Synthesis,characterization and crystal structure of one Mn(II) complex with 4,4′-bisimidazolylbiphenyl and 4,4′-sulfonyldibenzoic acid

One new title compound [Mn₃(BIBP)(sdb)(NO₂⁻)₂(H₂O)₂]_n·2DMF (1) (BIBP = 4,4′-bisimidazolylbiphenyl, sdb = 4,4′-sulfonyldibenzoic acid) has been synthesized under hydrothermal condition. The title compound was characterized by IR spectra, thermal analysis, single crystal and powder X-ray diffraction. Magnetic susceptibility measurements indicate that compound 1 exhibits antiferromagnetic coupling interaction.     

Synthesis,characterization and properties of polyimides from 3,3′,4,4′-benzophenonetetracarboxylic dianhydride and imidazole-blocked 2,5-bis[(n-alkyloxy)methyl]-1,4-benzenediisocyanates

Summary By the solution condensation of 3,3,4,4-benzophenonetetracarboxylic dianhydride (BTDA) with imidazole-blocked 2,5-bis[(n-alkyloxy)methyl]-1,4-benzenediisocyanates (C_m-BDIs) a series of aromatic polyimides (C_m-BP-PIs) having flexible (n-alkyoxy)methyl (-CH₂O-n-C_mH_2m+1, m=4, 6, 8) side chains were prepared and characterized by IR- and ¹H-NMR spectroscopy and their properties were measured and discussed in respect to the effects of side chains. Inherent viscosities of the polymers were in the 0.23–0.34 dL/g range. All the polymers were highly soluble in N,N-dimethylpropyleneura(DMPU) and C₆- and C₈-BP-PIs even in CHCl₃ at room temperature. UV-VIS spectra showed that the -electrons are delocalized along the main chain. TGA studies showed a two-step pyrolysis behavior and in DSC Tg's of C₄-, C₆- and C₈-BP-PIs were determined to be 184, 135 and 127 °C, respectively. Wide-angle X-ray diffractometry for as-polymerized samples revealed a quite low crystallinity with only loosely developed layered structure.     

Low-dielectric-constant aromatic homopolyimide and copolyimide derived from pyromellitic dianhydride, 4,4′-oxydianiline, 2,2-bis[4-(4-aminephenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene,or 1,3-bis(4-aminophenoxy)benzene

Low-dielectric-constant aromatics, homopolyimide and copolyimide, were introduced. Homopolyimides were prepared by pyromellitic dianhydride (PMDA) as an anhydride monomer and 4,4′-oxydianiline (ODA), 2,2-bis[4-(4-aminephenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, or 1,3-bis(4-aminophenoxy)benzene as an amine monomer. The copolyimides were prepared with PMDA as an anhydride monomer, ODA as an amine monomer with the addition of 2,2-bis[4-(4-aminephenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, or 1,3-bis(4-aminophenoxy)benzene as another amine monomer. The polyimides were well characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, thermomechanical analysis, dielectric measurements, and tensile testing. The homopolyimide and copolyimides showed lower dielectric constants than the homopolyimide formed by ODA and PMDA. The results also indicate that the interchain distance, the quantities of phenyl ether, and the position of the substitute are factors that not only affected the thermal performance of polyimide by improving the molecular flexibility but also reduced the dielectric constant of polyimide by increasing the free volume of the molecular chain and decreasing the polarization points per unit volume. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47405.     

Synthesis,characterization, and structure-property relationships of aromatic polyimides containing 4,4′-diaminotriphenylmethane

This work reports two series of structurally different aromatic polyimides based on 4,4´-diaminodiphenylmethane (DPM) and 4,4´-diaminotriphenylmethane (TPM) and three commercial dianhydrides. All TPM-based polyimides formed membranes due to their high molecular weight (inherent viscosities ~0.93–1.14 dl/g), they exhibited high thermal stability (5 %: 490–544 °C), glass transition temperatures between 269 and 293 °C, and reasonable mechanical properties. The incorporation of pendant phenyl moieties in the TPM-based polyimides has a strong effect producing an improvement in solubility, thermal stability, density and gas permeability coefficient in comparison with DPM-based polyimides. The most interesting polyimide TPM-6FDA, containing phenyl and trifluoromethyl as bulky pendant groups, showed higher gas permeability coefficient for CO₂ (23.73 Barrer) and the best ideal selectivity to the gas pair CO₂/CH₄ (α = 28.93).     

