Adducts of lanthanide β-diketonates with 2,4,6-tri(2-pyridyl)-1,3,5-triazine: Synthesis,structural characterization,and photoluminescence studies

Adducts of lanthanide β-diketonates of the general formula LnL₃(TPTZ) were synthesized and structurally characterized by single crystal X-ray diffraction [Ln = Eu³⁺, Tb³⁺, Er³⁺; L is the conjugate base of dibenzoylmethane (DBM), 1-benzoylacetone (BA), thenoyltrifluoroacetone (TTA), or 4,4,4-trifluoro-1-phenyl-1,3-butanedione (BTFA); TPTZ = 2,4,6-tri(2-pyridyl)-1,3,5-triazine, a rigid Lewis base with a large π system]. The lanthanide ion in each of these complexes is nonacoordinate with six β-diketonate oxygen atoms and three TPTZ nitrogen atoms, forming a coordination polyhedron best describable as a monocapped square antiprism. Characteristic red, green, and near infrared luminescence was observed for the Eu³⁺, Tb³⁺, and Er³⁺ complexes, respectively. All complexes showed significantly enhanced luminescence quantum yields when compared with the corresponding aqua analogues, with one of the Eu³⁺ complexes displaying a quantum yield of 69.7% in chloroform.     

Synthesis,structural, photophysical and thermal properties of some praseodymium(III) complexes

Some carboxylato-bridged praseodymium(III) complexes (1–5) having tp [hydrotris(pyrazol-1-yl)borate] and sodium p-X-benzoate (where X =?H, F, Cl, NO₂) have been synthesized and characterized by different techniques including X-ray crystallography. The X-ray studies demonstrated that 1, 3 and 5 crystallized in triclinic space group P 1 with cell dimensions a =?11.761(13) Å, b =?12.536(13) Å, c =?17.726(19) Å for 1, a =?9.309(8) Å, b =?12.667(11) Å, c =?14.421(12) Å for 3, a =?11.5688(9) Å, b =?12.0055(9) Å, c =?12.3005(10) Å for 5. In 1–4 the coordination number of praseodymium is seven, whereas in 5 it is eight. IR suggested that the benzoate groups in 1–5 are bidentate bridging. The photophysical properties of these complexes have been studied in solution at room temperature. Thermogravimetric analysis showed that these complexes undergo complete decomposition with formation of praseodymium oxide.     

Luminescent nine-coordinate lanthanide complexes derived from fluorinated β-diketone and 2,4,6-tris(2-pyridyl)-1,3,5-triazine

The synthesis, photoluminescence, 4f–4f absorptions, and NMR studies of nine-coordinate lanthanide(III) complexes, [Ln(tfaa)₃(tptz)] (Ln?=?La, Nd, Sm, and Eu; tfaa is the anion of 1,1,1-trifluoro-2,4-pantanedione; and tptz?=?2,4,6-tris(2-pyridyl)-1,3,5-triazine), are reported. These complexes are synthesized in a single pot by in situ method and thoroughly characterized. The β-diketone and tptz chemical shifts, in the cases of paramagnetic complexes, are in the opposite directions. The lanthanide-induced shifts are dipolar in nature. The luminescence and 4f–4f absorptions are analyzed and discussed. The samarium and europium complexes emit strong pink and red luminescences due to ⁴G_5/2?→?⁶H_j (j?=?5/2, 7/2, 9/2) and ⁵D₀?→?⁷F_j (j?=?0–4) transitions, respectively. The ⁴G_5/2→⁶H_7/2 (607?nm) emission transition of Sm(III) has no Stark components and indicates a higher local symmetry around Sm(III). The very strong hypersensitive ⁵D₀?→?⁷F₂ transition of Eu reflects a highly polarizable chemical environment around Eu(III). The absorption spectra of the neodymium complex are investigated and analyzed.     

