ABSTRACT
Sn-based anode materials have become potential substitutes for commercial graphite anode due to their high specific capacity and good safety. In this paper, ultrafine Sn nanoparticles embedded in nitrogen and phosphorus codoped porous carbon nanorods (Sn@C) are obtained by carbonizing bacteria that adsorb the Sn electroplating sludge extracting solution. The as-prepared Sn@C rod-shaped composite exhibits superior electrochemical Li-storage performances, such as a reversible capacity of approximate 560 mAh/g at 1 A/g and an ultralong cycle life exceeding 1500 cycles, with approximately no capacity decay. The ultrastable structure of the Sn@C was revealed using in situ transmission electron microscope at the nanoscale and indicated that the Sn@C composite could restrict the volume expansion of Sn nanoparticles during the lithiation/delithiation cycles. This work provides a new insight into addressing the electroplating sludge and designing novel lithium ion battery anodes.
ABSTRACT
Four mononuclear Cu(i)-halide complexes containing phosphines and pyridine ligands with strong electron donor substituents, [CuCl(PPh3)2(4-NMe2py)] (1), [CuI(PPh3)2(4-NH2py)] (2), [CuI(POP)(4-NH2py)] (3), and [CuI(POP)(4-NMe2py)]·0.5(Et2O) (4), (PPh3 = triphenylphosphine, 4-NMe2py = 4-(dimethylamino)pyridine, POP = bis[(2-diphenyl-phosphino)phenyl]ether, 4-NH2py = 4-aminopyridine, Et2O = diethyl ether) were synthesized and studied with regard to their structural, photophysical properties and theoretical calculations. The complexes exhibit pure blue thermally activated delayed fluorescence (λmax = 442 (1), 436 (2), 464 (3), and 448 nm (4)) in crystalline at room temperature. Emission lifetime analyses and density functional theory (DFT) calculations show that the blue-light emission at room temperature is the singlet (metal + halide)-to-ligand charge transfer state, (1(M + X)LCT), while that at 77 K is the state of 3(M + X)LCT transition character, owing to the small singlet-triplet energy gaps (ΔE = 660-1680 cm-1). X-ray diffraction structure analysis, photophysical studies and theoretical calculations suggest that the much larger torsion angle between the N-heterocyclic rings and N-Cu-X planes of complex 3 than that of 1, 2 and 4 might causes the bathochromic shift of luminescence, although these complexes containing similar heterocycle ligands.
ABSTRACT
The title compound, {[Ag(C6H7AsNO3)(C18H15P)]·H2O}n, has been synthesized from the reaction of 4-aminophenylarsonic acid with silver nitrate, in aqueous ammonia, with the addition of triphenylphosphane (PPh3). The Ag(I) centre is four-coordinated by one amino N atom, one PPh3 P atom and two arsonate O atoms, forming a severely distorted [AgNPO2] tetrahedron. Two Ag(I)-centred tetrahedra are held together to produce a dinuclear [Ag2O2N2P2] unit by sharing an O-O edge. 4-Aminophenylarsonate (Hapa(-)) adopts a µ3-κ(3)N:O:O-tridentate coordination mode connecting two dinuclear units, resulting in a neutral [Ag(Hapa)(PPh3)]n layer lying parallel to the (101Ì) plane. The PPh3 ligands are suspended on both sides of the [Ag(Hapa)(PPh3)]n layer, displaying up and down orientations. There is an R2(2)(8) hydrogen-bonded dimer involving two arsonate groups from two Hapa(-) ligands related by a centre of inversion. Additionally, there are hydrogen-bonding interactions involving the solvent water molecules and the arsonate and amine groups of the Hapa(-) ligands, and weak π-π stacking interactions within the [Ag(Hapa)(PPh3)]n layer. These two-dimensional layers are further assembled by weak van der Waals interactions to form the final architecture.
ABSTRACT
The title compound, {[Zn4(C8H4O4)3(OH)2(C12H6N2O2)2]·2H2O}n, has been prepared hydrothermally by the reaction of Zn(NO3)2·6H2O with benzene-1,4-dicarboxylic acid (H2bdc) and 1,10-phenanthroline-5,6-dione (pdon) in H2O. In the crystal structure, a tetranuclear Zn4(OH)2 fragment is located on a crystallographic inversion centre which relates two subunits, each containing a [ZnN2O4] octahedron and a [ZnO4] tetrahedron bridged by a µ3-OH group. The pdon ligand chelates to zinc through its two N atoms to form part of the [ZnN2O4] octahedron. The two crystallographically independent bdc(2-) ligands are fully deprotonated and adopt µ3-κO:κO':κO'' and µ4-κO:κO':κO'':κO''' coordination modes, bridging three or four Zn(II) cations, respectively, from two Zn4(OH)2 units. The Zn4(OH)2 fragment connects six neighbouring tetranuclear units through four µ3-bdc(2-) and two µ4-bdc(2-) ligands, forming a three-dimensional framework with uninodal 6-connected α-Po topology, in which the tetranuclear Zn4(OH)2 units are considered as 6-connected nodes and the bdc(2-) ligands act as linkers. The uncoordinated water molecules are located on opposite sides of the Zn4(OH)2 unit and are connected to it through hydrogen-bonding interactions involving hydroxide and carboxylate groups. The structure is further stabilized by extensive π-π interactions between the pdon and µ4-bdc(2-) ligands.
