Photophysical Properties of 4′-(p-aminophenyl)-2,2′:6′,2′′-terpyridine

Spectral and photophysical investigations of 4′-(p-aminophenyl)-2,2′:6′,2′′-terpyridine (APT) have been performed in various solvents with different polarity and hydrogen-bonding ability.The emission spectra of APT are found to exhibit dual fluorescence in polar solvents, which attributes to the local excited and intramolecular charge transfer states, respectively. The two-state model is proven out for APT in polar solvent by the time-correlated single photon counting emission decay measurement. Interestingly, the linear relationships of different emission maxima and solvent polarity parameter are found for APT in protic and aprotic solvents, because of the hydrogen bond formation between APT and alcohols at the amino nitrogen N25. Furthermore, the effects of the complexation of the metal ion with tpy group of APT and the hydrogen bond formation between APT with methanol at the terpyridinenitrogen N4—N8—N14 are also presented. The appearance of new long-wave absorption and fluorescence bands indicates that a new ground state of the complexes is formed.     

Effect of solvent on the crystal structures of copper(II) complexes based on 4′-(4-methoxyphenyl)-2,2′:6′,2″-terpyridine and 4′-(3-chlorophenyl)-2,2′:6′,2″-terpyridine

Four homoleptic copper(II) complexes, [Cu(Meophtpy)₂](ClO₄)₂ (Meophtpy = 4′-(4-methoxylphenyl)- 2,2′:6′,2″-terpyridine) (I), [Cu(Meophtpy)₂](ClO₄)₂ · 2H₂O (II), [Cu₂(m-Clphtpy)₄](ClO₄)₄ (m-ClPhtpy = 4′-(3-chlorophenyl)-2,2′:6′,2″-terpyridine) (III), and [Cu₂(m-ClPhtpy)₄](ClO₄)₄ (IV) have been synthesized by hydrothermal methods and characterized by IR, elemental analysis and single crystal X-ray diffraction (CIF files CCDC nos. 963375 (I), 885457 (II), 963377 (III), and 963376 (IV)). Complex II is a polymorph of I and complex IV is a polymorph of III. All these complexes are obtained with 95% ethanol solution or 50% ethanol solution and the solvent control on the crystallization are obviously found. In all complexes, the face-to-face interactions between pyridyl rings or phenyl rings facilitate the construction of 3D network in the crystal in addition to hydrogen bonds. The fluorescence properties of these complexes have been investigated.     

4′-(2-Methylphenyl)-2,2′:6′,2″-terpyridine: coordination chemistry with Ni(II), Cu(II), Zn(II) and Ag(I)

The synthesis of 4′-(2-methylphenyl)-2,2′:6′,2″-terpyridine (L) has been improved. The coordination chemistry of the ligand was explored using Ni(II), Cu(II), Zn(II), and Ag(I) ions. X-ray crystallography, elemental analysis, NMR, and mass spectrometry were used to characterize the 13 new compounds that have been synthesized. Under different reaction conditions, Ni(II), Cu(II), and Zn(II) produced discrete complexes, sometimes containing more than one metal ion, while Ag(I) furnished a polymeric spiral complex in which the central pyridine nitrogen of each terpyridine ligand bridges two Ag(I) ions. Crystallographically characterized complexes are [Ni(L)₂]Cl₂, [Ni₂Cl₄(L)₂], [Ni(L)(OH₂)₃]Cl₂, [Ni(L)₂]Br₂, [Cu(L)(OH₂)(OSO₃)], [Cu₃Cl₆(L)₂], [Cu(L)(OH)(OH₂)₂]PF₆, [Cu(L)₂](OTf)₂, [Cu(L)(OAc)₂], [Zn(L)(OAc)₂], [Zn(L)Cl₂], [Zn(L)₂](NO₃)₂, [{Ag₂(μ-L)₂(μ-NO₃)}_n](NO₃)_n.     

