Syntheses,crystal structures,and photoluminescence of two Cd(II) complexes with simple ligands

Two cadmium complexes, {[Cd₂(2,5-tda)₂(ip)₄]·4H₂O}_n (1) and {[Cd₂(4,4′-obb)₂(ip)₂·H₂O]·H₂O}_n (2) (2,5-tda?=?thiophene-2,5-dicarboxylic acid, 4,4′-obb?=?4,4′-oxybisbenzoic acid, ip?=?1H-imidazo[4,5-f][1, 10]-phenanthroline), were synthesized and characterized by IR, elemental analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. X-ray analysis revealed that 1 is a dinuclear complex with the 2,5-tda anion connecting two Cd ions in a μ₁-η¹:η⁰/μ₁-η¹:η⁰ coordination mode. Each dinuclear complex is further connected with neighboring complexes via hydrogen-bonding interactions. Compound 2 displays a 2-D layer structure with opened windows occupied by crystallographic water molecules. The layers are further packed via hydrogen-bonding interactions. Luminescent properties for 1 and 2 are also investigated in the solid state at room temperature.     

Syntheses,structures, and photoluminescence of three cadmium(II) coordination polymers with flexible bis(benzimidazole) ligands

Three cadmium(II) coordination polymers, [CdBr₂(L₁)] _n (1), [CdI₂(L₂)] _n (2), and Cd₂Br₄(L₃)₂ (3), where L₁?=?1,3-bis(5,6-dimethylbenzimidazole)propane, L₂?=?1,4-bis(5,6-dimethylbenzimidazole)butane, and L₃?=?1,6-bis(5,6-dimethylbenzimidazole)hexane, have been synthesized by hydrothermal methods and characterized by elemental analyses, IR spectra, TGA, PXRD, and X-ray crystallographic diffraction. Complex 1 contains a 1-D helical chain in which CdBr₂ units are linked by L₁. For 2, each CdI₂ is connected by two different conformations of L₂ to form a 1-D zigzag chain. For 3, each CdBr₂ is linked by L₃ bridges to afford a binuclear structure. These results indicate that the spacer length of the ligands play important roles in assembly of Cd(II) coordination polymers. Thermogravimetric analyses and solid-state luminescent properties of the complexes have also been investigated.     

Syntheses, crystal structures and properties of novel copper(II) complexes obtained by reactions of copper(II) sulfate pentahydrate with tripodal ligands

Three novel metal-organic frameworks (MOFs), [Cu(1)SO4].H2O (4), [Cu2(2)2(SO4)2].4H2O (5) and [Cu(3)(H2O)]SO4.5.5H2O (6), were obtained by hydrothermal reactions of CuSO4.5H2O with the corresponding ligands, which have different flexibility. The structures of the synthesized complexes were determined by single-crystal X-ray diffraction analyses. Complex 4 has a 2D network structure with two types of metallacycles. Complex 5 also has a 2D network structure in which each independent 2D sheet contains two sub-layers bridged by oxygen atoms of the sulfate anions. Complex 6 has a 2D puckered structure in which the sulfate anions serve as counter anions, which are different from those in complexes 4 (terminators) and 5 (bridges). The different structures of complexes 4, 5 and 6 indicate that the nature of organic ligands affected the structures of the assemblies greatly. The magnetic behavior of complex 5 and anion-exchange properties of complex 6 were investigated.     

Syntheses, structures and properties of silver(I) complexes with flexible 1,3,5-tris(pyridylmethoxyl)benzene ligands

