N-H?S hydrogen bonding in 2-mercapto-5-methyl-1,3,4-thiadiazole. Synthesis and crystal structures of mercapto functionalised 1,3,4-thiadiazoles

The synthesis and crystal structures of three mercapto functionalised 1,3,4-thiadiazoles and the crystal structure of 2-mercapto-5-methyl-1,3,4-thiadiazole are described. In the solid state, 2-mercapto-5-methyl-1,3,4-thiadiazole 1 forms a thioamide tautomer as shown by FTIR and Raman spectroscopy as well as X-ray crystallography and as theoretically predicted. The molecules are connected to form chains via N-H?S hydrogen bonds with N?S=328.3 pm. Bis(2-methyl-1,3,4-thiadiazolyl)-5,5′-disulfide 2, the disulfide of 1, as well as 2-(tert-butyldithio)-5-methyl-1,3,4-thiadiazole 3 and 2,5-bis(tert-butyldithio)-1,3,4-thiadiazole 4 have been synthesised and characterised by vibrational spectroscopy and X-ray diffraction.     

FT-Raman spectroscopy of the reaction of polybutadiene with mercapto-thiadiazoles

Mercapto-thiadiazoles having potential anti-wear behaviour are reacted with polymers with existing viscosity index-improving properties in order to produce materials which may find a use as multifunctional lubricant additives. 2,5-Dimercapto-1,3,4-thiadiazole, 2-amino-5-mercapto-1,3,4-thiadiazole and 2-methyl-5-mercapto-1,3,4-thiadiadiazole were reacted with low MW polybutadiene containing vinyl-1,2, cis-1,4 and trans-1,4 (C=C) groups. The reactions were monitored using FT-Raman spectroscopy in order to determine quantitatively the consumption of the individual structural units when reacted with thiadiazoles. 2,5-Dimercapto-1,3,4-thiadiazole reacted readily with the polybutadiene, achieving 80% reaction within a few hours. The thiadiazole reacted selectively with the order of addition being cis>vinyl>trans. 2-Amino-5-mercapto-1,3,4-thiadiazole and 2-methyl-5-mercapto-1,3,4-thiadiazole were found to react more slowly and hence to a lesser extent (40 and 25%, respectively) over a similar time scale.     

Synthesis and reactivity of acyclic and macrocyclic uracils bridged with five-membered heterocycles

Replacement of terminal atoms of Br in 1,3-bis(bromopentyl)-5(6)-substituted uracils with 2-mercapto-5-methyl-1,3,4-thiadiazole, 2,5-dimercapto-1,3,4-thiadiazole, 2-mercaptoimidazole, and 2-mercaptobenzimidazoles resulted in a series of acyclic compounds and isomeric heterocyclophanes. Structures of macrocyclic regioisomers were unambiguously determined by NMR data. One of the regioisomers exhibits a hypochromic effect with respect to model compounds. The acyclic uracils obtained bridged with five-membered heterocycles are alkylated with methyliodide and methyl tosylate, and oxidated with m-CPBA, H₂O₂, and I₂.     

Polymorphism of KNaNbOF5 crystals

X-ray crystallography is used to analyze the concomitant polymorphism of KNaNbOF₅ crystals. The second ??-modification of the compound, crystallizing in the tetragonal crystal system is found for the first time: space group P4/nmm, a = 5.9352(2) ?, c =8.5487(5) ?, V = 301.14(2) ?³, Z = 2, R1 = 0.0095. Parameters of the orthorhombic noncentrosymmetric structure of the ??-phase, previously described by Poeppelmeier et al. (J. Am. Chem. Soc., 129, 13963?C13969 (2007)), are refined and a comparative analysis of both structures is performed. The structures are characterized by the complete ordering of oxygen and fluorine atoms, the Nb-O distance in the ??-phase (1.738(1) ?) being noticeably longer than that in the ??-phase (1.709(2) ?). In ??-KNaNbOF₅, alternating NbOF₅ and NaOF₅ octahedra share vertices, while in ??-KNaNbOF₅, they share both vertices and edges. The existence of the non-polar centrosymmetric ??-modification of KNaNbOF₅ cancels the assumption of the substantial contribution of potassium cations to the polar structure of ??-KNaNbOF₅.     