Bis(2,2′bipyridine) ruthenium(II) complexes

A reinvestigation of the photolysis of [Ru(bipy)₃](NCSe)₂ in ethanol under dinitrogen has failed to give the previously reported [Ru(N₃)₂bipy₂] but, under appropriate conditions, may yield the complex [Ru(NCO)₂bipy₂].     

Studies on two cadmium(II) and two zinc(II) complexes of 4′-chloro-2,2′ : 6′,2″-terpyridine with 1 : 1 or 1 : 2 ratio of metal and ligand

The reaction between 4′-chloro-2,2′ : 6′,2″-terpyridine (tpyCl) with d¹⁰ transition-metal ions produced two cadmium(II) and two zinc(II) metal complexes, formulated as [Cd(tpyCl-κ ³ N,N′,N″)(NO₃-κ ² O,O′)(NO₃-κO)(H₂O-κO)] (1), [Cd(tpyCl-κ ³ N,N′,N″)₂](ClO₄)₂ (2), [Zn(tpyCl-κ ³ N,N′,N″)₂](ClO₄)₂ (3), and [Zn(tpyCl-κ ³ N,N′,N″)₂](BF₄)₂ (4). Supramolecular interactions include coordinative bonding, O–H ··· O, O–H ··· Cl, C–H ··· F, and C–H ··· Cl hydrogen bonding and π–π stacking, all of which play essential roles in forming different frameworks of 1–4.     

Nickel(II), cobalt(II), copper(II), and zinc(II) complexes with 4′-(4‴-benzo-15-crown-5)methyloxy-2,2′:6′,2″-terpyridine: Syntheses and vibrational spectra

Complexes of 4′-(4′″-benzo-15-crown-5)methyloxy-2,2′:6′,2″-terpyridine (L) with metal perchlorates and hexafluorophosphates, [ML₂](ClO₄)₂ · nH₂O and [ML₂](PF₆)₂ · nH₂O · mC₂H₅OH (M = Ni(II), Co(II), Zn(II), Cu(II); n = 0–3; m = 0–2), were synthesized. Their vibrational spectra were studied. The spectral criteria for ligand coordination through the terpyridinic nitrogen atoms were established. The conformational structure of the B15C5 macrocycles of a ligand molecule in the synthesized complexes was proposed. The complexes were studied by thermogravimetry.     

Kinetics and mechanism of oxidation of bis(2,2′,6′,2″-terpyridine) iron(II) by manganese(IV)

A study has been made on the oxidation of bis(2,2,6, 2-terpyridine)-iron(II), Fe(tpy) ₂ ²⁺ by manganese (IV) using stopped-flow spectrophotometry in H₂SO₄–H₃PO₄ mixtures. The reaction is first order in each the substrate and the oxidant. The rate of the reaction increases with hydrogen ion concentration. A plausible mechanism is proposed considering the protonated forms of manganese(IV) as reactive oxidizing species. The reaction obeys the rate law

A bifunctional 2,2′:6′,2″-terpyridine-based ligand for ratiometric Cu(II) sensing

Synthesis and characterization of the bifunctional sensor receptor ligand N-([2,2′:6′,2″-terpyridine]-4′-yl)methyl)-N-propylacrylamide (1) and the model ligand N-([2,2′:6′,2″-terpyridine]-4′-yl)methyl)-N-propylisobutyramide (2) are described. Ligand 1 is a receptor for Cu(II) that is copolymerizable with N-isopropylacrylamide giving a ratiometric sensor of weakly bound Cu(II) in environmental waters. Ligand 2 is a model for copolymerized 1 whereby the reactive acrylamide group is replaced by isobutyramide. Solution speciation of complexes of Cu(II) and Zn(II) with 2 were investigated spectroscopically and their solid-state structures were studied through single-crystal X-ray diffraction. Solution UV–vis and fluorescence studies show a preference of 2 toward Cu(II) over Na(I), Zn(II), Cu(II), Co(II), Mn(II), Ni(II), Cd(II), and Pb(II) in accord with the Irving–Williams series and other coordination principles. Solution speciation determined in a weakly coordinating aqueous-organic (60?:?40 DMF/H₂O) medium indicates 1?:?1 Cu(II):2 binding as desired in that formation of [Cu(2)₂]²⁺ would crosslink the polymer sensor. The crystal structures of [Cu(2)(NO₃)₂] and [Zn(2)(NO₃)₂]·MeOH·1/2Et₂O display distorted octahedral geometries where 2 coordinates meridionally and two nitrate groups occupy the remaining sites around the metal center.     