Ruthenium, osmium and rhodium complexes of polypyridyl ligands: Metal-promoted activities, stereochemical aspects and electrochemical properties

This article presents a brief overview of the reactions of2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) in presence of rhodium(III), ruthenium(II) and osmium(II) under various experimental conditions. Under certain experimental conditions tptz exhibits metal-assisted hydrolysis/hydroxylation at the triazine ring. However, synthetic methods have also been developed to prepare complexes with intact tptz. Molecular structures of some of the complexes, especially stereoisomers of the hydroxylated products, are established by single crystal X-ray studies. A critical analysis of all data suggests that the electron-withdrawing effect of the metal ion (L→Mσ donation) is the predominant factor, rather than angular strain, that is responsible for metal-promoted reactivities. Electrochemical properties of all of these complexes have been investigated, Rh(III) complexes are excellent catalysts for electrocatalytic reduction of CO₂, and dinuclear Ru(II) and Os(II) complexes exhibit strong electronic communication between the metal centres.     

Syntheses and crystal structures of copper(II) complexes derived from 2,4,6-tris(2-pyridyl)-1,3,5-triazine

Treatment of freshly precipitated Cu(OH)₂?·?xH₂O and 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) with oxalic and malonic acids in methanol-water at room temperature gave [Cu(tptz)(C₂O₄)(H₂O)]?·?4H₂O (1) and [Cu(pma)(C₃H₂O₄)(H₂O)]?·?H₂O (2) (pma?=?2-aminocarbonylpyridine), respectively. Reaction in the absence of any acid resulted in [Cu(bpca)(tca)]?·?2H₂O (3) (bpca?=?bis(2-pyridylcarbonyl)amide anion; tca?=?2-pyridinecarboxylate anion). Complex 1 consists of [Cu(tptz)(C₂O₄)(H₂O)] and lattice H₂O molecules; the tridentate tptz ligand, bidentate oxalate dianion and an aqua ligand are bound to Cu with distorted octahedral geometry. Complex 2 is composed of [Cu(pma)(C₃H₂O₄)(H₂O)] and lattice H₂O molecules; the bidentate 2-aminocarbonylpyridine ligand, a bidentate malonate dianion and an aqua ligand are coordinated to Cu with a slightly distorted square pyramidal geometry. Complex 3 consists of [Cu(bpca)(tca)] and lattice H₂O molecules. Square pyramidally coordinated Cu atoms are surrounded by tridentate bpca with nitrogen donor atoms and a bidentate 2-pyridinecarboxylate anion.     

Copper(II)-assisted thorough hydrolysis of 2,4,6-tris(2-pyridyl)1,3,5-triazine (tptz). Crystal structures of bis(2-pyridylcarboxylato)-copper(II) dihydrate and bis(2-pyridylcarbonyl)-amido-2,4,6-tris(2-pyridyl)-1,3,5-triazine-copper(II) dicyanamide heptahydrate

2,4,6-Tris(2-pyridyl)-1,3,5-triazine (tptz) undergoes hydrolysis in the presence of copper(II) acetate affording bis(2-pyridylcarbonyl)amido-copper(II) and free 2-pyridylcarboxylic anion. Two compounds of formulas [Cu(NC₅H₄COO)₂]·2H₂O (1) and [Cu(NC₅H₄CO)₂N(tptz)](N(CN)₂)·7H₂O (2), where NC₅H₄COO^? and (NC₅H₄CO)₂N^? are 2-pyridylcarboxylate and bis(2-pyridylcarbonyl)amido-anion, respectively, were obtained from methanol/ethanol solution of tptz with copper acetate; they were characterized by element analysis and single crystal X-ray diffraction method. Single crystal XRD analysis shows that in complex 1 coordination number around Cu atom is 4 with distorted square-planar coordination geometry and in complex 2 coordination number around Cu atom is 6 with distorted octahedral geometry. Crystal data for 1: a = 5.1359(10) Å, b = 7.6471(15) Å, c = 9.2303(18) Å, α = 74.90(3)°, β = 84.36(3)°, γ = 71.37(3)°, space group P1, crystal system triclinic, Z = 1, V = 331.6(1) ų, d _calc = 1.721 g/cm³. Crystallographic data for 2: space group C2/c, crystal system monoclinic, a = 23.976(5) Å, b = 15.465(3) Å, c = 18.649(4) Å, β = 92.66(3)°, V = 6907(2) ų, d _calc = 1.0448 g/cm³, Z = 4.     

