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.     

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.     

Synthesis,molecular structure and electrochemistry of cobalt(II) complexes of 2,2′: 6′,2′′-terpyridine macrocycles

The macrocycle L, prepared by template condensation of bis-6,6′′-(α-methylhidrazino)-4′-phenyl-2,2′:6′′,2′-terpyridine with glyoxal, forms a stable crystalline complex of cobalt(II) [Co(L)(H₂O)₂][PF₆]₂ which has been used as a starting material to prepare, for electrochemical studies, a series of seven coordinate cobalt(II) complexes [Co(L)X₂][PF₆]₂ (X=pyridine, 4-cianopyridine, 4-aminopyridine, 4-dimethylaminopyridine, pirazine, imidazole, 1-methylimidazole, 2-methylimidazole, and trimethylphosphite). Cyclic voltammetry of the aquo complex in DMSO show one reversible reduction wave at −1.35 V versus Ag ∣ AgBF₄ reference electrode and controlled potential electrolysis in the presence of trimethylphosphite affords a diamagnetic species which has been assigned as a mononuclear d⁸ Co(I) species. The crystal and molecular structure of [Co(L)(imidazole)₂][PF₆]₂·Me₂CO shows the metal to be in a pentagonal-bipyramidal N₇ environment.     

Crystal Structures of Molecular Adducts between Uranyl Nitrate and 2,2′ : 6′,2′′-Terpyridine or 2,2′-Bipyridyl

Complexes of uranyl nitrate with aromatic molecular ligands : [UO₂Terpy(NO₃)₂] and (H₂Terpy)₂[UO₂(NO₃)₂(H₂O)₂](NO₃)₄ · 4H₂O (Terpy 2,2:6,2-terpyridine), (Hbipy)[UO₂(NO₃)₃] and [(UO₂)₂(Bipy)₂O₂(NO₃)₂] (Bipy—2,2-bipyridyl) and (HPy)₄[(UO₂)₂(NO₃)₄(OH)₂](NO₃)₂ (Py—pyridine) were characterized by X-ray diffraction analysis. In all these compounds, the U(VI) atom has the hexagonal bipyramidal environment. The U–O bond lengths in the UO₂ ²⁺ have close values. In the equatorial planes, the U–N bond lengths with the Bipy and Terpy ligands are identical, whereas the U–O bond lengths depend on the type of the ligand. The lengths of the equatorial bonds increase in the sequence U–N > U–O_nitr > U–O_hydr > U–O_perox. The geometric characteristics of the coordinated and solvate Terpy and Bipy molecules are different. The lengths of the N–O bonds in the NO₃ ^– groups depend on the participation of the O atom in the coordination of the central atom, the coordination mode, and the formation of hydrogen bonds.     

Dinuclear complexes of (2,2′-bipyridine)(2,2′:6′,2′'-terpyridine)-ruthenium(II) bonded through cyanide to pentaammineruthenium(II/III) groups

Summary New dinuclear complexes, containing a Ru(trpy)(bpy)²⁺ moiety (bpy = 2,2-bipyridine, trpy = 2,2:6,2'-terpyridine) bonded through cyanide to Ru(NH₃) _inf5 ^sup2+/3+ groups have been prepared and characterized by spectroscopic and electrochemical techniques. The formation of cyanide bridges is evident from the i.r. and u.v.-vis. spectra by appearance of v(CN) shifts and changes in _max with respect to the mononuclear parent complex [Ru(trpy)(bpy) (CN)]⁺. In the mixed-valence species Ru _infb ^supII —CN—Ru _infa ^supIII (Ru_b = Ru bonded to bpy, Ru_a = Ru bonded to NH₃), an intense metal-to-metal charge transfer transition is observed at _max = 700 nm in MeCN, with ovv _1/2 = 3.6 × 10³ cm^–1. From these spectral data and the difference in redox potentials between both metallic centres (determined by c.v. to be E _1/2 = 1.19 V), a value of k _th,r = 5 × 10⁵ s^-1 has been calculated for the rate of thermal intramolecular electron transfer of the reverse process: Ru _ina ^supII Ru _inb ^supIII . This low value suggests an inverted regime. The complexes studied are thus interesting as models for the design of energy conversion schemes.Presented in part at the XIX Latinoamerican Congress on Chemistry, Buenos Aires, Argentina, November 1990.     