Selective formation of thecis isomer of the nitridotechnetium(V) complex with 2,2′:6′,2″-terpyridine

The reaction of [TcNCl₂(PPh₃)₂] with 2,2′:6′,2″-terpyridine producedcis-[TcNCl₂(terpy)] selectively. The resulting complexes were characterized by¹H NMR and IR spectroscopy. The geometries of thecis andtrans isomers were estimated by theoretical calculations following a density functional method. Thecis isomer is likely more stable than thetrans one with respect to thetrans influence of the nitrido ligand. Furthermore, the behavior of nitridotechnetium complexes in polar solvents was compared to Os-analogues.     

二-2,2′:6′,2″-三联吡啶-4′-(4-苯甲酰)-乙二胺的合成

二、三联吡啶作为螯合配体可以和过渡金属离子生成高度稳定的配合物,并具有有趣的物理性质。因此在过去的几十年里,二、三联吡啶金属配合物受到广泛而深入的研究。文章在前人的研究基础上获得了含官能化双(三联吡啶)单元结构的二-2,2′:6′,2″-三联吡啶-4′-(4-苯甲酰)-乙二胺配体,可以作为非共价聚合物的很有效的构建模块,合成有趣的金属超分子聚合物。     

Syntheses and characterization of two 1D Cu(II) coordination polymers with 2,2′:6′,2″-terpyridine ligand

The solution reactions of CuCl₂ with 2,2′:6′,2″-terpyridine (Terpy) and dicarboxylic acid (glutaric acid or suberic acid) afforded two 1D coordination polymers [Cu(Terpy)(C₅H₆O₄)] _n (I) and [Cu(Terpy)(C₈H₁₂O₄)] · 3H₂O (II) and their structures were characterized by IR, TG-DTA, and single-crystal X-ray diffraction. Crystallographic data for I: C₂₀H₁₆CuN₃O₄, M _r = 425.90, monoclinic, space group C2/c, a = 10.335(2), b = 21.193(4), c = 8.580(2) Å, β = 111.99(3)°, V = 1742.5(6) ų, Z = 4, ρ _c = 1.623 g/cm³, F(000) = 872, R = 0.0304 and wR = 0.0915; and those for II: C₂₃H₂₉CuN₃O₇, M _r = 523.03, triclinic, space group P \(\bar 1\), a = 8.362(2), b = 10.605(2), c = 14.617(3) Å, α = 73.26(3)°, β = 86.23(3)°, γ = 69.45(3)°, V = 1161.3(4) ų, Z = 2, ρ _c = 1.496 g/cm³, F(000) = 546, R = 0.0636 and wR = 0.1106. X-ray diffracion studies reveal that both complexes I and II feature 1D chain. The 1D polymer chains are connected by π-π-stacking interactions to generate 2D supramolecular layers.     

Copper(II), zinc(II) and mixed metal copper(II)-zinc(II) peroxocomplexes containing 2,2′,6′,2″-terpyridine

Summary Facile reaction of 2,2,6,2-terpyridine (L; terpy) with copper or zinc powders or their mixtures, in the presence of an excess of H₂O₂, leads to novel complexes [Cu(L)-(O₂ ^2–)]·3H₂O, [Zn(L)(O ₂ ^2– )]·H₂O and [Cu,Zn(L)₂(O ₂ ^2– )₂]· 4H₂O, respectively, which were isolated and characterized by elemental and micro- analysis, e.s.r., electronic, i.r. and thermogravimetric analysis in air and argon.     