Five new silver(I) complexes [Ag₂(L₂)₂](BF₄)₂·CH₃CN·CH₃OH (1), [Ag(L₂)(CF₃SO₃)] (2), [Ag(L₃)]ClO₄·CH₃OH (3), [Ag₂(L₃)₂](CF₃SO₃)₂·CH₃CN·CH₃OH·H₂O (4) and [Ag(L₃)]PF₆·2CH₃CN (5) [L₂=1,3,5-tris(2-pyridylmethoxyl)benzene, L₃=1,3,5-tris(3-pyridylmethoxyl)benzene] were synthesized and characterized by single crystal X-ray diffraction analyses. In complexes 1-5, ligands L₂ and L₃ show different conformations and act as three-connectors, while the Ag(I) atom serves as three-connecting node to result in the formation of 2D and 3D frameworks. Complexes 1 and 2 with different counteranions have similar 2D network structure with the same (4,8²) topology. Complex 3 has a 3D structure with (10,3)-a topology while complexes 4 and 5 have the same 2D (6,3) topological structure. The results showed that the structure of organic ligands and counteranions play subtle but important role in determining the structure of the complexes. In addition, the photoluminescence and anion-exchange properties of the complexes were investigated in the solid state at room temperature.     

Syntheses, crystal structures and properties of novel zinc(II) complexes obtained by reactions of zinc(II) malonate with flexible multidentate ligands

Complex [Zn₂(bimb)₂(mal)₂(H₂O)₂]·4H₂O (1) (mal=⁻OCOCH₂COO⁻) was obtained by reaction of bidentate ligand 4,4′-bis(imidazole-1-ylmethyl)biphenyl (bimb) with zinc(II) salt of malonate, while the reaction of the same metal salt with 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene (titmb) gives another novel complex [Zn₂(titmb)₂(mal)][mal]·12H₂O (2). The structures of these complexes were determined by X-ray crystallography. The results revealed that 1 is a cyclic dinuclear complex in which the malonate groups act as terminators and prevent further aggregation, while 2 is a 2D honeycomb network in which each independent 2D sheet contains two sub-layers bridged by the malonate groups and complex 2 also contains free malonate as a counteranion connected to the 2D layer by C-H?O hydrogen bonds. The entirely different structure and topology of complexes 1 and 2, on the one hand, indicates that the nature of organic ligands affected the structures of assemblies greatly, and on the other, reveals the versatility of the malonate which can act as a bridging and/or blocking ligand.     

Syntheses,crystal structures,and luminescent properties of lanthanide complexes with tripodal ligands bearing benzimidazole and pyridine groups

Two tripodal ligands, bis(2-benzimidazolylmethyl)(2-pyridylmethyl)amine (L(1)) and bis(2-pyridylmethyl)(2-benzimidazolylmethyl)amine (L(2)), were synthesized. With the third chromophoric ligand antipyrine (Antipy), three series of lanthanide(III) complexes were prepared: [LnL(1)(Antipy)(3)](ClO(4))(3) (series A), [LnL(1)(Antipy)Cl(H(2)O)(2)]Cl(2)(H(2)O)(2) (series B), and [LnL(2)(NO(3))(3)] (series C). The nitrate salt of the free ligand H(2)L(1).(NO(3))(2) and six complexes were structurally characterized: Pr(3+)A, Y(3+)A, Eu(3+)B, Eu(3+)C, Gd(3+)C and Tb(3+)C, in which the two A and three C complexes are isomorphous. Crystallographic studies showed that tripodal ligands L(1) and L(2) exhibited a tripodal coordination mode and formed 1:1 complexes with all lanthanide metal ions. The coordination numbers of the lanthanide metal ions for the A, B, and C complexes were 7, 8, and 10, respectively. Conductivity studies on the B and C complexes in methanol showed that, in the former, the coordinated Cl(-) dissociated to give 3:1 electrolytes and, in the latter, two coordinated NO(3)(-) ions dissociated to give 2:1 electrolytes. Detailed photophysical studies have been performed on the free ligands and their Gd(III), Eu(III), and Tb(III) complexes in several solvents. The results show a wide range in the emission properties of the complexes, which could be rationalized in terms of the coordination situation, the (3)LC level of the complexes, and the subtle variations in the steric properties of the ligands. In particular the Eu(3+)A and Tb(3+)A complexes, in which the central metal ions were wholly coordinated by chromophoric ligands of one L(1) and three antipyrine molecules, had relatively higher emission quantum yields than their corresponding B and C complexes.     

