Turn-on circularly polarized luminescent (CPL) molecular system realized by thermo-driven Newman–Kwart rearrangement reaction from CPL-silent O- to CPL-active S-thiocarbamate groups at peripheral position of 1,1′-binapthyl rings

Although chiral 1,1′-binaphthalene-2,2′-diyl-O,O-bis(N,N-dimethylthiocarbamate) (1) revealed no circularly polarized luminescence (CPL) signals, Newman–Kwart rearrangement of O-thiocarbamate groups at 1 yielded clear CPL signals from 1,1′-binaphthalene-2,2′-diyl-S,S-bis(N,N-dimethylthiocarbamate) (2), which acts as a CPL-gen molecule.     

Ferromagnetic interaction in iron(II)–bis-Schiff base complexes

The preparation and magnetic properties of three Fe(II)–bis-Schiff base complexes, [Fe₂(L1)2(4,4′-bpy)] · MeOH (1), [Fe(L2)(EtOH)] (2) and [Fe(L3)(MeOH)] (3) (L1 = N,N′-bis(2-hydroxy-1-naphthaldehyde)-1,2-phenylenediimine; L2 = N,N′-bis(salicylidene)-1,2-phenylenediamine; L3 = N,N′-bis(5-Cl-salicylidene)-1,2-phenylenediamine; 4,4′-bpy = 4,4′-bipyridine) are reported. X-ray single crystal structure analyses for 1–3 reveal that 1 shows a dinuclear Fe(II)–bis-Schiff base complex bridged by 4,4′-bpy, while 2 and 3 show mononuclear structures. Molecular packing of 2 shows a uniform one-dimensional chain structure through hydrogen bonds and Fe?π interaction and that of 3 indicates significant π–π interaction to form a dimmer structure. The χT–T plots of 1–3 show all ferromagnetic interaction at low temperature. The origin of the ferromagnetic interaction observed in 2 is tentatively ascribed to the dimer formation through Fe?π interaction at low temperature.     

Crystal Structure of Mononuclear Non-Heme Nikel(II) Octahedral Complex: [Ni(bqenH<Subscript>2</Subscript>)(bpy)](ClO<Subscript>4</Subscript>)<Subscript>2</Subscript>·0.125H<Subscript>2</Subscript>O

The crystal structure of a mononuclear Ni(II) complex [Ni(bqenH₂)(bpy)](ClO₄)₂·0.125H₂O 1 (where bqenH₂ is N,N′-bis(8-quinolyl)ethane-1,2-diamine, bpy = 2,2′-bipyridine) is reported here. The crystallographic data for 1 are as follows: monoclinic crystal system, P2_1/n space group, a = 17.3255(11), b = 10.6110(7), c = 34.328(2) Å, α = 90°, β = 93.9480(13)°, γ = 90°, V = 6295.8(7) ų, Z = 4, d_x = 1.541 mg/m³. The nickel(II) ion coordinates four N atoms of the tetradentate ligand bqenH₂ and two N atoms of the auxiliary bidentate 2,2′-bipyridine ligand, resulting in a slightly distorted NiN6 octahedron with two perchlorates serving as charge balancing counter anions. The overall structure of 1 is stabilized by the presence of water of crystallization in the crystal lattice. The crystal structure shows two symmetrically identical octahedral NiN6 units in its asymmetric unit. The extensive hydrogen bonding network resulting in a supramolecular architecture is observed due to the N–H?O, O–H?O, O–H?Cl, and N–H?Cl interactions.     

Synthesis of Schiff bases by aromatic amine condensation with 3,3′-bithiophenes-2,2′ and 4,4′-dicarbaldehydes

Reactions of aromatic amines with 3,3′-bithiophene-2,2′-dicarbaldehyde 1 and 3,3′-bithiophene-4,4′-dicarbaldehyde 2 gave the 2,2′-(N-(aryl)diimino)-3,3′-bithiophene 3 and 4,4′-(N-(aryl)diimino)-3,3′-bithiophene 4 in good yields. Orthophenylenediamine reacted with 1 and 2 to give dithieno[3,4-c;4′,3′-e]azepino[1,2-a]benzimidazole 5 and dithieno[2,3-c;3′,2′-e]azepino[1,2-a]benzimidazole 6. All these original products have been characterized by spectroscopic techniques and elemental analysis.     