Synthesis and crystal structure of bis[(μ-κO:κO′-acetato)(μ-κO:κ2O′-acetato)][(η5-Cp)tris(dimethylphosphito-P)cobalt-O,O′,O″]yttrium(III)

The [η⁵-CpCo{P(O)(OMe)₂}₃Y(O₂CCH₃)₂]₂, yttrium(III) complex has been synthesized by the stoichiometric mixture of YCl₃, NaL_OMe and NaAc in a 1:1:2 molecular ratio in dry THF solvent and we have determined the structure by X-ray diffraction. The molecule is a dimeric compound, which consists of one tripodal ligand (L_OMe=CpCo[P(O)(OMe)₂]₃) and two bridging acetato (Ac) ligands on each yttrium atom. The acetate ligands of this complex have two different coordination modes, which are μ-κO:κO′-acetato and μ-κO:κ²O′-acetato bound to each yttrium atom.     

[N,N′-(4-Methyl-4-azaheptane-1,7-diyl-κN)bis(4-methoxysalicylideniminato-κ4O,N,N′,O′)]cobalt(II) ethanol hemisolvate

The title compound, [Co(C₂₃H₂₉N₃O₄)]·0.5C₂H₆O or [Co^II{(4-MeO-sal)₂Medpt}]·0.5CH₃CH₂OH [(4-MeO-sal)₂Medpt is N,N′-(4-methyl-4-aza­heptane-1,7-diyl)­bis(4-methoxysalicyl­iden­iminate)], obtained through the reaction of H₂[(4-MeO-sal)₂Medpt] and Co(CH₃COO)₂ in refluxing ethanol under an atmosphere of ultrapure nitro­gen, has the usual pseudo-trigonal-bipyramidal coordination arrangement previously found for this class of (sal)₂Rdpt compounds. The O—Co—O bond angle [120.4 (1)°] is significantly smaller than the corresponding values previously found for most non-O₂-bound [Co^II{(sal)₂Medpt}]-type mol­ecules (observed range 126.9–138.6°), whereas the equatorial Co—N bond [2.185 (3) Å] is relatively long.     

Structural and Spectroscopic Studies of p-Nitrophenolato[2,2′,6′,2′′-Terpyridyl]-Copper(II) Perchlorate

The X-ray structure and low temperature electronic spectra of the title complex, 1, are presented, It crystallized in the monoclinic space group P2₁/c, with a = 10.387(1), b = 13.103(1), c = 16.153(2)Å, β = 98.59(1)°, V =2174(2) ų, Z =4 and refined to R(R _w) = 0.039(0.054) for 1980 reflections. The structure consists of monomeric Cu(lI) complexes having nearly square planar N₃(terpy)O(phenolate) equatorial ligation and weak axial ligation to a single perchlorate oxygen atom. An electronic absorption at 26,300 cm^-1 is consistent with phenolate oxygen → Cu(lI) LMCT while a second band at ca 14,300 cm^-1 is assigned to a ligand field transition.     

PVT properties of N,N,N′,N′-Tetraoctyl-3-oxapentanediamide (TODGA)

N,N,N??,N??-Tetraoctyl-3-oxapentanediamide (TODGA) is a versatile extractant for partitioning of fission products from highly active raffinate wastes. Its PVT properties are not available in literature. In this work, PVT properties of TODGA, estimated using group contribution method, are reported. A corresponding-states based equation as well as Wagner constants were also reported in the range of 273.15?K to critical temperature.     

CIRCULAR DICHROISM AND ELECTRONIC ABSORPTION OF RHODIUM(III) EDTA-TYPE COMPLEXES: Ethylenediamine-N,N′-diacetato-N,N′-di-3-propionatorhodate(III) and (S,S)-Ethylenediamine-N,N′-disuccinatorhodate(III) Ions

Abstract

Electronic absorption and CD spectra are reported for the sexidentate complexes, trans(O₅)-Rh(EDDDA)^?, trans(O₅ O₆)-Rh(EDDDA)^?, and trans(O₅)-Rh(S,S-EDDS)^? (EDDDA)=ethylenediamine-N,N′-di-3-propionate; S,S-EDDS=(S,S)-ethylenediamine-N,N′-disuccinate). Because of the sterospecific coordination of the S,S-EDDS ligand the absolute configuration of (+)_D-trans(O₅)-Rh(S,S-EDDS)^? is known to be Λ. By comparison of their CD spectra to that of the (+)_D isomer of trans(O₅)-Rh(S,S-EDDS)^?, the absolute configurations of the (?)_DEDDDA complexes are assigned tentatively.     

Molecular structure of 1′,3′,3′-trimethyl-6-trifluoromethylsulfonyl-spiro-(indoline-2,2′-benzo[b]pyran)

Photochromic 1, 3, 3 -trimethyl-6-trifluoromethylsulfonyl-spiro(indoline-2,2-ben-zo[b]pyran) (1) was studied by X-ray diffraction analysis. In compound1, the C_spiro-O bond (1.49(1) Å (average)), broken on photoexcitation, is the longest of all the indoline spiropyrans studied.Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1969–1971, November, 1994.     