Hydrothermal Synthesis,Conversion Reaction,and Crystal Structure of 2-D 2-bromo-1,4-benzenedicarboxylate Copper(II) Complex with 2,2′-bipyridine

A fully deprotonated 2-bromo-1,4-benzenedicarboxylate copper(II) complex, [Cu(bbdc)(2,2′-bipy)](H₂O) (bbdc= 2-bromo-1,4-benzenedicarboxylate dianion, 2,2′-bipy=2,2′-bipyridine), was synthesized under hydrothermal conditions. This compound also can be prepared from the partly deprotonated [Cu(Hbbdc)₂(2,2′-bipy)] under basic and hydrothermal conditions. The crystal structure consists of infinite chains of [Cu₂(μ₄-bbdc)]²⁺ building blocks connected by bis-monodentate bbdc ligands and exhibits an extended 2-D architecture. Electronic supplementary material Electronic supplementary material is available for this article at and accessible for authorised users.     

Hydrothermal synthesis, characterization and fluorescence property of a novel layered fluorinated gallium phosphite with heptameric building unit

A new fluorinated gallium phosphite, Ga₃F₂(2,2′-bipy)₂(HPO₃)₂(H_1.5PO₃)₂1, which is the first layered gallium phosphite with neutral framework, has been hydrothermally synthesized in the presence of 2,2′-bipyridine (2,2′-bipy) acting as a ligand. The as-synthesized product was characterized by single-crystal X-ray diffraction, powder X-ray diffraction, IR spectroscopy, thermogravimetric analysis (TGA), ICP-AES and elemental analyses and fluorescent spectrum. Single-crystal X-ray diffraction analysis reveals that compound 1 crystallizes in the monoclinic space group C2/c (No. 15) with cell parameters a=17.633(3) Å, b=9.883(2) Å, c=16.793(3) Å, β=109.88(3)°, V=2752.1(9) Å³ and Z=4. The construction of two-dimensional (2D)-layered structure in compound 1 may be viewed as the assembly of heptameric building unit, which is the first to be found in gallium phosphate/phosphite. The heptameric building unit exists in two types of configuration, which alternately connect through oxygen atoms from HPO₃ pseudo-pyramids to form a layer with 10-membered ring windows viewed along the a-axis. The adjacent layers are stably packed together and exhibit interesting three-dimensional (3D) supramolecular array via π-π interactions of the 2,2′-bipy groups. Additionally, compound 1 shows strong fluorescent property in solid state at room temperature.     

一维配位聚合物2-巯基-5-甲基-1,3,4-噻重氮锌钴的合成、结构与性能

于中温混合溶剂热体系中合成出2种同构的一维配位聚合物[Zn(MMTT)2]n和[Co(MMTT)2]n(MMTT=2-巯基-5-甲基-1,3,4-噻重氮), 并进行了单晶结构解析、红外、热重、荧光及磁性等表征. 晶体同属单斜晶系, C2/c空间群. [Zn(MMTT)2]n的晶胞参数: a=1.40432(8) nm, b=1.13824(5) nm, c=0.72378(4) nm, β=101.425(3)°, V=1.13400(10) nm3; [Co(MMTT)2]n的晶胞参数: a=1.4001(9) nm, b=1.1142(9) nm, c=0.7403(3) nm, β=107.84(6)°, V=1.0994(12) nm3. 化合物中金属原子采取四面体构型, 与MMTT配体分子相互连接形成无限一维链; 链与链之间通过配体间弱的C-H···S 氢键连接而形成三维超分子网络结构.     

Design,synthesis and magnetic properties of a ladderlike complex constructed by secondary building units

A secondary building unit (SBU), [Ni(2,2′-bipy)(5-npa)(H₂O)] _n [where 2,2′-bipy = 2,2′-bipyridine, 5-npa = 5-nitroisophthalic dianion], was synthesized as starting material of a polystep reaction. A ladderlike complex (LLC) Ni(II) coordination polymer, {[Ni(2,2′-bipy)(5-npa)(4,4′bipy)_0.5]·(H₂O)} _n , was constructed by polystep reaction using this SBU. In LLC, two SBUs were cross-linked by 4,4′-bipy [where 4,4′-bipy = 4,4′-bipyridine] forming a 1-D ladderlike structure. The magnetic properties of the LLC and SBU are discussed.     

