Mingcai Yin

A noble-metal-free photocatalytic hydrogen production system based on cobalt(III) complex and eosin Y-sensitized TiO2

Although dye-sensitized TiO2 for photocatalytic H2 production have been investigated for more than 20 years, research on using low-cost transition metal complexes as catalysts for proton reduction on TiO2 is still relatively rare. In this paper, three cobalt complexes (CoL1–CoL3) were prepared and used as hydrogen evolution catalysts, and a noble-metal-free H2-evolving system was fabricated by using an organic dye, eosin Y (EY), as photosensitizer and triethylamine (TEA) as sacrificial agent. Under visible light irradiation, a turnover number of 90 (based on CoL2) was obtained for 2 wt% CoL2/TiO2 within 6 h in aqueous solution under the optimal conditions of 4 μmol EY, 5% TEA (v/v) and pH 11. In addition, much higher hydrogen production efficiency and stability were achieved for the heterogeneous system, in comparison with the homogeneous one.

Tripodal lipophilic ionophores: synthesis, cation binding and transport through liquid membranes

Abstract New C 3 -symmetric lipophilic tripodal ionophores, Et(CH 2 OCH 2 COR) 3 ; R=NMePh ( 1 ), R=NEtPh ( 2 ), R=piperidyl ( 3 ), have been prepared and their binding abilities for alkali and alkaline earth metal cations evaluated by extraction equilibrium and cation transport through bulk liquid membranes. Experiments show that these ionophores have considerable potential for transporting lithium, sodium and calcium ions relative to potassium and magnesium ions. The cation transport rates by ionophores 1 and 2 decrease in the order Li + >Na + >Ca 2+ >Ba 2+ >K + >Mg 2+ , and the selectivities of Li + /K + , Na + /K + and Ca 2+ /Mg 2+ are 6.47–7.24, 6.05–6.19 and 9.39–16.13, respectively. The extraction selectivity sequences of the ionophores 1 and 2 are in agreement with the descending order of the cation transport rate, and the complexation constants in chloroform phase were estimated.

Efficient photocatalytic hydrogen production over eosin Y-sensitized MoS2

MoS2 is considered as a promising alternative to noble metals for H2 evolution. In this work, a MoS2 catalyst was synthesized via a simple and feasible solvothermal process and characterized by XRD, SEM, TEM and XPS techniques. Though the thus-obtained MoS2 was stabilizing agent-free and composed of relatively large agglomerated particles, it shows superior hydrogen production performance under sensitization of eosin Y (EY), significantly different form earlier reports. Under optimized conditions, the hydrogen production rate was high, up to 35 mmol h−1 g−1, much higher than those of previous reports. We attribute this to its relatively high surface roughness and the small thin petal-like nanosheets constituting the MoS2, which result in more active sites for hydrogen evolution. Meanwhile, the obtained MoS2 shows excellent photostability with the H2-evolving activity remaining nearly unchanged after 4 cycles.

Two New Nickel(II) Complexes of (4-Amino-1,2,4-triazole-3,5-diyldithio)diacetic Acid: Syntheses, Crystal Structures and Characterizations

Two new complexes [Ni(phen)(H 2 O) 4 ] · (atda)(H 2 O) 5 (1) and [Ni 2 (4,4′ -bipy) 2 (H 2 O) 8 ] · (atda) 2 (2) (where H 2 atda = (4-amino-1,2,4-triazole-3,5-diyldithio)diacetic acid, phen = 1,10-phenanthroline, 4,4′ -bipy = 4,4′ -bipyridine) have been synthesized and characterized by elemental analysis, IR, UV, thermogravimetric analysis and X-ray diffraction technique. X-ray structural analyses reveal that the two complexes are both three-dimensional (3D) supramolecular structures and possess similar structural characters. The Ni(II) centers are both in distorted octahedral coordination environments, six-coordinated by four water molecules and two nitrogen atoms from a 1,10-phenanthroline molecule or two 4,4′ -bipyridine molecules. The atda 2 − ligands do not coordinate to the Ni(II) centers, but only exist as counter anions, forming hydrogen bonds with coordinated or uncoordinated water molecules. Various hydrogen-bonding interactions play an important role in the assembly of three-dimensional supramolecular architectures.

Syntheses, crystal structures, and catalytic activities of three new Cu(II) coordination polymers based on 2-(1H-1,2,4-triazole)-1-acetic acid

Three new coordination polymers, {[Cu(trza)(2,2′-bipy)(H2O)] · (ClO4)} n (1), {[Cu(trza)(2,2′-bipy)(H2O)] · (BF4)} n (2), and {[Cu(trza)(4,4′-bipy)] · (H2O) · (ClO4)} n (3) (Htrza = 2-(1H-1,2,4-triazole)-1-acetic acid), have been synthesized and characterized by single-crystal X-ray diffraction analysis. Both 1 and 2 exhibit 1-D chain structure while 3 displays 2-D layer structure. The catalytic activities of 1 and 3 in the green oxidative coupling of 2,6-dimethylphenol have been investigated.