A kinetic and mechanistic study of dinuclear Pt(II) 2,2′:6′,2″-terpyridine compounds bridged with polyethyleneglycol ether flexible linkers

A series of dinuclear Pt(II) complexes bridged with polyethyleneglycol ether of the type [ClPt(tpy)O(CH₂CH₂O)_n(tpy)PtCl]Cl₂ where n = 1 (Ptdteg), 2 (Ptdtdeg), 3 (Ptdtteg), 4 (Ptdttteg), and linker-free complex, (Ptdt) (where tpy = 2,2′:6′,2″-terpyridine), were synthesized and characterized to investigate the role of bridging polyethyleneglycol ether linker on the substitution reactivity of dinuclear Pt(II) complexes. Substitution reactions were studied using thiourea nucleophiles, viz. thiourea (TU), 1,3-dimethyl-2-thiourea (DMTU), 1,1,3,3-tetramethyl-2-thiourea (TMTU) under pseudo-first-order conditions as a function of concentration and temperature by conventional stopped-flow reaction analyzer. The reactions gave single exponential fits following the rate law k_obs = k₂[Nu]. Introduction of polyethyleneglycol ether linker decreases the electrophilicity of the platinum center and the whole complex. The results obtained indicate that the rate of substitution is controlled by both electronic and steric hindrance which increases with the length of the linker. Experimental results are supported by density functional theory calculations and structures obtained at B3LYP/LANL2DZ level. The order of the reactivity of the nucleophiles is TU > DMTU > TMTU. The magnitude and the size of the enthalpy of activation and entropy of activation support an associative mode of mechanism, where bond formation in the transition state is favored.     

Cadmium(II) complexes of 4′-tolyl-2,2′:6′,2′′-terpyridine: synthesis,structures, and antibacterial activities

A straightforward synthetic method has been developed to prepare cadmium(II) complexes of 4′-tolyl-2,2′:6′,2″-terpyridine (ttpy) in good yields. These complexes are formulated as {[Cd(ttpy)(NO₃)₂][Cd₂(ttpy)₂(NO₃)₄]} (1), [Cd₂(ttpy)₂(N₃)₄]0.5CH₃OH?·?0.125H₂O (2), and {[Cd(ttpy)(SCN)(CH₃COO)][Cd(ttpy)(SCN)₂]₂} (3). Intermolecular, intramolecular, hydrogen bonding and π–π stacking interactions were observed in the complexes, and are responsible for the arrangement of complexes in the crystal packing and play essential roles in forming different frameworks of 1–3. The antibacterial activities of the synthesized complexes were tested against three gram positive bacteria and three gram negative bacteria.     

2,2′:6′,2″-联三吡啶配体的合成

近年来,2,2′:6′,2″-联三吡啶作为典型的三齿有机杂环配体在超分子化学与材料化学领域得到广泛应用。通过取代基团对配体的结构修饰或改变金属离子的类型可以调控联三吡啶金属络合物的光物理和电化学性能,从而得到多种不同用途的功能化材料及超分子组装体。本文对单核联三吡啶配体近年来发展的典型合成方法加以阐述,并简单介绍联三吡啶配体在超分子化学中的应用。     

Synthesis of 4′-(4‴-benzo-15-crown-5)-methyloxy-2,2′:6′,2″-terpyridine (L) and the crystal structure of its complexes with cobalt(II) and zinc(II): [ML2](ClO4)2 · 3H2O