Syntheses, crystal structures, and magnetic properties of novel manganese(II) complexes with flexible tripodal ligand 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene

Two novel metal-organic frameworks (MOFs)--[Mn(titmb)(N3)2] x 1.5H2O (1) and [Mn3(titmb)2(C2O4)3(H2O)] x 10H2O (2)--were obtained by reactions of the flexible tripodal ligand 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene (titmb) with Mn(OAc)2 x 4H2O, together with NaN3 and K2C2O4, respectively. The structures of these MOFs were established by single-crystal X-ray diffraction analysis. The crystal data for 1 were as follows: monoclinic, C2/c, a = 20.956(13) A, b = 9.884(6) A, c = 24.318(14) A, beta = 95.87(5) degrees, Z = 8. The crystal data for 2 were as follows: triclinic, P1, a = 12.400(9) A, b = 16.827(12) A, c = 17.196(11) A, alpha = 66.35(5), beta = 95.87(5) degrees, gamma = 71.03(6), Z = 2. Complex 1 is a novel noninterpenetrating three-dimensional (3D) framework, in which the azide ligand connects Mn(II) atoms in an end-to-end (EE) mode to give [Mn-N-N-N-]n infinite one-dimensional (1D) chains, and complex 2 has a two-dimensional (2D) network structure in which the Mn(II) ions are linked by the oxalate anions to form 1D [Mn(C2O4)]n chains. Each titmb in these two complexes connects three metal atoms and serves as a three-connecting ligand. The magnetic properties of 1 and 2 were investigated. The results showed that the antiferromagnetic interactions occurred between the Mn(II) ions linked by the azide ligands in complex 1, and those linked by the oxalate anions and the carboxylate in syn-anti coordination mode in complex 2. The entirely different structures of complexes 1 and 2, on one hand, indicate that the azide and the oxalate ligands affected the structures of MOFs greatly, and on the other hand, reveals the potential applications of MOFs with the azide and oxalate ligands, which are efficient magnetic couplers.     

Syntheses, structures and catalytic activity of copper(II) complexes with hydroxyindanimine ligands

A series of new hydroxyindanimine ligands [ArNCC₂H₃(CH₃)C₆H₂(R)OH] (Ar = 2,6-i-Pr₂C₆H₃, R = H (HL¹), R = Cl (HL²), and R = Me (HL³)) were synthesized and characterized. Reaction of hydroxyindanimine with Cu(OAc)₂ · H₂O results in the formation of the mononuclear bis(hydroxyindaniminato)copper(II) complexes Cu[ArNCC₂H₃(CH₃)C₆H₂(R)O]₂ (Ar = 2,6-i-Pr₂C₆H₃, R = H (1), R = Cl (2), and R = Me (3)). The complex 2′ was obtained from the chlorobenzene solution of the complex 2, which has the same molecule formula with the complex 2 but it is a polymorph. All copper(II) complexes were characterized by their IR and elemental analyses. In addition, X-ray structure analyses were performed for complexes 1, 2, and 2′. After being activated with methylaluminoxane (MAO), complexes 1-3 can be used as catalysts for the vinyl polymerization of norbornene with moderate catalytic activities. Catalytic activities and the molecular weight of polynorbornene have been investigated for various reaction conditions.     

Syntheses,structures and catalytic properties of new mononuclear terpyridine-manganese(II) complexes with tetraphenylimido-diphosphinate and diphenylphosphinate ligands