Synthesis,Crystal Structure and Two-photon Absorption Properties of 4′-(N,N-di(4-hydroxymethyl phenyl) amino)phenyl-2,2′:6′,2'-terpyridine

A novel donor-acceptor(D-A) triphenylamino terpyridine derivative L was facilely synthesized and fully characterized, and its single crystals were obtained and determined by X-ray diffraction analysis. It crystallizes in triclinic, space group P1 with a = 11.760(5), b =12.516(5), c = 12.850(5) , α = 67.141(5), β = 65.284(5), γ = 75.876(5)o, Mr = 621.54, V = 1575.6(11) 3, Z = 2, Dc = 1.310 g/cm3, μ = 0.245 mm-1, F(000) = 648, the final R = 0.0671 and w R = 0.1869 for 11328 observed reflections with Ⅰ 2σ(Ⅰ). Linear and nonlinear optical properties of terpyridine derivative L were systematically investigated. The maximum two-photon cross-section of L was 382.5 GM(Goeppert-Mayer), measured by two-photon excited fluorescence(TPEF) method. This result demonstrates that the increase of intramolecular charge transfer(ICT) leads to enhanced two-photon absorption(2PA), which could be achieved by introducing additional electron-donor groups to the molecular framework.     

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.     

THE POLYMERIC COPPER COMPLEX 2,2′-BIPYRIDINE-N,N′-(μ-MALEATO-O,O′:O″)COPPER(II) DIHYDRATE

Abstract

Preparation and isolation of the polynuclear copper(II) complex, {[Cu(bipy)(maleato)] · 2H₂O} _n , was accomplished by reaction of an aqueous solution containing sodium maleate and an ethanolic solution of Cu(NO₃)₂·4H₂O and bipy. The crystal structure of the title complex was determined by single-crystal X-ray methods. The structure consists of one-dimensional infinite chains. The copper atom is five-coordinate and presents a square-pyramidal coordination sphere, which consists of the two imine N atoms of bipy and two terminal carboxylate O atoms of a maleate^2- ligand in the basal plane with Cu-N bond distances of 2.016(3) and 1.987(3) A and Cu-O distances of 1.909(2) and 1.947(2) Å, respectively. In the apical site an O atom of the maleate^2- ligand from an adjacent complex coordinates to copper (2.264(2) Å). The coordination fashion of the maleato ligand is also confirmed by the IR spectrum.     

Synthesis and characterization of chloro-bis(quinoline-2-carboxylato-κ2N,O)gallium(III)

The preparation and characterization of a new gallium(III) complex with quinoline-2-carboxylate, of formula [Ga(quin-2-c)₂Cl], are described. The crystal structure of the complex has been determined by X-ray diffraction, crystallizing in monoclinic space group P2₁/n with Ga(III) adopting a distorted tetragonal pyramid. Gallium(III) coordinates two quinoline-2-carboxylates and one chloride with a Cl,N₂,O₂ donor set. In the crystal the 2-D supramolecular structure is generated by weak intermolecular interactions, C–H?···?O, C–H?···?Cl, and C–H?···?π. The cytotoxicity assays against several human cancer cell lines (Du145, A549, MCF-7, A498, HT-29) and against mouse fibroblasts (BALB/3T3) revealed moderate antiproliferative activity of the complex.     

Hydrogen bonding in triamine copper(II) P,P′-Diphenylmethylenediphosphinate (pcp2−) hybrids. Syntheses and crystal structures of [Cu(pcp) (2,2′-dipyridylamine)(H2O)] · 2H2O and [Cu(pcp)(2,2′ : 6′,2′′terpyridine)] · 4H2O

Two hybrid materials [Cu(pcp)(dipyam)(H₂O)]?·?2H₂O (1) and [Cu(pcp)(terpy)]?·?4H₂O (2), have been prepared by reaction of copper(II) acetate monohydrate with P,P′ diphenylmethylenephosphinic acid (H₂pcp) and 2,2′ dipyridylamine (dipyam) or 2,2′?:?6′,2′′ terpyridine (terpy), and have been structurally characterized by X-ray analyses. Both structures have a three-dimensional architecture, created by a close network of hydrogen bonding interactions. The copper centers present approximate square-pyramidal coordination, surrounded by pcp, dipyam and one water molecule in 1, and by pcp and terpyridine in 2. In both complexes the pcp ligand chelates only one metal, so that the free phenylphosphinate oxygens remain available for hydrogen-bonding interactions with water molecules, present in coordinated and solvated forms in 1 and solely as the solvated form in 2.     