Synthesis,characterization and crystal structure of (cis-P,P′-diphenyl-1,4-diphospha-cyclohexane)molybdenum(0)tetracarbonyl

The preparation of the novel (cis-P,P′-diphenyl-1,4-diphospha-cyclohexane)molybdenum(0)tetracarbonyl complex is described. The spectral data and X-ray structure of the title complex are reported. The results of the crystallographic work show a distorted octahedral complex around the metal center, the first of its kind reported for the P,P′-diphenyl-1,4-diphospha-cyclohexane ligand.     

Synthesis and crystal structure of 1,4-diaminobutyl-N,N′-bis(cyanoborane): the first substituted-borane adduct of putrescine

The reaction of 1,4-diaminobutane (putrescine) with two molar equivalents of trimethylaminecyanoborane in anhydrous diethyl ether, produced an unprecedented cyanoborane species, 1,4-diaminobutyl-N,N^′-bis(cyanoborane) (1), in 78% yield, via a Lewis-base exchange reaction. The crystal structure showed the title compound (1) to be a zwitterionic species in which the two nitrogen atoms of a putrescine unit are coordinated to two cyanoborane units.     

Synthesis and properties of polysiloxane containing N,N′-bis(diphenylsilyl)tetraphenylcyclodisilazane

A new kind of polysiloxane containing N,N′-bis(diphenylsilyl)tetraphenylcyclodisilazane was prepared by the anionic polymerization with a “seed solution” as initiator. The synthesis of monomers N,N′-bis(hydroxydiphenylsilyl)tetraphenylcyclodisilazane (BHPTPC), N,N′-bis(chlorodiphenylsilyl)tetraphenylcyclodisilazane (BCPTPC), and 1,3-dichloro-1,1,3,3-tetraphenyldisilazane (DCTPS) are all reported in this study. The synthesized polysiloxane containing N,N′-bis(diphenylsilyl)tetraphenylcyclodisilazane was characterized by ¹H–NMR, ²⁹Si–NMR, gel permeation chromatography (GPC), and intrinsic viscosity. The thermal stability of the polysiloxane was studied by isothermal gravimetric analysis (IGA). The results demonstrated that the synthesized polysiloxane containing N,N′-bis(diphenylsilyl)tetraphenylcyclodisilazane had excellent thermal stability. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 929–933, 2001     

Synthesis and properties of poly(ester imide) copolymers from 3,3′,4,4′-biphenyltetracarboxylic dianhydride, 2,2′-bis(trifluoromethyl)benzidine,and 4-aminophenyl-4′-aminobenzoate

A series of poly(ester imide) (PEsI) copolymers were synthesized using 3,3′,4,4′-biphenyltetracarboxylic dianhydride (4,4′-BPDA), 2,2′-bis(trifluoromethyl)benzidine (TFMB), and 4-aminophenyl-4′-aminobenzoate (APAB) as the monomers. Wide-angle x-ray diffraction results revealed that the average interchain distances of these polymers ranged from 4.6 to 5.7 Å, increasing with the increase of TFMB contents. PEsI-0.3 and PEsI-0.4 exhibited a glass transition temperature (T_g) of 445 and 455°C, respectively, while no distinctive T_g was observed for the PEsI copolymers when the APAB content was >50 mol%. The coefficients of thermal expansion (CTE) of these PEsI copolymers ranged from 3.8 to 24.2 ppm K⁻¹, increasing with the increase of TFMB contents. The PEsI copolymers exhibited a modulus of 5.7–7.8 GPa, a tensile strength of 282–332 MPa, and an elongation-at-break of 10.2%–23.3%. Furthermore, these copolymers exhibited a dielectric constant of 2.53–2.76, and a low dissipation factor (D_f) of 0.0026–0.0032 at 10 GHz in dry state. Because of their excellent combined properties, these PEsI copolymers are promising candidates as dielectric substrate materials for the applications in next generation flexible printed circuit boards operating at high frequencies.     

Tricarbonyl rhenium complex of 2,2′-bis(4,5-dimethylimidazole) — Synthesis,spectroscopic characterization,X-ray structure and DFT calculations

The paper presents a combined experimental and computational study of the tricarbonyl rhenium(I) complex incorporating 2,2′-bis(4,5-dimethylimidazole) (tmbiimH₂). The complex has been studied by IR, UV–Vis spectroscopy and X-ray crystallography. The electronic structure of [Re(CO)₃(tmbiimH₂)Cl] has been calculated with the density functional theory (DFT) method, and the electronic spectrum of the complex was investigated at the TDDFT level employing B3LYP functional in combination with LANL2DZ.     

