- Rigidity versus Flexibility of Ligands in the Assembly of Entangled Coordination Polymers Based on Bi- and Tetra Carboxylates and N-Donor Ligands
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Seven Zn(II) coordination polymers including [Zn(pbda)(p-bimb)]·H2O (1), [Zn(pbda)(bpa)0.5] (2), [Zn(pbda)(bpp)] (3), [Zn(Hpbda)2(bibm)2] (4), [Zn(pbta)0.5(m-bimb)]·H2O (5), [Zn(pbta)0.5(bpp)(H2O)] (6), and [Zn(H2pbta)(bibm)]·H2O (7) (H2pbda = 4,4′-{[1,4-phenylenebis(methylene)]bis(oxy)}dibenzoic acid; p-bimb = 1,4-bis(1H-imidazol-l-yl)methyl)benzene; bpa = 1,2-bis(4-pyridyl)ethane; bpp = 1,3-bis(4-pyridyl)-propane; bibm = 4,4′-di(1H-imidazol-1-yl)-1,1′-biphenyl; m-bimb = 1,3-bis(1H-imidazol-l-yl)methyl)-benzene; H4pbta = 5,5′-phenylenebis(methylene)-1,1′-3,3′-(benzene-tetracarboxylic acid) were prepared under solvothermal conditions and structurally characterized. Compound 1 shows a three-dimensional (3D) channel-like architecture constructed by helical chain subunits. Compound 2 shows a rare 2D + 2D + 2D → 2D network with both polyrotaxane and polycatenane features. 3 holds a 2D layer structure constituted of metal-sharing right- and left-handed helical chains. Compound 4 presents a one-dimensional (1D) chain which is decorated by long side arms around the chain. Compound 5 possesses a 2D wave-like layer formed by [Zn2(m-bimb)]n chains by linear pbta ligands. Compound 6 displays a 3D framework that is stabilized by hydrogen bonding interactions between the coordinated H2O molecules and the neighboring carboxylate oxygen atoms. Compound 7 possesses a 1D + 1D → 2D polycatenation motif. The results demonstrated that the rigidity versus flexibility of the ligands along with the number of carboxyl groups make an impact on the structural diversities of the entangled coordination polymers. Moreover, compounds 3 and 6 as representative examples possessed high catalytic efficiency for the photodecomposition of methyl blue in water using natural sunlight irradiation. (Figure Presented).
- Wang, Shu-Long,Hu, Fei-Long,Zhou, Ju-Ying,Zhou, Yan,Huang, Qin,Lang, Jian-Ping
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p. 4087 - 4097
(2015/08/18)
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- Synthesis of cyclophanes with intra-annular functionality and cage structure
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Cyclophanes of the type 1 and 2, with large cavity sizes, have been synthesized from the corresponding dichloride 8 or 8a and o-xylene-α,α′-dithiol (9), p-xylene-α,α′-dithiol (10), or m-terphenyldithiol (11). Similarly, cyclophanes of the type 3 with intr
- Kannan, Arunachalam,Rajakumar, Perumal,Kabaleeswaran,Rajan
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p. 5090 - 5102
(2007/10/03)
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- Synthesis and molecular transformations of functionalised cyclophanes with large cavity
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Cyclophanes of the type 1 and 3 are obtained by the coupling of suitable dithiol with corresponding dibromide under high dilution technique in the presence of KOH in benzene or toluene-ethanol. Few molecular transformations have been effected on the cyclo
- Kannan,Rajakumar
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p. 3053 - 3065
(2007/10/03)
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- Bis-carbalkoxy compounds and their preparation
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The invention relates to halogenous polyesters with the recurrent general formula STR1 in which at least part of the R's, e.g. 1 to 100 mole-%, preferably 100 mole-%, or 2 to 10 mole-%, are of the general formulas STR2 and 0 to 99 mole-%, preferably 0 or 90 to 98 mole-%, of the R's correspond to a phenylene radical and/or a naphthylene radical and/or an alkylene radical of 3 to 10 carbon atoms and/or a cycloalkylene radical, and the R's represent an organic moiety which is contained in bivalent saturated alcohols and corresponds to a branched or unbranched saturated alkylene radical of 2 to 10 carbon atoms and/or to a cycloalkylene radical and/or which is derived from an alkyleneterephthalate containing hydroxyl groups, preferably an oligomeric ethyleneterephthalate and/or an oligomeric propyleneterephthalate and/or an oligomeric butyleneterephthalate, wherein Z represents the groups STR3 and X represents hydrogen, bromine or chlorine, wherein at least some of the X's are bromine or chlorine, and in which polyesters, in some cases, a portion of the R's are residues of unsaturated dicarboxylic acid derivatives which, together with ethylenically unsaturated comonomers, preferably styrene, are capable of forming peroxide-curable unsaturated polyester resin (UP resin) solutions, and their preparation as well as their use as fire-retardant molding compositions or articles, and also dicarboxylic acid esters some of which can be used in the preparation of the polyesters as well as the preparation of these dicarboxylic acid esters. Preferably the xylene nucleus in (2) is substituted by Br4.0 to 2.8 and Cl0 to 1.2.
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