Preparation of organozirconium aromatic compounds in mixed aqueous-organic solvents: X-ray structures of [Cp2ZrCl(μ2-O′,O′′C-C6H5)], [(CpZr)3(μ2-O′,O′′C-C6H3Cl2)3(μ3-OH)(μ2-OH)3](Cl2C6H3COO)2, and [(CpZr)3(μ2-O′,O′′C-C6H4Cl)3(μ3-OH)(μ2-OH)3]Cl2·CH2Cl2

A new and facile method is presented for the synthesis of zirconocene carboxylate compounds, in which zirconocene dichloride (Cp₂ZrCl₂) is dissolved in 1 M aqueous HCl solution and the requisite ligand is dissolved in an organic solvent. Five such compounds [Cp₂ZrCl(μ₂-O′,O′′C-C₆H₅)] (1), [Cp₂ZrCl(μ₂-O′,O′′C-C₆H₃Cl₂)] (2), [Cp₂Zr(μ₂-O′,O′′C-C₆H₃(OH)Cl)₂] (3), [Cp₂Zr(μ₂-O′,O′′C-C₆H₃(OH)(NO₂))₂] (4), and [Cp₂Zr(μ₂-O′,O′′C-C₆H(OH)Cl₃)₂] (5) have been obtained by this method. The effect of pH on the stability of Cp₂ZrCl₂ in 1 M HCl solution has been investigated by UV/vis spectrophotometry and ¹H NMR spectrometry. The results showed that the aqueous Cp₂ZrCl₂ solutions became less stable with increasing pH, liberating cyclopentadiene. Accordingly, at higher pH (～7), two trinuclear zirconium monocyclopentadienyl compounds, [(CpZr)₃(μ₂-O′,O′′C-C₆H₃Cl₂)₃(μ₃-OH)(μ₂-OH)₃](Cl₂C₆H₃COO)₂ (6) and [(CpZr)₃(μ₂-O′,O′′C-C₆H₄Cl)₃(μ₃-OH)(μ₂-OH)₃]Cl₂·CH₂Cl₂ (7), were obtained. All compounds 1–7 have been characterized by FT-IR, ¹H NMR spectra and elemental analysis. In all of the compounds, the aromatic acid acts as a bidentate ligand in coordinating to the zirconium; both chelating and bridging modes are observed. X-ray crystallographic studies on 1, 6, and 7 have revealed that the geometries at zirconium are distorted octahedral in 6 and 7, and distorted trigonal-bipyramidal in 1.     

Reaction products distribution between square-planar gold(III) complexes and N,N,N′,N′-tetramethylthiuram disulfide. Crystal structure of bis(N,N-dimethyldithiocarbamato)gold(III) bromide dihydrate, [Au(Me2NCS2)2]Br·2H2O

Summary The reactions of N,N,N,N-tetramethylthiuram disulfide (tmtds) with gold(III) complexes of the [Au(L)X₃] type [L = N-methylimidazole (N-Melm), 2-methylbenzoxazole (2-MeBO) and 2,5-dimethylbenzoxazole (2,5-diMeBO), X = Cl, Br or I] are reported, and yielded two main types of product - [Au(Me₂dtc)X₂] (A) and [Au(Me₂dtc)₂]X (B) (Me₂dtc = N,N-dimethyldithiocarbamato anion). The ratio of the product yields (B/A) depends upon the nature of the ligand (L) and halogen (X). The ratio B/A for the reaction: [Au(L)Cl₃] + tmtds = A + B, increases in the sequence N-MeIm < 2- MeBO < 2,5-diMeBO, which correlates well with the level of cytotoxic activity exhibited by the [Au(L)Cl₃] complexes. A and B were characterized by their i.r., u.v-vis. and ¹-n.m.r. spectra. The magnetic measurements were also recorded. The data support a squareplanar geometry for gold(III) complexes with the Me₂dtc ligand bonded in a bidentate fashion; a conjecture has been verified crystallographically for [Au(Me₂NCS₂)₂]-Br·2H₂O. The X-ray analysis confirmed that the complex is composed of ionic units: [Au(Me₂dtc)₂] ⁺ and Br^– and H₂O molecules. The Au—S distances are markedly similar, falling in the 2.343(4)–2.350(3) A range.     

Kristallstruktur von N,N,N′,N′-Tetraisopropyl-p-phenylen-diammonium-dichlorid und-bis(tetrachloroaluminat)

Summary Protonation of the sterically overcrowded N,N,N,N-tetraisopropyl-p-phenylenediamine leads to a significant shortening of the C-N bond lengths of 7 pm as well as to a widening of the phenyl ipso-angle to 122°. All structural changes can be attributed to the twisted diisopropylammonium substituents and their electron acceptor properties.