm) in MeCN-CHCl(3) afforded the title compound, [Pd(C(8)H(6)N(4))(2)](BF(4))(2)·C(2)H(3)N. The asymmetric unit contains two half complexes, with the Pd(II) atoms both lying on a twofold axis. Each metal atom adopts a tetra-hedrally distorted square-planar geometry. In the crystal, [Pd(bpm)(2)] dications are linked by C-H⋯N hydrog...

The title borophosphate LiNi(H(2)O)(2)[BP(2)O(8)]·H(2)O was synthesized under hydro-thermal conditions. The crystal structure is isotypic with the Mg analogue and features helical [BP(2)O(8)](3-) borophosphate ribbons, constructed by BO(4) (2 symmetry) and PO(4) tetra-hedra. The borate groups share all their oxygen apices with adjacent phosphate tetra-hedra. The ribbons are connected via Ni(2+)...

The asymmetric unit of the title compound, C(8)H(6)F(3)N(2) (+)·BF(4) (-)·C(8)H(5)F(3)N(2)·H(2)O, consists of two 2-trifluoro-methyl-benzimidazole mol-ecules, each of which is protonated on a 50% basis, one tetra-fluoro-borate anion and a water mol-ecule. The two 2-trifluoromethylbenzimidazole mol-ecules thus exist as half-neutral half-cation entities. They are linked by N-H⋯N hydrogen bonds in...

In the centrosymmetric title complex, [Cu(2)(C(12)H(10)N(4))(C(18)H(15)P)(4)](BF(4))(2)·2CH(2)Cl(2), the Cu(I) atom adopts a distorted tetra-hedral geometry, defined by two P atoms from two triphenyl-phosphine ligands and two N atoms from a pyridine-2-carbaldehyde azine ligand. The two Cu atoms are bridged by the centrosymmetric pyridine-2-carbaldehyde azine ligand. The F atoms of the tetra-flu...