Enhanced faradic activity by construction of p-n junction within reduced graphene oxide@cobalt nickel sulfide@nickle cobalt layered double hydroxide composite electrode for charge storage in hybrid supercapacitor.

The intrinsic faradic reactivity is the uppermost factor determining the charge storage capability of battery material, the construction of p-n junction composing of different faradic components is a rational tactics to enhance the faradic activity. Herein, a reduced graphene oxide@cobalt nickle sulfide@nickle cobalt layered double hydroxide composite (rGO@CoNi2S4@NiCo LDH) with p-n junction structure is designed by deposition of n-type nickle cobalt layered double hydroxide (NiCo LDH) around p-type reduced graphene oxide@cobalt nickle sulfide (rGO@CoNi2S4), the charge redistribution across the p-n junction enables enhanced faradic activities of both components and further the overall charge storage capacity of the resultant rGO@CoNi2S4@NiCo LDH battery electrode. As expected, the rGO@CoNi2S4@NiCo LDH electrode can deliver high specific capacity (Cs, 1310 ± 26 C g-1 at 1 A g-1) and good cycleability (77% Cs maintaining ratio undergoes 5000 charge-discharge cycles). Furthermore, the hybrid supercapacitor (HSC) based on the rGO@CoNi2S4@NiCo LDH p-n junction battery electrode exports high energy density (Ecell, 57.4 Wh kg-1 at 323 W kg-1) and good durability, showing the prospect of faradic p-n junction composite in battery typed energy storage.

Structure and third-order nonlinear optical properties of the two-dimensional CoII coordination polymer [Co(1,2-BIB)(PA)]n {1,2-BIB is 1,2-bis[(1H-imidazol-1-yl)methyl]benzene and H2PA is phthalic acid}.

The design of nonlinear optical (NLO) materials with large NLO responses has been a challenge for materials scientists and chemists. Recently, organic polymers have received attention regarding their NLO properties and fast nonlinear response, and clusters involving delocalized dπ-pπ systems and conjugated dπ-pπ systems are expected to be a new class of NLO materials. Metal-organic coordination polymers combine the advantages of the organic and inorganic species. Thus far, tuning the third-order NLO properties of these materials has been a significant challenge. A two-dimensional coordination polymer, namely poly[(µ-benzene-1,2-dicarboxylato-κ3O1,O1':O3){µ-1,2-bis[(1H-imidazol-1-yl)methyl]benzene-κ2N3:N3'}cobalt(II)], [Co(C8H4O4)(C14H14N4)]n, was synthesized by hydrothermal methods. In the structure, the CoII ion is pentacoordinated by two N atoms from two different 1,2-bis[(1H-imidazol-1-yl)methyl]benzene (1,2-BIB) ligands and three O atoms from two symmetry-related benzene-1,2-dicarboxylate (isophthalate, PA) anions. The pentacoordinated CoII ions are linked by PA ligands to form a chain structure parallel to the c axis. Adjacent chains are further connected by 1,2-BIB ligands to produce a two-dimensional layered structure. The compound exhibits strong third-order nonlinear absorption and nonlinear refraction effects as a thin film. The third-order susceptibility χ(3) is calculated to be 1.07 × 10-8 esu, which is much larger than the values found for pure inorganic semiconductors and some polymers.

Enhanced third-order nonlinear optical properties determined in thin films using the Z-scan technique: bis(µ-4,4'-oxydibenzoato)bis[(4'-phenyl-2,2':6',2''-terpyridine)cobalt(II)].

π-Conjugated organic materials exhibit high and tunable nonlinear optical (NLO) properties, and fast response times. 4'-Phenyl-2,2':6',2''-terpyridine (PTP) is an important N-heterocyclic ligand involving π-conjugated systems, however, studies concerning the third-order NLO properties of terpyridine transition metal complexes are limited. The title binuclear terpyridine Co(II) complex, bis(µ-4,4'-oxydibenzoato)-κ(3)O,O':O'';κ(3)O'':O,O'-bis[(4'-phenyl-2,2':6',2''-terpyridine-κ(3)N,N',N'')cobalt(II)], [Co2(C14H8O5)2(C21H15N3)2], (1), has been synthesized under hydrothermal conditions. In the crystal structure, each Co(II) cation is surrounded by three N atoms of a PTP ligand and three O atoms, two from a bidentate and one from a symmetry-related monodentate 4,4'-oxydibenzoate (ODA(2-)) ligand, completing a distorted octahedral coordination geometry. Neighbouring [Co(PTP)](2+) units are bridged by ODA(2-) ligands to form a ring-like structure. The third-order nonlinear optical (NLO) properties of (1) and PTP were determined in thin films using the Z-scan technique. The title compound shows a strong third-order NLO saturable absorption (SA), while PTP exhibits a third-order NLO reverse saturable absorption (RSA). The absorptive coefficient ß of (1) is -37.3 × 10(-7) m W(-1), which is larger than that (8.96 × 10(-7) m W(-1)) of PTP. The third-order NLO susceptibility χ((3)) values are calculated as 6.01 × 10(-8) e.s.u. for (1) and 1.44 × 10(-8) e.s.u. for PTP.

catena-Poly[[[2-(2-chlorophenoxy)-N'-(2-oxidobenzylidene-κO)acetohydrazidato-κ2N',O]copper(II)]-µ-morpholine-κ2N:O].

In the title compound, {[Cu(C15H11ClN2O3)(C4H9NO)]n, the Cu(II) cation has square-pyramidal geometry. The morpholine ligand serves as a bridge to link two symmetry-related metal atoms, resulting in an infinite chain structure along the a axis. Adjacent chains are extended into a two-dimensional layered structure via hydrogen bonds formed between morpholine and amide N atoms [N-H···N = 2.971 (3) Å].

The crystal structure of the 1:1 inclusion complex of beta-cyclodextrin with benzamide.

The 1:1 inclusion complex of beta-cyclodextrin and benzamide was prepared and characterized by single crystal X-ray diffraction, PXRD, TGA, and IR. This complex crystallizes in the monoclinic P2(1) space group with unit cell constants a=15.4244(16), b=10.1574(11), c=20.557(2)A, beta=110.074(2) degrees , V=3025.1(6)A(3). The guest molecule projects into the beta-cyclodextrin cavity from the primary hydroxyl side. The amide group protrudes from the primary hydroxyl side and forms hydrogen bonds with the adjacent beta-cyclodextrin molecule. There are six crystallized water molecules, which play crucial roles in crystal packing.

Dipotassium aquapentafluorovanadate.

The title compound, K(2)[VF(5)(H(2)O)], was synthesized from potassium antimony tartrate, piperazine, V(2)O(5) and HF under hydrothermal conditions. It is isostructural with K(2)[FeF(5)(H(2)O)] and contains polymeric anion chains held together by strong O-H...F bonds. Each V atom is coordinated to five terminal F atoms and the O atom of one water molecule. Pairs of O-H...F bonds are formed by two cis-related F atoms. Twofold axes run along the O-V-F axis of the V-centred otahedra.