Synthesis and transformations of bis(polychloroethylideneaminosulfonyl)- and bis(polychloroethylideneaminosulfonyl)-substituted derivatives of biphenyl, diphenyl oxide, and diphenylmethane

Reactions of N,N,N′,N′-tetrachlorobiphenyl-4,4′-disulfonamide, 4,4′-methylenebis(N,N-dichlorobenzenesulfonamide), and 4,4′-oxybis(N,N-dichlorobenzenesulfonamide) with 1,2-dichloroethylene and trichloroethylene open convenient synthetic approach to highly electrophilic bissulfony limines of dichloroacetic aldehyde and chloral: N,N′-bis(polychloroethylidene)biphenyl-4,4′-disulfonamides, 4,4′-methylenebis[N-(polychloroethylidene)benzenesulfonamides] and 4,4′-oxybis[N-(polychloroethylidene)benzenesulfonamides]. The synthetic opportunities of the bisazomethines obtained were demonstrated by examples of their reactions with water, methanol, chloroacetamide, and toluene where products of O-, N-nucleophiles addition to the azomethine bond and products of C-amidoalkylation of aromatic compound with imines were formed.     

Two New Cubane-Type Tetranuclear Compounds of Copper(II), Nickel(II) Derived from Reduced Schiff Base Ligand: Syntheses,Structures and Magnetic Properties

Two tetranuclear complexes, [M(H₃L)]₄·X (1, M = Cu, X = 4,4′-dpdo; 2, M = Ni, X = DMF, H₅L = 2-[(3,5-dibromo-2-hydroxybenzyl) amino]-2-(hydroxymethyl)propane-1,3-diol, 4,4′-dpdo is 4,4′-bipyridine-N,N′-dioxide, DMF = N,N′-dimethyl formamide), have been synthesized and characterized by elemental analysis, IR and X-ray single-crystal diffraction. Compound 1 features a centrosymmetric tetranuclear copper cluster which further constructed a 1D chain through a tetra-acceptor hydrogen bonds of 4,4′-dpdo molecule. Compound 2 having a P2₁ /n space group also exhibits a tetranuclear nickel cluster with a cubane topology in which the central Ni(II) ion and oxygen atoms from H₃L^2? occupy the alternate vertices of the cube. Magnetic properties of 1 and 2 in the 2–300 K have also been discussed. The tetranuclear cubanes cores display dominant ferromagnetic interactions.     

The copper(II) complexes with tetradentate Schiff base ligands: Synthesis, crystal structures, and computational studies

Mononuclear copper(II) Schiff base complexes, Cu(BrSal₂Pn) (I) and Cu(BrSal₂MePn) (II), where BrSal₂Pn = N,N′-bis(5-bromo-2-hydroxybenzylidene)propane-1,3-diamine and BrSal₂MePn = N,N′-bis(5-bromo-2-hydroxybenzylidene)-2,2-dimethylpropane-1,3-diamine, have been synthesized and characterized by elemental analyses and single-crystal X-ray diffraction. Also, the optimized geometries of them have been calculated using density functional theory method (B3LYP/6–31g). Obtained structural parameters are in agreement with the experimental data. The geometry around the copper atoms display a distorted square-planner structure by coordinating with two oxygen atoms from the phenols moieties and two nitrogen atoms from the imino groups of ligands and thus established three 6-membered rings.     

Synthesis of unsymmetrical phosphorus-containing macrocycles on the basis of hydroquinone, 4,4′-(propane-2,2-diyl)diphenol,and resorcinol

Bisphosphorylation of hydroquinone and 4,4′-(propane-2,2-diyl)diphenol was performed for the first time in ethyl acetate. The bisphosphorylated products were used in molecular assembly of unsymmetrical phosphorus(III)-containing macrocycles consisting of hydroquinone and 2,2-bis(p-hydroxyphenyl)propane or resorcinol fragments. The macrocyclic compound based on hydroquinone and 2,2-bis(p-hydroxyphenyl)-propane was subjected to oxidation and sulfurization to obtain the corresponding phosphorus(V) derivatives. Its biological activity was also studied.     

Studies on heat-resistant poly(metal phthalocyanine)-imide copolymers

Several new poly(metal phthalocyanine)imide copolymers have been prepared using 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BPTDA), metal(11) 4,4′,4″,4″′-phthalocyanine tetraamines (MPTA), p-phenylenediamine, 4,4′-methylenedianiline, and 9,9-bis(4-aminophenyl)-fluorene (BAF). The attractive feature of these polymers is their high thermooxidative and thermal stability. The polymer decomposition temperatures of all the imide copolymers are greater than 500°C in air and N atomspheres. Another noteworthy property is their high char yield: 60–78% at 800°C in a N₂ atmosphere. Variation of the metal phthalocyanine concentration has a remarkable effect on the thermal stability and degree of polymerization. The most preferred molar proportion of the reagents MPTA, diamine, and BTDA is 1.25:7.5:10. These polymers may be useful in the preparation of heat-resistant films and fibers.     