2,4,6-三萘基-1,3,5-三嗪的合成与光谱行为

本文通过Suzuki偶联反应高效合成了两种三萘基三嗪化合物,即2,4,6-三(1-萘基)-1,3,5-三嗪(T1NT)和2,4,6-三(2-萘基)-1,3,5-三嗪(T2NT). 考察了介质的极性、温度以及THF-H₂O二元溶剂体系中的溶解性等因素对它们吸收和发射光谱行为的影响.研究发现, 由于T1NT比T2NT具有更好的分子平面性,其激发态下分子内电荷转移的程度较大,导致其在溶液中吸收光谱、发射光谱比T2NT呈现显著红移.冻结态下,分子平面性较差的T2NT显示出较短波长的发光.     

Transition Metal Ion-Directed Coordination Polymers with Mixed Ligands: Synthesis,Structure, and Photocatalytic Activity for Hydrogen Production and Rhodamine B Degradation

Three mixed-ligand transition metal coordination polymers with the formula of {[Cu^I₂Cu^II(tpt)₂(L)] · 15H₂O}_n ( 1 ) and {[M₂(H₂O)₅(tpt)(L)] · 6H₂O}_n [M = Ni for 2 and Co for 3 ; tpt = 2,4,6-tris(4-pyridyl)-1,3,5-triazine and L = 3,3'-disulfonyl-4,4'-biphenyldicarboxylate] were hydrothermally synthesized by varying the cheap paramagnetic metal ions and used as photocatalysts for hydrogen evolution from water splitting and rhodamine B (RhB) degradation. Single-crystal structural determinations reveal that 1 is a robust pillared-layer framework with unusual 72-membered {Cu₆(tpt)₆} macrocycle-based layers supported by tetratopic L^4– connectors. Both 2 and 3 are isostructural (4 4) sheets with octahedral Ni^II and Co^II ions extended by ditopic L^4– and tpt linkages, in which the third pyridyl group of tpt is capped by pentahydrated metal ions. Due to the narrowed bandgap and good charge transport of the mixed-valence Cu^I/II centers, 1 exhibits improved dual-functional catalytic activities than 2 and 3 with the visible-light-driven hydrogen evolution rate and RhB degradation efficiency up to 588 μmol · g^–1 · h^–1 and 72 % after 180-minute irradiation. These interesting results indicate the importance of the metal ions and the dimensionality of the coordination polymers on the activity of the non-Pt coordination polymer photocatalytic systems.     

Group 13 Metal Halide Based Coordination Polymers of Al,Ga, In and 2,4,6-Tri(4-pyridyl)-1,3,5-triazine

Four isotypic one-dimensional coordination polymers (CP) were synthesized using the group 13 metal halides AlBr₃, GaCl₃, GaBr₃, and InI₃ and the tridentate ligand 2,4,6-tri(4-pyridyl)-1,3,5-triazine (tpt) serving as bidentate linker. The neutral one-dimensional CPs ¹_∞[AlBr₃(tpt)], ¹_∞[GaCl₃(tpt)], ¹_∞[GaBr₃(tpt)], and ¹_∞[InI₃(tpt)] are constituted by zigzag-shaped chains in the crystal structure, in which one coordination site of the tpt ligand remains uncoordinated. All CPs were characterized by SCXRD, PXRD, simultaneous DTA/TG, elemental-analysis and IR spectroscopy. Furthermore, three complexes of the composition [(AlBr₃)₃(tpt)], [(GaCl₃)₃(tpt)], and [(GaBr₃)₃(tpt)] were structurally characterized by SCXRD, being preliminary and side products of the formation of the coordination polymers.     

Mononuclear and binuclear sandwich copper(II) complexes with poly(pyrazolyl)borate ligands: syntheses, structures and properties

A series of Cu(II) complexes Cu(2)[micro-pz](2)[HB(pz)(3)](2) (1), Cu[H(2)B(pz)(2)](2) (2), Cu[HB(pz)(3)](2) (3), Cu[HB(pz(Me2))(3)](2) (4), Cu[B(pz)(4)](2) (5) (pz=pyrazole), have been synthesized and characterized by elemental analysis, IR, UV-vis, X-ray diffraction, thermal analysis and theoretical analysis. The IR spectra give the Cu-N vibration modes at 322, 366, 344, 387, and 380 cm(-1) in complexes 1-5, respectively. The UV spectra show all the complexes have same UV absorption at 232 nm; there is another band at 332 nm for complexes 1, 2 and 4, while for complexes 3 and 5, the bands are at 272 and 308 nm, respectively. Complex 1 has a binuclear structure in which two pyrazole ligands bridge two Cu-Tp units. In 2-5, the Cu(II) centers are coordinated with dihydrobis(pyrazolyl)borate (Bp), hydrotris(pyrazolyl)borate (Tp), hydrotris(3,5-Me2pyrazolyl)borate (Tp'), tetrakis(pyrazolyl)borate (Tkp) respectively to form a mononuclear structure. The results of thermal analysis for complexes 1-5 are discussed too.     