Synthesis,characterization, optical and electrical properties of thermally stable polyazomethines derived from 4,4′-oxydianiline

Three soluble, thermally stable azomethine polymers were synthesized by the oxidative polycondensation of azomethine bisphenols using NaOCl as an oxidant in aqueous alkaline medium. The azomethine bisphenol monomers, 4,4′-oxybis[N-(2-hydroxy-3-methoxybenzilidine)aniline], 4,4′-oxybis[N-(2-hydroxy-5-bromobenzilidine)aniline] and 4,4′-oxybis[N-(2-hydroxynaphthalidine) aniline] were synthesized by the condensation of 4,4′-oxydianiline with three aromatic aldehydes. The structures of the monomers and polymers were confirmed by Fourier Transform infrared spectroscopy, UV–visible, ¹H-NMR and ¹³C-NMR spectroscopic techniques. Morphology of the synthesized polymers was characterized using scanning electron microscope. The thermal stability of the polymers is evidenced by high carbines residue obtained in TGA. Fluorescence spectra showed that the emission maxima centred in the region 420–460 nm for all the compounds with large stokes shift values (?λ_ST). Electrical conductivity of iodine-doped polymers was measured by four-point probe technique. The synthesized polymers have shown good electrical conductivity on iodine doping, and it increases with the increase in iodine vapour contact time. The self-extinguishing property of the synthesized polymers was studied by the calculation of the limiting oxygen index values with van Krevelen’s equation.     

Synthesis, Characterization and Optimum Reaction Conditions of Oligo-N, N′-bis (2-hydroxy-1-naphthalidene) Thiosemicarbazone

The oxidative polycondenzation reaction conditions of N, N-bis (2-hydroxy-1-naphthalidene) thiosemicarbazone (HNTSC) using air oxygen, H₂O₂ and NaOCl were studied in an aqueous alkaline medium between 50–90°C. Oligo-N, N-bis (2-hydroxy-1-naphthalidene) thiosemicarbazone was characterized by ¹H-NMR, FT-IR, UV-Vis, size exclusion chromatography (SEC) and elemental analysis techniques. Solubility testing of oligomer was investigated using organic solvents such as DMF, THF, DMSO, methanol, ethanol, CHCl₃, CCl₄, toluene acetonitrile, ethyl acetate, concentrated H₂SO₄ and an aqueous alkaline solution. Using NaOCl, H₂O₂ and air O₂ oxidants, conversion to oligo-N, N-bis (2-hydroxy-1-naphthalidene) thiosemicarbazone (OHNTSC) of N, N-bis (2-hydroxy-1-naphthalidene) thiosemicarbazone was found to be 85, 80 and 76%, respectively, in an aqueous alkaline medium. According to the SEC analyses, the number-average molecular weight, weight-average molecular weight and polydispersity index values of OHNTSC synthesized were found to be 1050 gmol^–1 1715 gmol^–1 and 1.63, using NaOCl, and 2137, 2957 gmol^–1 and 1.38, using air O₂ and 2155 gmol^–1 4164 gmol^–1 and 1.93, using air H₂O₂, respectively. Also, TG analysis was shown to be unstable of oligo-N, N-bis (2-hydroxy-1-naphthalidene) thiosemicarbazone against thermo-oxidative decomposition. The weight loss of OHNTSC was found to be 97.29% at 900°C.     

Tricarbonyl rhenium complex of 2,6-bis(8′-quinolinyl)pyridine: Synthesis,spectroscopic characterization,X-ray structure and DFT calculations

2,6-Bis(8′-quinolinyl)pyridine (bqp) reacts with pentacarbonyl rhenium chloride in toluene to give fac,fac-[Re(bqp-κ³N)(CO)₃](Cl). X-ray crystallographic data on fac,fac-[Re(bqp-κ³N)(CO)₃](Cl) show that the bqp ligand and carbonyl ligands achieve a mutually facial arrangement. A mix of MLCT and π–π* ligand centered transitions is observed for the low energy UV–vis absorption bands. The complex is emissive in solution and appears to be dominated by a MLCT-based process. Electronic and structural characteristics are supported by DFT calculations.     

Synthesis and properties of aromatic polyesters and brominated polyesters derived from α,α′-bis(4-hydroxyphenyl)-1,4(or 1,3)-diisopropylbenzene

The interfacial polycondensation technique was used for the preparation of polyarylates and brominated polyarylates. Polyarylates and brominated polyarylates were prepared by mixing a solution of diacid chloride such as terephthaloyl chloride, isophthaloyl chloride, or their mixture in dichloromethane with an aqueous alkaline solution of ,-bis(4-hydroxyphenyl)-1,4(or 1,3)-diisopropylbenzene or ,-bis(4-hydroxy-3,5-dibromophenyl)-1,4(or 1,3)-diisopropylbenzene using triethylbenzylammonium chloride as the phase transfer agent. Moderate to high molecular weight polyarylates with _inh up to 1.27 dL/g were obtained, and most of them could be cast into tough and flexible films depending on the polymer composition. In general, polymers containing more 1,3-isomer or isophthaloyl chloride moieties gave transparent and flexible films and had lower glass transition temperatures and higher solubility. Although these polymers have two isopropylidene linkages in their repeating units, they still exhibit moderately high thermal stability and show no obvious weight loss before 400 °C. The introduction of bromine on the polymer backbone caused a decrease of inherent viscosity, crystallinity, and thermal stability of the polyarylates, while causing an increase in glass transition temperature and a great enhancement of fire retardancy.     