ABSTRACT
Circular dichroism is known to be the feature of a chiral agent which has inspired scientist to study the interesting phenomena of circularly polarized light (CPL) modulated molecular chirality. Although several organic molecules or assemblies have been found to be CPL-responsive, the influence of CPL on the assembly of chiral coordination compounds remains unknown. Herein, a chiral coordination polymer, which is constructed from achiral agents, was used to study the CPL-induced enantioselective synthesis. By irradiation with either left-handed or right-handed CPL during the reaction and crystallization, enantiomeric excesses of the crystalline product were obtained. Left-handed CPL resulted in crystals with a left-handed helical structure, and right-handed CPL led to crystals with a right-handed helical structure. It is exciting that the absolute asymmetric synthesis of a chiral coordination polymer could be enantioselective when using CPL, and provides a strategy for the control of the chirality of chiral coordination polymers.
Subject(s)
Lasers , Polymers/chemical synthesis , Circular Dichroism , Polymers/chemistry , StereoisomerismABSTRACT
In this paper, four silver(I) compounds, namely, {[Ag(4)(bipy)(4)(chda)]·2NO(3)·10H(2)O}(n) (1), {[Ag(2)(bipy)(2)(chda)]·14H(2)O}(n) (2), {[Ag(2)(bipy)(2)(chda)]·3EG·2H(2)O}(n) (3) and {[Ag(2)(bipy)(2)(chda)]·H(2)chda}(n) (4) (where bipy = 4,4'-bipyridine, H(2)chda = trans-cyclohexane-dicarboxylate and EG = ethylene glycol), have been synthesized and characterized by single-crystal X-ray diffraction analyses. In all of these compounds, the Ag(I) centers are linked by bipy ligands to form 1D Ag(I)-bipy chain structures. The chda(2-) anions of compound 1 adopt a µ(4)-coordination mode to connect the Ag(I)-bipy chains, forming a H-beam-like chain. In 2, the chda(2-) anions adopt a µ(2)-coordination mode to connect the Ag(I)-bipy chains resulting in two distinct 2D brick wall-like layers. These layers are further stacked in an ···ABAB··· fashion through interlayer π···π stacking interactions giving rise to a 3D framework consisting of quasi-rectangular channels, in which an unusual double T5(2) water tape is trapped. For 3 and 4, the chda(2-) anions show a similar µ(4)-coordination mode to that of 1 and connect the Ag(I)-bipy chains to form 2D grid layers with identical compositions and connective topologies. The experimental studies show that the final structures are greatly influenced by the molar ratio of the components and the solvents, which can be rationally interpreted by the existence of various supramolecular interactions between the host and guest molecules within these compounds through a systematic structural comparison. Additionally, the thermal stability and luminescent properties of these compounds were also studied.
ABSTRACT
A new organically templated vanadium tellurite, poly[2,2'-iminodiethanaminium [hexa-mu2-oxido-tetraoxidoditellurium(IV)divanadium(V)] dihydrate], {(C4H15N3)[Te2V2O10].2H2O}n, features the interconnection of distorted [VO5] trigonal bipyramids by bridging [TeO3] pyramids, leading to a two-dimensional corrugated anionic layer with an interlayer distance of about 13.47 A. The interlayer space is occupied by doubly protonated diethylenetriamine cations (H2dien) and guest water molecules. The two terminal amino groups of H2dien are protonated, while the middle amino group, located on a twofold rotation axis, is not protonated. All the three amino groups and water molecules are involved in hydrogen-bonding interactions. The compound represents a new member in the series (H2am)[(VO2)(TeO3)]2.xH2O, where H2am represents a doubly protonated diamine. Similarities and differences between the structures of members of the series are discussed.
ABSTRACT
The title compound, poly[propane-1,3-diaminium hexa-mu-oxido-dioxidotellurium(IV)divanadium(V)], (C3H12N2)[V2O8Te] or (H2pn)[V2TeO8] (pn is propane-1,3-diamine), contains a two-dimensional anionic layer and the diprotonated pn cation for charge compensation. The anionic layer consists of pyrovanadates and [TeO3] pyramids, which are linked alternately through corner-sharing to form a one-dimensional chain. These one-dimensional chains are crosslinked through two weak Te-O bonds, constructing an anionic layer. Hydrogen bonds are observed involving the diprotonated pn cation and the O atoms of the anionic framework.