Spectroscopic characterization and crystal structure of cis-Bis(N-(2-benzoyl)-N′,N′-diphenylthioureato-k 2O,S)nickel(II)

The title compound [Ni(C₂₀H₁₅N₂OS)₂] is prepared by the reaction of metal acetate with the corresponding acylthiourea derivative. The complex is characterized by elemental analysis, IR, ¹H and ¹³C NMR, and its structure is determined by single crystal X-ray diffraction. The Ni(II) ion is coordinated by the S and O atoms of two N-benzoyl-N??,N??-diphenylthiourea ligands in a slightly distorted square-planar coordination geometry. The two O and two S atoms are mutually cis to each other. The substance crystallizes triclinic (P-1 space group) with cell dimensions a = 10.7262(9) ?, b = 12.938(3) ?, c = 14.2085(12) ?, ?? = 74.650(4)°, ?? = 78.398(4)°, ?? = 68.200(5)°, and two formula units in the unit cell. The structure is very close to the related N-(2-furoyl) Ni complex reported previously.     

Synthesis and characterization of a Cu(II) complex of 2-benzylmercapto-5-methyl-1,3,4-thiadiazole (C10H10N2S2)

A Cu(II) complex of 2-benzylmercapto-5-methyl-1,3,4-thiadiazole was synthesized and characterized. The crystal structure of the copper complex and the free ligand were determined by single-crystal X-ray diffraction at room temperature: {[Cu(C₁₀H₁₀N₂S₂)₂(Cl)₂], P 1 triclinic, a = 8.1450(2) Å, b = 8.1690(2) Å, c = 10.8180(3) Å, α = 97.4040(12)°, β = 101.6270(11)°, γ = 116.1431(14)°; C₁₀H₁₀N₂S₂ ligand, Pbca orthorhombic, a = 8.7938(7) Å, b = 9.6491(7) Å, c = 25.3552(18) Å}. The metal complex framework consists of discrete units that provide crystalline stability through a network of van der Waals contacts. The Cu(II) is coordinated by two chloride ions and two 2-benzylmercapto-5-methyl-1,3,4-thiadiazole monodentate ligands showing a distorted square planar configuration. Both thiadiazole ligands coordinate through the N atom bonded to the benzylthio substituted C atom.

The FTIR spectroscopic data are consistent with this structural model. Analysis of the magnetic susceptibility from 5 K to room temperature indicates the presence of paramagnetic Cu(II), confirmed by the EPR spectrum.     

SYNTHESIS,CHARACTERIZATION AND CRYSTAL STRUCTURE OF DIAQUADI(2,2′'-BIPYRIDINE)DI(DICHLOROACETATO)LANTHANIDE(III) MONODICHLOROACETATO

Abstract

The title complexes, diaquadi(2,2″-bipyridine)di(dichloroacetato)lanthanide(III) monodichloroacetato [Ln(CHCl₂COO)₂(2,2′-bipy)₂(H₂O)₂]⁺(CHCl₂COO)^?(Ln = Dy, Ho, Tm, Er, Yb], were obtained and characterized. [Er(CHCl₂COO)₂(2,2′-bipy)₂(H₂O)₂]⁺(CHCl₂COO)^? crystallizes in the mooclinic space group P2₁/n with Z = 4. Cell dimensions are a = 15.886(9), b = 13.758(2), c = 16.343(4)Å, β = 113.31(3)°, and the structure was refined to an R of 0.049 for 3415 observed reflections. The Er(III) ion exhibits a distorted, square antiprismatic configuration. Four N atoms of 2,2′-bipy and four O atoms from two dichloroacetato and two water ligands are coordinated. One dichloroacetato group lies outside the polyhedron and is connected with water ligands by hydrogen bonds.     