Synthesis of soluble polyarylenes containing alternating 4,4′-(1,1′-binaphthyl) and 4,4′-(3,3′-diphenyl)biphenyl structural units

Summary The synthesis and Ni(0) catalyzed homocoupling polymerization of 4,4-bis[5-(trifluoromethanesulfonyloxy)-2-biphenylyl]-1, 1-binaphthyl (9) are described. This polymerization reaction produces a soluble polyarylene containing alternating 4,4-(1,1-binaphthyl) and 4,4-(3,3-diphenyl)biphenyl structural units.     

Synthesis,structure and characterization of neat Zn2(OH)2 diamond-core chains linked through 2,2′,4,4′-biphenyl-tetracarboxylate

Reaction of 2,2′,4,4′-biphenyltetracarboxylic acid (2,4-H₄bptc), Zn(NO₃)₂ · 6H₂O in the presence of NaOH hydrothermally at 180 °C affords the first 2,4-H₄bptc complex [Zn₃(μ₃-OH)₂(2,4-bptc)]_n · 2nH₂O (1). Crystal structure indicates that 1 is Zn₂(OH)₂ diamond-core chains linked through 2,2′,4,4′-biphenyltetracarboxylate. 1 was characterized by TG, IR and fluorescence spectra. 1 is the first example of 2,4-H₄bptc complex and also first neat Zn₂(OH)₂ diamond-core chains.     

Synthesis and spectroscopic and electrochemical properties of new ligand 1,3-bis(4′-methyl-2,2′-bipyridin-4-yl)propan-2-one and its ruthenium(II) complexes

A new bridging ligand, 1,3-bis(4′-methyl-2,2′-bipyridin-4-yl)propan-2-one (L) and its mono- and dinuclear Ru(II) complexes have been synthesized and characterized. The carbonyl group in L keeps its character and does not affect the Ru(II) moieties. In addition, the two Ru(II) terminuses of the dinuclear complex have no interaction through the bridging linkage.     

Synthesis, characterization, and sorption properties of water-insoluble poly(2-acrylamido-2-methyl-1-propane sulfonic acid)–montmorillonite composite

The sorption properties of composites based on 2-acrylamido-2-methyl-1-propane sulfonic acid and montmorillonite are presented. Gel-type composites were obtained via in situ polymerization. Resin particles presented exfoliated morphologies, as suggested by X-ray diffraction. The addition of montmorillonite resulted in enhanced mechanical properties, as evaluated by Vickers microhardness tests. The swelling performances of the resins exhibited a fast initial water uptake, reaching the maximum absorption capacity after less of 1 h of contact. A batch procedure was used to evaluate the sorption characteristics of the composites, and the effects of pH, montmorillonite content, and time were studied. The composites showed high adsorption capacities at pH values of 3.0 and 5.0, and the addition of montmorillonite did not result in a significant enhancement of their adsorption capacity. The equilibrium adsorption performance can be described by the Langmuir isotherm, while kinetic experiments revealed an excellent agreement with the pseudo-second-order model.     

Synthesis and characterization of iron(II) and iron(III) complexes with a tridentate O,N,O′-ligand

The coordination chemistry of the ligand precursor 1-benzoyl-4,5-dihydro-3,5-bis(trifluoromethyl)-1H-pyrazol-5-ol (1a) to iron(II) acetate was studied. In dependence of the added co-ligand different complex geometries were observed. In case of 4-dimethylaminopyridine (DMAP) as co-ligand an octahedral iron(II) complex was found with an O,N,O′-coordination of the tridentate ligand (1a-2H), in which the ligand is planar, the oxygen donors are trans to each other, and the nitrogen donor is in a cis position. The other coordination sites on the iron center are occupied by DMAP ligands. In contrast to that, with triphenylphosphane as the co-ligand an oxidation process took place, which revealed an octahedral iron(III) complex with a comparable geometry for the tridentate ligand (O,N,O′-coordination, 1a-2H) demonstrating the usefulness of 1a-2H to stabilize different oxidation states. The additional coordination sites are occupied by one triphenylphosphane oxide and ethoxide ligands. Interestingly, the ethoxide ligands act as bridging ligands to form a bimetallic complex.