Chromatographic preconcentration of copper in environmental and biological samples using 2,4,6-tri(2-pyridyl)-1,3,5-triazine-tetraphenylborate-naphthalene adsorbent

A method was established for the determination of trace amounts of copper using chromatographic preconcentration of copper(I) with 2,4,6-tri(2-pyridyl)-1,3,5-triazine and tetraphenylborate. Copper is quantitatively adsorbed on this adsorbent in the pH range 1.8–10.5 and at flow-rates of 0.2–10 ml/min. The solid mass consisting of copper complex along with naphthalene is dissolved from the column with 5 ml of dimethylformamide. A calibration curve is obeyed over the concentration range 0.2–10.0 g of copper in 5 ml of dimethylformamide. Eight replicate determinations of 3 g of copper gave a mean absorbance of 0.185 with a relative standard deviation of 1.4%. The characteristic concentration for 1% absorption is 0.0143 g/ml (0.103 gmg/ml for direct AAS in aqueous medium). The interference of various ion and salts has been studied and the proposed method has been employed to the determination of copper in biological and water samples.     

A 3D Supramolecular Pd（Ⅱ） Complex via Hydrogen-bonding and Weak M…M Interactions

The reaction of 2,4,6-tris（2-pyridyl）-1,3,5-triazine （tptz） and K2PdCl4 in THF/H2O （10：1） results in the hydrolysis of tptz to bis（2-pyridylcarbonyl）amide anion （bpca）, and affords complex Pd（bpca）Cl 1, which is the first example of Pd（Ⅱ）-promoted hydrolysis of ligands. Crystal data for 1： orthorhombic, space group Pbcn, a = 12.0136（17）, b = 14.180（2）, c = 6.9747（11）A, V= 1188.2（3） A3, Z = 4, Mr = 368.06, Dc = 2.058 g/cm3, F（000） = 720,μ = 1.786 mm^-1, λ（MoKα） = 0.71073 A, T= 293（2） K, 2θmax = 54.9°, GOOF = 1.085, the final R= 0.0647 and wR = 0.1051 for 1234 observed reflections with I 〉 2σ（I） （refinement on F2）. Complex 1 is connected through hydrogen bonding to give a 2D network. And weak Pd...Pd interactions are also found between adjacent molecules with the distance of 3.6074（5） A, so the complex is further extended into a 3D supramolecular structure. Thermal gravity analysis （TGA） shows that 1 exhibits high thermal stability below 310℃. X-ray powder diffraction （XRD） and UV/Vis spectrum of 1 are also discussed.     

Trisubstituted 1,3,5-Triazines. 6. Synthesis of 2,4,6-Tris(acetonyl)-1,3,5-triazine

Acylation of 2,4,6-tris(tert-butoxycarbonylmethyl)-1,3,5-triazine with acetic anhydride in the presence of lithium hydride with subsequent removal of the tert-butoxycarbonyl groups with trifluoroacetic acid leads to 2,4,6-tris(acetonyl)-1,3,5-triazine, the cyclic analog of -cyanoacetone. The special spectral features of this compound compared with triazines obtained previously are discussed.     