Treatment of manganese(II) acetate tetrahydrate [Mn(CH3COO)₂·4H₂O] with one equivalent of 2,2′:6′,2′′-terpyridine (terpy) and two equivalents of potassium tetraphenylimido-diphosphinate K[N(Ph₂PO)₂] in methanol afforded a mononuclear manganese(II) complex, [(terpy)Mn{η¹-O-N(Ph₂PO)₂}₂(H₂O)] (1), with two terminal [N(Ph₂PO)₂]– ligands. Interaction of [Mn(CH₃COO)₂·4H₂O] with one equivalent of terpy in the presence of both K[N(Ph₂PO)₂] and Ph₂PO₂K in methanol gave a mononuclear manganese(II) complex [(terpy)Mn(η¹-O-O₂PPh₂){N(Ph₂PO)₂}] (2) with a chelated [N(Ph₂PO)₂]– ligand. Treatment of manganese(II) dichloride tetrahydrate [MnCl₂·4H₂O] with three equivalents of K[N(Ph₂PO)₂] in methanol resulted in isolation of a mononuclear manganese(III) complex [Mn{η¹-O-N(Ph₂PO)₂}-{N(Ph₂PO)₂}₂] (3) with one terminal and two chelated [N(Ph₂PO)₂]– ligands. Reaction of [Mn(CH₃COO)₂·4H₂O] with one equivalent of 4′-phenyl-[2,2′:6′,2′′]-terpyridine (4-Ph-terpy) and two equivalents of Ph₂PO₂K in methanol gave [(4-Ph-terpy)Mn(η¹-O-O₂PPh₂)₂(H₂O)] (4) with a labile water molecule. Complexes 1–4 have been spectroscopically characterized and their structures have been established by single-crystal X-ray diffraction. Catalytic behavior of 1 and 4 for sulfide oxidation was also investigated.     

Syntheses,crystal structures and magnetic properties of three new binuclear Ni(II) complexes derived from tripodal tetradentate (N4) ligands

Three new binuclear Ni(II) complexes [{Ni(L_22py)Cl}₂](ClO₄)₂ (1), [{Ni(L_23py)Cl}₂](ClO₄)₂ (2), and [{Ni(L_33py)Cl}₂](ClO₄)₂ (3), {L_22py = N-(2-pyridylmethyl)-N-(2-aminoethyl)-1,2-diaminoethane, L_23py = N-(2-pyridylmethyl)-N-(2-aminoethyl)-1,3-diaminopropane, L_33py = N-(2-pyridylmethyl)-N-(3-aminopropyl)-1,3-diaminopropane} have been synthesized. Single crystal X-ray structure analysis showed that in each complex two distorted octahedral Ni(II) ions are bridged asymmetrically by a pair of chloride anions. Variable temperature magnetic susceptibility measurements of 1 and 3 revealed dominant ferromagnetic exchange interactions.     

Syntheses,structures and electrochemical properties of ruthenium(II/III) complexes with tetradentate Schiff base ligands

Three unsymmetrical tetradentate Schiff base ligands, H₂salipn, H₂salipn-Br₄ and H₂salipn-Cl₂, have been synthesized from the typical condensation reactions of treating 1,2-diaminopropane with salicylaldehyde, 3,5-dibromosalicylaldehyde and 5-chlorosalicylaldehyde, respectively. Treatment of [RuCl₂(PPh₃)₃] with one equivalent of H₂salipn or H₂salipn-Br₄ in the presence of triethylamine in tetrahydrofuran (THF) afforded the corresponding ruthenium(III) complexes [Ru^IIICl(PPh₃)(salipn)] (1) and [Ru^IIICl(PPh₃)(salipn-Br₄)] (2). Interaction of [RuHCl(CO)(PPh₃)₃] with one equivalent of H₂salipn-Cl₂ or H₂salipn-Br₄ under the same conditions led to isolation of ruthenium(II) complexes [Ru^II(CO)(PPh₃)(salalipn-Cl₂)] (3) and [Ru^II(CO)(PPh₃)(salalipn-Br₄)] (4), respectively, in which one of the imine bonds was nucleophilically attacked by hydride to result in the formation of a mixed imine-amine ligand. The molecular structures of 1?1.5CH₂Cl₂, 2, 3?0.5CH₂Cl₂ and 4 have been determined by single-crystal X-ray crystallography. The electrochemical properties of 1–4 were also investigated. Their cyclic voltammograms displayed quasi-reversible Ru(IV)/Ru(III) and Ru(III)/Ru(II) couples with E^o ranging from 0.67 to 1.05 V and 0.74 to 0.80 V vs. Ag/AgCl (0.1 M), respectively.     