Synthesis and characterization of a two-dimensional calcium complex with (1,3,4-thiadiazole-2,5-diyldithio)diacetic acid

A two-dimensional coordination polymer {[Ca2(tzda)2(H2O)4] · 3H2O} n , where H2tzda is a flexible carboxylate ligand (1,3,4-thiadiazole-2,5-diyldithio)diacetic acid, was synthesized and characterized by X-ray crystallography, IR, TGA and photoluminescence. The results show that there are two crystallographically independent Ca atoms in the structure, which are both seven-coordinate, but with different coordination environments. Two kinds of tzda2− ligands with identical coordination mode exist in {[Ca2(tzda)2(H2O)4] · 3H2O} n . The η 2-bridging O3 and O8 atoms link the Ca1 atoms into a 1-D chain, which are further connected by the tzda2− ligands forming a 2-D network. A series of hydrogen bonds link the 2-D network to form a 3-D architecture. The solid state luminescence behavior of {[Ca2(tzda)2(H2O)4] · 3H2O} n exhibits one intense emission band at 375 nm upon excitation at 315 nm which can be attributed to the intraligand emission.

Synthesis and crystal structure of a new zinc diphosphonate

A new zinc diphosphonate [NH3CH(CH3)CH2NH3]2Zn2(edbbp)2(HNO3)2·4H2O [eddbp = O3PCH(Ph)NH(CH2)2NHCH(Ph)PO3] was hydrothermally synthesized with Zn(NO3)2·6H2O, ethane-1,2-diamino-N,N′-bis(benzylphosphonic acid) (H4edbbp) and 1,2-propyldiamine. It consists of a centro-symmetric dimeric unit [Zn2(edbbp)2], in which each zinc ion adopts a distorted square-pyramidal coordination geometry. Hydrogen bonds formed between phosphonate groups and protonated 1,2-propyldiamine molecules link the dimeric units into one-dimensional chains. The doubly protonated 1,2-propyldiamine molecules serve not only as charge compensating counter ions, but also as bridging groups. Hydrogen-bonding interactions among the phosphonate oxygen atoms, water molecules, nitric acid molecules and protonated 1,2-propyldiamine result in the formation of a three-dimensional supramolecular network.

Synthesis, Crystal Structure, and Characterization of a New Zinc Complex with Flexible Ligand (4-Amino-1,2,4-triazole-3,5-diyldithio)diacetic Acid and 4,4′-Bipyridine

A new zinc coordination polymer, [Zn(atda)(4,4′-bipy)]n (H2atda = (4-amino-1,2,4-triazole-3,5-diyldithio)diacetic acid, 4,4′-bipy = 4,4′-bipyridine), was synthesized by rheological phase reaction method and characterized by elemental analysis, IR, UV and single-crystal X-ray diffraction. The results reveal that it possesses three-dimensional (3D) solid-state structure. The Zn(II) inos are interlinked by bridging of atda2 ligands and 1D [Zn(atda)]n double chains are constructed, which are further connected together by the coordination of 4,4′-bipy molecules and 2D double layered structure are generated. Hydrogen-bonding interaction exists between the layers, resulting in the formation of 3D supramolecular structure. In addition, thermal stability and fluorescent property were studied.

STUDIES ON THE SYNTHESIS AND CATION BINDING PROPERTIES OF TRIS(2-PYRIDYLAMINOCARBONYL-METHOXYMETHYL)PROPANE AND TRIS(2-PYRIDYLAMINOCARBONYLMETHYL)AMINE

ABSTRACT Two new tripod-like compounds, 1,1,1-tris(2-pyridylaminocarbonylmethoxymethyl)propane (1) and tris(2-pyridylaminocarbonylmethyl)amine (2), prepared by the reaction of 2-aminopyridine with 1,1,1-tris(ethoxycarbonylmethoxymethyl)propane or triethyl nitrilotriacetate, were evaluated as ionophores for alkali and alkaline earth metal ions by liquid membrane transport. Compound (1) showed relatively strong transport ability for calcium ions. But compound (2) showed low ability for transportation of all the tested ions because of the low lipophilicity. Complexes of compound (1) with copper(II), iron(III) and cobalt(II) ions and of compound (2) with copper(II), zinc(II) and cadmium(II) ions were also prepared, and were characterized by elemental analyses, IR spectra and thermal analysis.

Synthesis, Crystal Structure, and Characterization of Two New Zinc(II) Complexes With (4-Amino-1,2,4-triazole- 3,5-diyldithio)diacetic Acid and N-Containing Ligands

Two new complexes, [Zn(phen)(H2O)4]·(atda)·(H2O)5 (1) and [Zn(4,4′-bipy)2(H2O)4]·(atda) (2) (H2atda = (4-amino-1,2,4-triazole-3,5-diyldithio)diacetic acid, phen = 1,10-phenanthroline, 4,4′-bipy = 4,4′-bipyridine), have been synthesized and characterized. X-ray analyses revealed that in two complexes, the atda2− ligands act only as counteranions and three-dimensional (3D) supramolecular architectures are constructed via series of hydrogen-bonding interactions. Though the Zn(II) centers are both coordinated by four water molecules and two N atoms, the different arrangement style of coordinated water molecules in two complexes and the occurrence of lattice water molecules in complex 1 lead to different 3D structures. The IR and thermal analyses further confirmed the structural results.