Hydrothermal synthesis,crystal structure and fluorescence of a cyclic dimer copper compound constructed by 2-nitrobenzenedicarboxylate

The reaction of 2-nitro-1,4-benzenedicarboxylic acid (H₂nbdc) and 2,2′-bipyridine (2,2′-bipy) with CuCl₂ under hydrothermal conditions gives rise to a cyclic dimer [Cu(nbdc)(2,2′-bipy)(H₂O)]₂ · 2H₂O (1). X-ray structural analysis revealed that 1 crystallizes in a monoclinic space group P2₁/c with a = 7.3801(13) Å, b = 15.305(3) Å, c = 16.333(3) Å, β = 92.951(4)°, V = 1842.5(6) ų, and Z = 2. Compound 1 represents the first cyclic dimeric example with 1,4-benzenedicarboxylate or its derivatives, in which two carboxylates of the nbdc are nearly perpendicular due to the steric effect by the nitro group. Compound 1 also displays strong fluorescent emission in the solid state.     

Synthesis and crystal structure of the complex N,N-dimethylanilinium dicitratoborate monohydrate

N,N-Dimethylanilinium dicitratoborate monohydrate [C₆H₅NH(CH₃)₂][(C₆H₆O₇)₂B]·H₂O (I) was synthesized for the first time. Single crystals were obtained in an aqueous solution; the crystal structure was studied by X-ray crystallography. Crystals of I are triclinic, space group $P\bar 1$ , a = 9.7017(2) ?, b = 11.0475(2) ?, c = 12.6282(2) ?, ?? = 106.595(2)°, ?? = 106.931(1)°, ?? = 103.568(1)°, V = 1163.97(4) ?³, Z = 2, ??_calc = 1.516 g/cm³. The structural units of compound 1 are large complex dicitratoborate anions with a spiran structure, N,N-dimethylanilinium cations, and crystal water molecules. The crystal packing is a three-dimensional framework. A hydrogen-bond system is formed by seven independent contacts O(N)-H??O.     

X-ray crystallographic study of crystalline products of interaction of lanthanum(III) nitrate, ammonium tetra(isothiocyanato)diamminechromate(III) and dimethyl sulfoxide in an aqueous solution

A new complex [La(Dmso)₉][Cr(NH₃)₂(NCS)₄]₃ · 4DMSO (I) was synthesized by the reaction of lanthanum(III) nitrate, ammonium tetra(isothiocyanato)diamminechromate(III), and dimethyl sulfoxide and structurally characterized. The crystals are monoclinic, space group C2/c, a = 14.5550(4) ?, b = 25.8826(7) ?, c = 25.5262(6) ?, ?? = 96.5180(10)°, V = 9554.1(4) ?³, Z = 4, ??_calc = 1.467 g/cm³. A freshly precipitated fine crystalline powder corresponds to compound I according to X-ray powder diffraction. However, long-term crystallization leads to formation of at least another four crystalline products: two of them were not characterized because of the poor quality of crystals, the third product was identified as the known complex La(NO₃)₃(Dmso)₄, and the fourth product was identified by X-ray crystallography as the mixed-ligand complex [La(Dmso)₆(NO₃)(NCS)][Cr(NH₃)₂(NCS)₄] · 3Dmso (II) with an island structures. The crystals are monoclinic, space group P2₁/n, a = 18.8026(8) ?, b = 14.9453(5) ?, c = 20.4411(9) ?, ?? = 99.2720(10)°, V = 5669.1(4) ?³, Z = 4, ??_calc = 1.500 g/cm³.     