Synthesis, characterization, and structures of copper(II)-thiosulfate complexes incorporating tripodal tetraamine ligands

The reaction of [Cu(L)(H(2)O)](2+) with an excess of thiosulfate in aqueous solution produces a blue to green color change indicative of thiosulfate coordination to Cu(II) [L = tren, Bz(3)tren, Me(6)tren, and Me(3)tren; tren = tris(2-aminoethyl)amine, Bz(3)tren = tris(2-benzylaminoethyl)amine, Me(6)tren = tris(2,2-dimethylaminoethyl)amine, and Me(3)tren = tris(2-methylaminoethyl)amine]. In excess thiosulfate, only [Cu(Me(6)tren)(H(2)O)](2+) promotes the oxidation of thiosulfate to polythionates. Products suitable for single-crystal X-ray diffraction analyses were obtained for three thiosulfate complexes, namely, [Cu(tren)(S(2)O(3))].H(2)O, [Cu(Bz(3)tren)(S(2)O(3))].MeOH, and (H(3)Me(3)tren)[Cu(Me(3)tren)(S(2)O(3))](2)(ClO(4))(3). Isolation of [Cu(Me(6)tren)(S(2)O(3))] was prevented by its reactivity. In each complex, the copper(II) center is found in a trigonal bipyramidal (TBP) geometry consisting of four amine nitrogen atoms, with the bridgehead nitrogen in an axial position and an S-bound thiosulfate in the other axial site. Each structure exhibits H bonding (involving the amine ligand, thiosulfate, and solvent molecule, if present), forming either 2D sheets or 1D chains. The structure of [Cu(Me(3)tren)(MeCN)](ClO(4))(2) was also determined for comparison since no structures of mononuclear Cu(II)-Me(3)tren complexes have been reported. The thiosulfate binding constant was determined spectrophotometrically for each Cu(II)-amine complex. Three complexes yielded the highest values reported to date [K(f) = (1.82 +/- 0.09) x 10(3) M(-1) for tren, (4.30 +/- 0.21) x 10(4) M(-1) for Bz(3)tren, and (2.13 +/- 0.05) x 10(3) M(-1) for Me(3)tren], while for Me(6)tren, the binding constant was much smaller (40 +/- 10 M(-1)).     

Syntheses,crystal structures,and electrochemical properties of transition metal complexes with new tetrathiafulvalene-derivatized acetylacetonate ligands

Two new tetrathiafulvalene (TTF) derivatives of acetylacetone, namely, 3-[{6,7-benzo-2-(methylthio)-TTF-3-yl}-thio]-2,4-pentanedione (L₁) and 3-[{6,7-(ethylenedithio)-2-(methylthio)-TTF-3-yl}-thio]-2,4-pentanedione (L₂), have been synthesized. Four transition metal(II) complexes of these ligands, of general formulae [Zn(L₁)₂(THF)₂] and [M(L₂)₂(THF)₂] (M = Zn, Mn, and Ni), have been prepared and structurally characterized. The redox properties of both the ligands and their complexes were investigated by cyclic voltammetry. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Peng Zheng and Yun-Jun Guo contributed equally to this work.     

Four copper(II) complexes with potentially tetradentate tripodal ligands

The four title Cu^II compounds are chloro­[(2‐furyl­methyl)­bis(2‐pyridyl­methyl)­amine‐N,N′,N′′]copper(II) perchlorate, [CuCl(C₁₇H₁₇N₃O)]ClO₄, (I), chloro{2‐[bis(2‐pyridyl­methyl)­amino]­ethano­lato‐N,N′,N′′,O}­copper(II) hemi­[tetra­chloro­copper(II)], [CuCl(C₁₄H₁₇N₃O)][CuCl₄]_1/2, (II), chloro­[(2‐morpholino­ethyl)­bis(2‐pyridyl­methyl)­amine‐N,N′,N′′,N′′′]copper(II) perchlorate, [CuCl(C₁₈H₂₄N₄O)]ClO₄, (III), and chloro­[(2‐piperidinyl­ethyl)­bis(2‐pyridyl­methyl)­amine‐N,N′,N′′,N′′′]­copper(II) hexa­fluoro­phosphate, [CuCl(C₁₉H₂₆N₄)]­PF₆, (IV). They have tripodal potentially tetradentate ligands. In (I), the O atom of the furan moiety weakly coordinates to the Cu atom at a distance of 2.750 (3) Å.     