DFT study of the electronic and charge transfer properties of perfluoroarene–thiophene oligomers

The ground state structures of 5,5″-diperfluorophenyl-2,2′:5′,2″:5″,2‴-quaterthiophene (1), 5,5′-bis{1-[4-(thien-2-yl)perfluorophenyl]}-2,2′-dithiophene (2), 4,4′-bis[5-(2,2′-dithiophenyl)]-perfluorobiphenyl (3), 5,5″-diperfluorophenyl-2,2′:5′,2″-tertthiophene (4), 5,5′-diperfluorophenyl-2,2′-dihiophene (5), and 5,5-diperfluorophenylthiophene (6) have been optimized at the B3LYP/6-31G(d), B3LYP/6-31G(d,p), PBE0/6-31G(d), and PBE0/6-31G(d,p) level of theories. The B3LYP/6-31+G(d) and PBE0/6-31+G(d) level of theories have been applied to investigate the absorption spectra. The PBE0 functional is good to predict the C–S bond lengths while the C–F bond lengths are good envisaged with B3LYP functional. The increment of thiophene rings between two perfluoroarene rings leads to red shift in absorption spectra. The electron affinities are energetically destabilized while energetic stabilization of the radical-cation increases by decreasing the thiophene rings from four to one. The perfluoroarene rings leads to enhance the electron injection.     

The water-soluble indolium-based fluorescence probes for detection of the extreme acidity or extreme alkalinity

In this work, 3,3′-(((1E,1′E)-(H,12H-5,11-methanodibenzo[b,f][1,5]diazocine-2,8-diyl)bis(ethene-2,1-diyl))bis(1,1-dimethyl-1H-benzo[e]indole-3-ium-2,3-diyl))bis(propane-1-sulfonate) (1), 3,3’-(((1E,1′E)-(6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine-2,8-diyl)bis(ethene-2,1-diyl))bis(3,3-dimethyl-3H-indole-1-ium-2,1-diyl))bis(propane-1-sulfonate) (2), 2,2’-((1E,1′E)-(6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine-2,8-diyl)bis(ethene-2,1-diyl))bis(1,3,3-trimethyl-3H-indol-1-ium) iodide (3) and 2,2’-((1E,1′E)-(6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine-2,8-diyl)bis(ethene-2,1-diyl))bis(1,1,3-trimethyl-1H-benzo[e]indol-3-ium) iodide (4) were designed and synthesized by ethylene bridging of the N-substituted indolium salts and the Tröger’s Base (TB) framework. The probes exhibited a longer absorption and emission wavelength and the emission wavelength of them in dichloromethane (DCM) was more than 600 nm, performed a red fluorescence. All of the probes could work on the extreme acidic and the extreme alkaline environments and showed a good liner response in the working pH range. Especially, 2 and 4 were soluble in water and manifested a good pH sensing in a water system. Also, ¹H NMR analysis illustrated how these dyes worked as the pH-sensitive fluorescence probes. In addition, they performed excellent reversibility, high selectivity and good photostability.     

An approach to the synthesis of chemically modified bisazocalix[4]arenes and their extraction properties

Bisazocalix[4]arenes [N,N′-bis(5-azo-25,26,27-tribenzoyloxy-28-hydroxycalix[4]arene)benzene (1), N,N′-bis(5-azo-25,26,27-tribenzoyloxy-28-hydroxycalix[4]arene)biphenyl (2) and N,N′-bis(5-azo-25,26,27-tribenzoyloxy-28-hydroxycalix[4]arene)-2,2′-dinitro biphenyl (3)] have been synthesized from 25,26,27-tribenzoyloxy-28-hydroxycalix[4]arene by diazocoupling with the corresponding aromatic diamines (p-phenylenediamine, 4,4′-diamino biphenyl and 4,4′-diamino-2,2′-dinitrobiphenyl). Extraction studies of bisazocalix[4]arenes 1, 2, and 3 show no difference in their extraction behavior and selectivity, whereas azocalix[4]arenes are a poor extractant for heavy metal cations. The absorption spectra of the prepared bisazocalix[4]arenes are discussed, both the effect of varying pH and solvent upon the absorption ability of bisazocalix[4]arenes.     