The synthesis of 4′-(4?-benzo-15-crown-5)-methyloxy-2,2′:6′,2″-terpyridine (L) and is complexes with cobalt(II) and zinc(II) [CoL₂](ClO₄)₂ · 3H₂O (I) and [ZnL₂](ClO₄)₂ · 3H₂O (II) was described. For L and its complexes, the parameters of electronic absorption spectra in acetonitrile were determined and ¹H NMR signals were assigned. The structures of I and II were determined by X-ray crystallography. Compounds I and II are isostructural and consist of complex cations [ML₂]²⁺ (M = Co, Zn), ClO ₄ ^? anions, and crystal water molecules. The M atoms are located in special positions on twofold axes. The M atoms are surrounded by six N atoms of the terpyridine moieties of two organic molecular ligands. The M-N distance for the N(2) atoms of the central rings of the terpyridine moieties in both structures is shorter than for the side rings. The coordination polyhedra of the M atoms can be described as severely distorted octahedra. The major distortion of the octahedra is that the N…N distances in a terpyridine moiety are considerably shorter than those between the atoms of different moieties. The maximal deviation of the terpyridine atoms from the mean-square planes through these atoms is observed for the C(2) atom: 0.103(3) and 0.106(4) Å in I and II, respectively. The Co(1) and Zn(1) atoms are at a distance of, respectively, 0.1682(14) and 0.1415(17) Å from the corresponding planes.     

Crystal structure of a hydroxo-bridged dimeric uranyl complex with a 2,2′:6′,2″-terpyridine ligand

A new dimeric compound [{UO₂(μ-OH)(terpy)}₂](ClO₄)₂·0.67CH₃CN, containing an uranyl cation and a tridentate 2,2′:6′,2″-terpyridine (terpy) ligand, is synthesized from an acetonitrile solution of uranyl perchlorate and terpy. The crystal structure of the compound is determined by single crystal X-ray diffraction. The crystal structure shows the formation of symmetric and asymmetric cationic hydroxo-bridged uranyl dimers. The uranium atoms adopt a distorted pentagonal bipyramidal configuration with a UO₄N₃ coordination environment formed by two uranyl O atoms, three N atoms from the terpy ligand, and two O atoms from the hydroxide anions.     

Synthesis of a new 2,2′：6′,2″-terpyridine derivative and its coordination property

A novel compound, （E）-4′-（4-（but-1-en-3-ynyl）phenyl）-2,2′：6′,2″-terpyridine 1 was synthesized from 4′-（4-bromomethylphenyl）-2,2P：6P,2PP-terpyridine phosphonium salt 2 and propargylaldehyde via Wittig reaction, and characterized by EI-MS and ^1H NMR as well as elemental analysis. The spectral changes of the compound in the presence of transition metal ions, such as Cu（I） or Zn（ID, are investigated.     

Synthesis,spectroscopy, thermal behavior,and X-ray crystal structure of two lead(II) complexes with 4′-(4-tolyl)-2,2′;6′,2″-terpyridine (ttpy)

Two new lead(II) complexes with 4′-(4-tolyl)-2,2′;6′,2″-terpyridine (ttpy), [Pb(ttpy)(µ-AcO)]₂(PF₆)₂ (1) and [Pb(ttpy)(µ-AcO)I]₂ (2), have been synthesized and characterized by CHN elemental analysis, ¹H NMR, ¹³C NMR, IR spectroscopy, and structurally analyzed by X-ray single-crystal diffraction. The thermal stability of these compounds has been studied by thermal gravimetric analysis and differential thermal analysis. Single crystal X-ray analysis shows that 1 and 2 are dimeric units with Pb–(µ-AcO)₂–Pb-type bridging, and the coordination number in 1 is six and in 2 is seven. The arrangement of donors suggests a gap in the coordination geometry around lead, possibly occupied by stereo-active lone pair of electrons on lead(II), so the coordination sphere is hemidirected. Furthermore, dimeric units are connected by a network of hydrogen bonds and π–π stacking as well. Electrochemical properties of free ligand and complexes have been investigated in the presence of tetrabutyl ammonium perchlorate as supporting electrolyte and by using a glassy carbon electrode. Both lead complexes show irreversible Pb(II) oxidation. Cyclic voltammetry indicates that these processes are diffusion-controlled. The data from electrochemical studies show that the total limiting current of each of the studied complexes corresponds to two-electron transfer.