Syntheses,crystal structures,and catalytic properties of dioxomolybdenum(VI) complexes with hydrazone ligands

Two new dioxomolybdenum(VI) complexes, [MoO₂L¹(CH₃OH)] (1) and [MoO₂L²(H₂O)] (2), where L¹ and L² are dianionic form of N′-(2-hydroxy-3-methoxybenzylidene)-4methoxybenzohydrazide and N′-(2-hydroxy-3methoxybenzylidene)-2-hydroxybenzohydrazide, respectively, have been synthesized and structurally characterized by spectroscopic methods and single-crystal X-ray determination. The complexes are mononuclear molybdenum(VI) compounds. Mo in each complex is octahedral. The difference in the substituent groups in the benzohydrazides leads to coordination of different solvent molecules. Crystals of the complexes are stabilized by hydrogen bonds. The complexes are effective catalysts for sulfoxidation.     

Syntheses,structures and properties of four second-sphere coordination complexes via metal halide anion and naphthalene-based ligand

Second-sphere coordination refers to any intermolecular interactions with the ligands directly bound to the primary coordination sphere of a metal ion. Four supramolecular complexes, 0.5[L·2H]²⁺·0.5[MCl₄]^2?·[CH₃OH]·0.5[CH₂Cl₂] (M = Co, crystal 1; M = Mn, crystal 2), 0.5[L·2H]²⁺·0.5[ZnBr₄]^2?·[CH₃OH]·0.5[CH₂Cl₂] (crystal 3), and 0.5[L·2H]²⁺·0.5[Cu₂Br₄]^2?·H₂O (crystal 4), based on naphthalene-based ligand N,N,N′,N′-tetra-p-methylnaphthyl-ethanediamine (L), have been synthesized. X-ray analysis reveals that 1–3 are isostructural, in which the methanol molecules are bridges, connecting the protonated L and metal chloride anions via N–H?O and O–H?Cl (Br) interactions to construct the host framework, and forming X-shaped cavity accessible for the inclusion of weakly polar guest molecules of dichloromethane. Dichloromethane is connected with the host framework through van der Waals forces. In 4, a dinuclear anion [Cu₂Br₄]^2? is connected with the ligand through N–H?Br interactions, in which the water molecules are accommodated between chains formed by the ligand and [Cu₂Br₄]^2?. Structure stability, thermal analysis, and photoluminescent properties were studied for 1–4.     

Syntheses,structures, and properties of seven-coordinate calcium(II) and five-coordinate lead(II) complexes with 1-D structures

Two new 1-D heterometallic coordination polymers (CPs), {[Ca(NiL)(H₂O)₄]?·?3H₂O} _n (1) and {[Pb(NiL)(H₂O)₂]?·?3H₂O)} _n (2), have been prepared by reactions of CaCl₂ and NiL and Pb(NO₃)₂ and NiL in CH₂Cl₂–H₂O. H₂L denotes dimethyl 5,6,7,8,15,16-hexahydro-6,7-dioxodibenzo-9,10-benzo-[1,4,8,11]tetraazacyclotetradecine-13,18-dicarboxylate. Single-crystal X-ray diffraction studies show that the coordination geometries around Ni(II) in both 1 and 2 are similar distorted N₄ square planar. All Ni–N bonds are short. Complex 1 has 1-D zigzag chain, while 2 shows 1-D “head-to-tail” structure. In crystals 1 and 2, 1-D CP chains were parallel-packed and 3-D supramolecular networks were formed via weak hydrogen bond interactions between aqua ligands and lattice water. The effects of water on the assemblies of the two CPs are discussed. Coordinated water plays an important role on the assembly procedure.     

Syntheses,structures and magnetic properties of three cobalt(II) coordination polymers based on flexible itaconic acid ligands

Transition Metal Chemistry - Three Co(II) coordination polymers, namely [Co(ia)(bpe)0.5(H2O)]n (1), {[Co(ia)(bib)(H2O)]·H2O}n (2) and {[Co(ia)(btmb)(H2O)]·H2O}n (3)...