Zinc(II), nickel(II) and cadmium(II) coordination polymers based on the ligand oxamide <Emphasis Type="Italic">N,N</Emphasis>-bis(4-phthalic acid): synthesis,structural characterization and magnetic properties

Three coordination polymers based on the new ligand oxamide N,N-bis(4-phthalic acid), namely [Zn(L)_0.5-(2,2′-bpy)] _n (1), [Ni₂(2,2′-bpy)₄(µ ²-Ox)]L·3H₂O (2) and [Cd(L)(1,10-phen)] (3) [L = oxamide N,N-bis(4-phthalic acid)], (2,2′-bpy = 2,2′-bipyridine), (1,10-phen = 1,10-phenanthroline), have been solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction: compound 1 is one-dimensional ladder-like coordination polymer, compound 2 exhibits a three-dimensional structure resulting in extensive hydrogen bonds built with the help of lattice water molecules, compound 3 also exhibits a three-dimensional supramolecular structure. All compounds were also characterized by elemental analysis, IR spectra and thermogravimetric analysis; furthermore, the magnetic measurements for 2 reveal antiferromagnetic coupling between the nickel(II) ions.     

Synthesis of 3-hetaryl-1,5,3-dithiazepanes and 3-hetaryl-1,5,3-dithiazocanes in the presence of catalysts based on transition metals

Efficient procedure was developed for 3-hetaryl-1,5,3-dithiazepanes and 3-hetaryl-1,5,3-dithiazocanes preparation from hetarylamines, N,N,N′,N′-tetramethylmethanediamine, and α,ω-alkanedithiols (ethane-1,2-dithiol, propane-1,3-dithiol), and also by the reaction of the latter with N,N-bis(methoxymethyl)hetarylamines in the presence of catalytic quantities of transition metals salts.     

Preparation and characterization of new poly(amide–imide) reinforced layer silicate nanocomposite containing N,N′-pyrromellitoyl-bis-l-phenyl acetic acid

Two new samples of poly(amide–imide)/montmorillonite reinforced nanocomposites containing N,N′-pyrromellitoyl-bis-l-phenyl acetic acid moiety in the main chain were synthesized by a convenient solution intercalation technique. Poly(amide–imide) (PAI) 3 as a source of polymer matrix was synthesized by the direct polycondensation reaction of N,N′-pyrromelitoyl-bis-l-phenyl acetic acid 1 with 4,4′-diamino diphenyl ether 2 in the presence of triphenyl phosphite (TPP), CaCl₂, pyridine and N-methyl-2-pyrrolidone (NMP). Morphology and structure of the resulting PAI-nanocomposite films 4a and 4b with 10% and 20% silicate particles were characterized by FTIR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nanocomposite films were investigated by using UV–vis spectroscopy, thermogravimetric analysis (TGA) and water uptake measurements.     

Synthesis, crystal structure and antibacterial activity of a group of mononuclear manganese(II) Schiff base complexes

Five mononuclear complexes of manganese(II) of a group of the general formula, [MnL(NCS)₂] where the Schiff base L = N,N′-bis[(pyridin-2-yl)ethylidene]ethane-1,2-diamine (L¹), (1); N,N′-bis[(pyridin-2-yl)benzylidene]ethane-1,2-diamine (L²), (2); N,N′-bis[(pyridin-2-yl)methylidene]propane-1,2-diamine (L³), (3); N,N′-bis[(pyridin-2-yl)ethylidene]propane-1,2-diamine (L⁴), (4) and N,N′-bis[(pyridin-2-yl)benzylidene]propane-1,2-diamine (L⁵), (5) have been prepared. The syntheses have been achieved by reacting manganese chloride with the corresponding tetradentate Schiff bases in presence of thiocyanate in the molar ratio of 1:1:2. The complexes have been characterized by IR spectroscopy, elemental analysis and other physicochemical studies, including crystal structure determination of 1, 2 and 4. Structural studies reveal that the complexes 1, 2 and 4 adopt highly distorted octahedral geometry. The antibacterial activity of all the complexes and their respective Schiff bases has been tested against Gram(+) and Gram(−) bacteria.     

