6,382 research outputs found
Clinical question: does physical therapy improve menopausal symptoms for a perimenopausal woman?
No full text
Homochiral transition-metal camphorate coordination architectures containing "piperazine-pyridine" ligands
No full text[[abstract]]A total of five homochiral metal-organic coordination polymers (MOCPs) showing high thermal stability have been assembled from the reaction of divalent transition-metal ions (Co(2+), Zn(2+), and Cd(2+)), rigid enantiopure D-camphoric acid (D-H(2)Cam), and achiral neutral N,N'-bis(pyrid-4-yl) piperazine (bpypip) ligand under hydro(solvo)thermal conditions. Compound [Co(2)(D-Cam)(2)(bpypip)] (1) features a chiral-layered cobalt-camphorate coordination (4,4)-net, which is pillared by auxiliary linear N-tethering bpypip linkers to yield a homochiral three-dimensional coordination framework with Schlafli symbol of 4(4).6(10).8. Compounds [M(D-HCam)(2)(bpypip)] (2, M = Cd; 3, M = Zn) have nearly identical one-dimensional M-bpypip zigzag coordination-chain structures, in which each metal ion further attaches to two partially deprotonated monoanionic D-HCam terminals, which exhibit two types of partially deprotonating manner in 2 but only one type in 3. Through chain-to-chain C(= O)OH center dot center dot center dot O(carboxylate) hydrogen bonds, the zigzag coordination-chain becomes extended to a three-dimensional uninodal 6-connected supramolecular network, which can be considered as a result of a M-D-HCam-based 4-connected supramolecular 6(5).8-net intersected by M-bpypip-based zigzag coordination-chains. Of particular interest, the supramolecular assembly contains a couple of single-stranded right- (SRH) and left-handed (SLH) supramolecular helices and a couple of double-stranded right-(DRH) and left-handed (DLH) supramolecular helices, and therefore exists as a meso-net in topology, i.e., there is no spatial chirality. Compounds [M(2)(OH)(OAc)(D-Cam)(bpypip)] (4, M = Co; 5, M = Zn) have identically homochiral ladder-like chain structures having meso-M2 units and presenting three kinds of different anions, i.e., hydroxyl, acetate, and D-Cam. The obtained acetate anion may be generated from the hydrolyzation of dimethylacetamide (DMAc) under hydro(solvo) thermal conditions.[[note]]SC
The interaction of estrogen receptor alpha and caveolin-3 regulates connexin43 phosphorylation in metabolic inhibition-treated rat cardiomyocytes.
No full textDiscrete and Infinite Metallacyclic Coordination Architectures Based on a Conformationally Flexible Tripodal Aminotriazine-Derived Polypyridyl Ligand
No full text[[abstract]]A novel tripodal semi-rigid ligand, 2,4,6-tris(3-picolylamino)-1,3,5-triazine (m-H(3)tpat), consisting of a triazine central core and three pyridine donating functions attached to flexible NHCH2- arms has been designed and synthesized. The self-assembly reactions of m-H(3)tpat with copper(II) chloride and cobalt(II) chloride yielded discrete Cu-II complex [Cu2Cl4(m-H(3)tpat)(2)]center dot 2H(2)O center dot 2EtOH (1 center dot 2H(2)O center dot 2EtOH) and polymeric Co-II complex [Co(m-H(3)tpat)(2)(H2O)(2)]Cl-2 (2), respectively. Complex 1 has a metallacyclophane structure with a metal-to-ligand ratio of 2:2. Each copper(II) ion adopts a pentacoordinate square-pyramidal geometry with a N3Cl2 coordination sphere. Complex 2 exhibits an extended chain structure based on {Co-2(m-H(3)tpat)(2)} metallacyclic repeating units. Each cobalt(II) ion adopts a hexacoordinate octahedral geometry with a N2O4 coordination environment. Note that the m-H(3)tpat ligand exists in a cis-cis-cis conformation in 1 and a cis-trans-trans conformation in 2, with the central aminotriazine moiety appearing to be an asymmetric-configured allamino tautomer in both conformers. The stabilities of the two coordination-directed structures may be enhanced by intramolecular p-p interactions between two pyridine rings from two different m-H(3)tpat ligands within the metallacyclophane structure of 1 and by a set of complementary double hydrogen bonds (DA-AD arrays) between two aminotriazine moieties of two m-H(3)tpat ligands within a metallacyclic unit for 2.[[note]]SC
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