Ni(II) and Co(III) complexes of 5-methyl-1,3,4-thiadiazole-2-thiol: syntheses,spectral, structural,thermal analysis,and DFT calculation

Two new complexes, [Ni(en)₂(mtt)₂] (1) and [Co(en)₂(mtt)₂](mtt) (2) (Hmtt = 5-methyl-1,3,4-thiadiazole-2-thiol and en = ethylenediamine), have been synthesized and characterized by various physicochemical techniques. Complexes 1 and 2 crystallize in monoclinic and orthorhombic system with space groups P 21/n and P 21 21 21, respectively. The molecular structures of 1 and 2 show that the metal ions are six-coordinate bonded through four equatorial nitrogens of two en and two axial nitrogens of mtt ligands. The crystal structures of the complexes reveal that mtt is present in thione form and bound to the metal ion through the thiadiazole nitrogen. The crystal structures of the complexes are stabilized by various intermolecular hydrogen bonding providing supramolecular architecture. Complex 2 is also stabilized by weak π···π interactions occurring between two thiadiazole rings. The bioefficacies of the ligand and complexes have been examined against the growth of bacteria to evaluate their antimicrobial potential. The biological results suggest that 2 is more active than the ligand and 1 against the tested bacteria. The geometries of the ligand and the complexes have been optimized by the DFT method and the results are compared with the X-ray diffraction data. The Co(III) complex exhibits an irreversible Co(III)/Co(II) process while the Ni(II) complex displays quasi-reversible Ni(II)/Ni(III) redox processes with large peak separation as compared to that expected for a one electron process which is thought to be coupled with some chemical reaction.     

Synthesis and structural characterization of novel zinc(II) and cadmium(II) complexes with pyridine-phosphine chalcogenide ligands

New pyridine-phosphine chalcogenide ligands, tris[2-(2-pyridyl)ethyl]phosphine sulfide 1a and tris[2-(2-pyridyl)ethyl]phosphine selenide 1b, react with zinc(II) and cadmium(II) chlorides in EtOH at room temperature to afford complexes of compositions 2ZnCl₂·2L (2, L = 1a) and 3CdCl₂·2L (3a,b, L = 1a,b) in high yields. The solid-state structure of complexes 2, 3 has been proved by X-ray analysis data. Complex 2 is a centrosymmetric dimer, where two atoms of zinc are bonded by two bridging pyridine-phosphine sulfide ligands through N atoms. Complexes 3a,b exist as polymeric chains with each bridging ligand acting as a chelate N,S- or N,Se-donor to one cadmium(II) center and as a pyridine N-donor to the next cadmium(II) center.     

Synthesis,structures, and properties of bis(4,6-disubstituted 1,3,5-triazin-2-yl) ethers

Reactions of (4,6-disubstituted 1,3,5-triazin-2-yl)trimethylammonium chlorides with glycine sodium salt in the presence of Et₃N afforded bis(triazin-2-yl) ethers instead of the expected triazinylaminoacetic acids. The structures of the resulting compounds were established by the independent synthesis, spectroscopic data, and X-ray diffraction analysis.     

Nucleophilic Substitution Reactions of 2,4,6-Tris(trinitromethyl)-1,3,5-triazine. 3. Reaction of 2,4,6-Tris(trinitromethyl)-1,3,5-triazine with Azides and Hydrazine

As a result of nucleophilic substitution of the trinitromethyl groups in 2,4,6-tris(trinitromethyl)-1,3,5-triazine, the corresponding monoazido and diazido derivatives have been synthesized. The reaction of the starting triazine with hydrazine acetate in the presence of trifluoroacetic acid leads to 1-acetyl-2,2-bis[4,6-bis(trinitromethyl)-1,3,5-triazin-2-yl]hydrazine.     

Synthesis of linear and V-shaped oligo(phenylene ethynylene) derivatives: geometric effects on photophysical properties

<正>A series of linear and V-shaped oligo(phenylene ethynylene) derivatives 1-3 were synthesized through sequent Sonogashira coupling and propargyl alcohol deprotection reaction in high yields.The alkoxy chains(i.e.,n-hexyloxy groups) were introduced to assure good solubility of compounds 1-3 in common solvents.The photophysical properties of 1-3 in solution depend strongly on the geometries of these compounds.     

1D & 2D Supramolecular assemblies dominated by crystal structure of Pb(II) oxoanion ( and ) complexes with 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine (PDPT)

The two lead(II) complexes, [Pb(PDPT)(NO₃)₂] _n and [Pb(PDPT)₂(ClO₄)₂EtOH]·CH₃OH, PDPT?=?3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine, have been synthesized and characterized. 1D & 2D supramolecular assemblies of these compounds in the solid state are discussed via covalent and noncovalent donor?···?acceptor interactions.