Theoretical studies of the structures and spectroscopic properties of the photoelectrochemical cell ruthenium sensitizers, C101 and J13

A variety of heteroleptic ruthenium sensitizers have been engineered and synthesized because of their higher light-harvesting efficiency and lower charge-recombination possibility than the well known homoleptic N3 dye.As such,a great deal of attention has been focused on sensitizers with the general formula Ru(ancillary-ligand)(anchoring-ligand)(NCS) 2,among which important examples are Ru(4,4’-bis(5-hexylthiophen-2-yl)-2,2’-bipyridine)(4,4’-carboxylic acid-4’-2,2’-bipyridine)(NCS)2(C101) and Ru(N-(4-butoxyphenyl)-N-2-pyridinyl-2-pyridinamine)(4,4’-carboxylic acid-4’-2,2’-bipyridine)(NCS)2(J13).In order to simulate experimental conditions with different pH values,the photosensitizing processes of these sensitizers possessing different degrees of deprotonation (2H,1H to 0H) have been explored theoretically in this work.Their ground/excited state geometries,electronic structures and spectroscopic properties are first calculated using density functional theory (DFT) and time-dependent DFT (TDDFT).The absorption and emission spectra of all the complexes in acetonitrile solution are also predicted at the TDDFT (B3LYP) level.The calculated results show that the ancillary ligand contributes to the molecular orbital (MO) energy levels and absorption transitions.It is intriguing to observe that the introduction of a thiophene group into the ancillary ligand leads directly to the increased energy of the absorption transitions in the 380-450 nm region.The calculations reveal that although deprotonation destabilizes the overall frontier MOs of the chromophores,it tends to exert a greater influence on the unoccupied orbitals than on the occupied orbitals.Consequently,an obvious blue shift was observed for the absorptions and emissions in going from 2H,1H to 0H.Finally,the optimal degree of deprotonation for C101 and J13 has also been evaluated,which is expected to lead to further improvements in the performance of dye-sensitized solar cells (DSSCs) coated with such sensitizers.     

Reaction of thiourea with formaldehyde and simplest aliphatic diamines

N,N′-Bis(hydroxymethyl)thiourea reacted with propane-1,3-diamine at a molar ratio of 2 : 1 to give 5,5′-propane-1,3-diylbis(1,3,5-triazinane-2-thione), whereas 1,3,5,7,11,13,15,17-octaazatricyclo[15.3.1.1^7,11]-docosane-4,14-dithione was obtained in the reaction with equimolar amounts of the reactants. Tricyclic product was also formed in the three-component condensation of thiourea with formaldehyde and propane-1,3-diamine at a ratio of 1 : 3 : 1. The reactions of N,N′-bis(hydroxymethyl)thiourea with ethane-1,2-diamine (2 : 1) and of thiourea with formaldehyde and butane-1,4-diamine (1 : 2 : 1) afforded 5,5′-(ethane-1,2-diyl)bis(1,3,5-triazinane-2-thione) and 5,5′-(butane-1,4-diyl)bis(1,3,5-triazinane-2-thione), respectively.     

Design of postmetallocene catalytic systems of aryliminetype for olefins polymerization: XIII. Synthesis of tetradentate bis(2-hydroxy-1-naphthaldimine) ligands and their complexes with titanium(IV) dichloride

Reactions of 2-hydroxy-1-naphthaldehyde with 1,4-diaminobutane, 1,6-diaminohexane, 4,4′-methylenedianiline and its alkyl- and cycloalkyl-sybstituted derivatives, with 4,4′-sulfonyldianiline, 2,2′- and 4,4′-oxydianiline, 4,4′-(1,4-phenylenebisoxy)dianiline, 4,4′-[propane-2,2-diylbis(1,4-phenylenebisoxy)]dianiline, and p-terphenyl-4,4″-diamine afforded a series of the corresponding diimines that at treating with TiCl₂(OPr-i)₂ formed mono- and binuclear complexes of titanium(IV) dichloride with tetradentate ligands LTiCl₂ and L₂(TiCl₂)₂.     

Synthesis and characterization of optically active poly(amide-imide)s based on [N,N′-(4,4′-carbonyldiphtaloyl)-bis-lamino diacid]s and 1,5-bis(4-aminophenyl)penta-1,4-dien-3-one

Six dicarboxylic acids 3a-3f were synthesized by the reaction of 3,3’,4,4’-benzophenonetetracarboxylic dianhydride 1 with L-aminoacids 2a-2f in a solution of glacial acetic acid/pyridine(Py) at refluxing temperature.Then six new poly(amide-imide)s PAIs were synthesized from the direct polycondensation reaction of[N,N’-(4,4’- carbonyldiphtaloyl)-bis-L-amino diacid]s with 1,5-bis(4-aminophenyl)penta-1,4-dien-3-one(APPD).The polymerization reactions produced a series of new optically active PAIs with high yield and good inherent viscosity.Also these PAIs are optically active and soluble in various organic solvents.These resulting new polymers can be used in column chromatography for the separation of enantiomeric mixtures.The resulted polymers were fully characterized by means of FTIR and ~1H-NMR spectroscopy,elemental analyses,inherent viscosity measurements,solubility tests and thermogravimetric analysis(TGA).