ABSTRACT
In the polymeric title compound, [Zn(C(7)H(9)NO(7)P(2))](n), the zinc(II) centre displays a tetra-hedral coordination geometry provided by four O atoms from three different phospho-nate groups. The crystal structure consists of ladder chains parallel to the b axis built up from vertex-sharing of ZnO(4) and PO(3)C tetra-hedra. The chains are linked by strong intra- and inter-chain O-Hâ¯O and N-Hâ¯O hydrogen bonds, forming a three-dimensional supra-molecular assembly.
ABSTRACT
In the title compound, [Pb(C(6)H(4)NO(2))(N(3))(H(2)O)](n), the Pb ion is seven-coordinated by three N atoms from three azide ligands, two O atoms from two isonicotinate (inic) ligands and two O atoms from two coordinated water molecules, forming a distorted monocapped triangular prismatic coordination geometry. Each azide ligand bridges three Pb(II) ions in a mu(1,1,3) coordination mode to form a two-dimensional three-connected 6(3) topology network extending in the bc plane. The carboxylate group of the inic unit and the aqua ligand act as coligands to bridge Pb(II) ions. Adjacent two-dimensional layers are connected by hydrogen-bonding interactions between the isonicotinate N atom and the water molecule, resulting in an extended three-dimensional network. The title complex is the first reported coordination polymer involving a p-block metal, an azide and a carboxylate.
ABSTRACT
The title compound, [Cu(2)Fe(3)(C(5)H(5))(3)(C(2)H(3)O(2))(C(6)H(4)O(2))(3)(C(3)H(7)NO)(2)], belongs to the classic dimeric paddle-wheel structure type. It is an unusual example in that it contains two different carboxylate groups, viz. ferrocenecarboxylate and acetate. With three ferrocenecarboxylate groups and only one acetate group bridging the two Cu centres, a noncentrosymmetric molecular arrangement results.
ABSTRACT
In the title complex, poly[triaquabis(dimethylformamide)di-mu3-oxalato-mu2-oxalato-dilanthanum(III)], [La2(C2O4)3(C3H7NO)(H2O)3]n, both La ions are coordinated by nine O atoms, forming slightly distorted tricapped trigonal prisms. The two La ions, the terminal water O atom, and the O and N atoms of the dimethylformamide molecule reside on twofold rotation axes, giving the two La-centered coordination geometries twofold or pseudo-twofold symmetries. The two oxalate ligands, one of which rests on a center of inversion at the mid-point of the C-C bond, adopt different bridging modes, connecting with the La ions to form two types of lanthanide oxalate chains, i.e. anionic {[La(C2O4)2(DMF)(H2O)2]n-}(n) (DMF is dimethylformamide) and cationic zigzag {[La(C2O4)(H2O)]n+}n, respectively. Each zigzag cationic chain is linked to four adjacent anionic chains via the bridging oxalate anions, and each anionic chain connects with four zigzag cationic chains, constructing a three-dimensional neutral framework.
ABSTRACT
A complex with triple-stranded helices, {[Cu(mtz)]3(CuI)}n, was obtained under hydrothermal conditions. The complex possesses an unprecedented non-interpenetrated (12(3))(12(2).14)3 network, which represents the first example of the largest gon value of the smallest ring for the Archimedean net reported so far.
Subject(s)
Copper/chemistry , Models, Molecular , Spectrophotometry, Infrared , X-Ray DiffractionABSTRACT
In the presence of cobalt (nickel) acetate, a chiral tetrahedral intermediate ligand of (S)-(C5NH4)2C(OH)(C4NH7CO2H) was first formed from the nucleophilic addition of l-proline as a secondary amine to ketone (di-2-pyridyl ketone). Based on the ligand synthesized in situ, two chiral tetranuclear isomorphous complexes 1 and 2 with the formula {Na[M4L3(OAc)3](ClO4)(1.5)(H2O)(1.5)}(ClO4)(OH)(0.5).3H2O (M = Co, Ni) have been achieved. The Co4 cluster (1) behaves as a ferromagnet.
ABSTRACT
Three new zinc diphosphonates possessing bright purple fluorescence, high thermal stability, and an intriguing 3D pillared open framework with 1D 12-member ring channels encapsulating luminescent guest have been rationally designed and synthesized by introducing a luminescent guest as a structure-directing agent.
ABSTRACT
A 1D zinc coordination polymer with bright green fluorescence, [Zn(4,4'-bipy)(H2O)4][Zn(4,4'-bipy)(1.5)(L)(H2O)2]2(L).6H2O (L = 4,4'-bis(2-sulfonatostyryl)biphenyl), has been designed, hydrothermally synthesized and characterized; the interesting structure consists of three types of infinite chain: a neutral sandwich-like chain, ionic and cationic chains.
ABSTRACT
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.