铜三氟柳配合物的合成,结构和仿生催化溴化

合成了一系列2-羟基-4-三氟甲基苯甲酸（h₂tba）-铜配合物：[Cu（htba）₂（pz）₂]（1）,[Cu（htba）（2,2''-bipy）]（htba）（2）和[Cu（htba）₂（4,4''-bipy）]（3）（h₂tba=2-羟基-4-三氟甲基苯甲酸,pz=吡唑,2,2''-bipy=2,2''-联吡啶,4,4''-bipy=4,4''-联吡啶）,并且通过元素分析、红外光谱、紫外光谱、粉末X射线衍射、单晶X射线衍射和热重分析方法对配合物结构进行了表征。这些配合物能够在过氧化氢和溴化物存在的条件下催化苯酚红溴化,并且展示出了较高的催化溴化活性。     

Two new supramolecular assemblies based on Keggin-type polyoxometalates through AgO and ππ stacking interactions

Two new supramolecular assemblies based on Keggin-type polyoxometalates, [Ag₃(4,4′-bipy)₂(2,2′-bipy)₂][Ag(2,2′-bipy)₂][{Ag(2,2′-bipy)}HSiW₁₁VO₄₀] (1) and [Ag₃(4,4′-bipy)₂(2,2′-bipy)₂][Ag(2,2′-bipy)₂][{Ag(2,2′-bipy)}PW₁₁VO₄₀] (2) (4,4′-bipy = 4,4′-bipyridine, 2,2′-bipy = 2,2′-bipyridine), have been synthesized under the hydrothermal conditions and structurally characterized by IR, XPS, TG and single-crystal X-ray diffraction. Compound 1 has a 2D layer network structure via weak Ag^...O interactions. Compound 2 is isostructural with compound 1. In addition, the fluorescence of compound 1 is reported.     

Preparation, photophysical, and electrochemical properties of two polynuclear Ru(II) polypyridyl complexes containing imidazole-based ligands

A tripodal ligand L¹ and dipodal ligand L² containing imidazole rings have been synthesized by the reaction of 1,10-phenanthroline-5,6-dione with 2,2??-bipyridine-4,4??-dicarbaldehyde and 4-methyl-2,2??-bipyridine-4??-carbaldehyde, respectively, in the presence of ammonium acetate. Both ligands have two kinds of nonequivalent coordinating sites: one involving the phenanthroline moiety and the other involving the 2,2??-bipyridine moiety. The Ru(II) complexes, [(bpy)₆Ru₃(L¹)](PF₆)₆ and [(bpy)₄Ru₂(L²)](PF₆)₄ (bpy?=?2,2??-bipyridine), have been obtained by refluxing Ru(bpy)₂Cl₂·2H₂O with each ligand in solution. The two complexes display MLCT absorptions at 465 and 480?nm, respectively, and emission at 665 and 675?nm, respectively, in CH₃CN solution. Electrochemical studies of both complexes show one Ru(II)-centered oxidation at around 1.29?V and three ligand-centered reductions.     

Synthesis, crystal structure, and luminescence properties of the tetranuclear complex of cadmium(II) acetate with 4,4′-(1,4-phenylenediisopropylidene)bis-aniline

The complex compound [CdL_1.25(CH₃CO₂)₂(H₂O)], where L = NH₂-C₆H₄-C(CH₃)₂-C₆H₄-C(CH₃)₂-C₆H₄-NH₂ was synthesized and its crystal structure was determined. The crystals are triclinic, space group P $ \bar 1 $ , a = 10.160(1) ?,b = 17.442(1) ?, c = 20.232(1) ?, ?? = 67.93(1)°, ?? = 87.22(1)°, ?? = 77.65(1)°, V = 3340.2(4) ?³, ??_calc = 1.392 g/cm³, Z = 4. The structure contains two crystallographically non-equivalent Cd²⁺ ions, each coordinating two nitrogen atoms of two ligands L, four oxygen atoms of two bidentate acetate groups, and one water molecule. The coordination polyhedron of Cd²⁺ ions is anirregular sevenvertex polyhedron. The interaction of cadmium with ligands L gives rise to centrosymmetric tetranuclear complexes [Cd₄L₅].     

铜三氟柳配合物的合成,结构和仿生催化溴化

合成了一系列2-羟基-4-三氟甲基苯甲酸（h₂tba）-铜配合物：[Cu（htba）₂（pz）₂] （1）,[Cu（htba）（2,2''-bipy）]（htba） （2）和[Cu（htba）₂（4,4''-bipy）] （3）（h₂tba=2-羟基-4-三氟甲基苯甲酸,pz=吡唑,2,2''-bipy=2,2''-联吡啶,4,4''-bipy=4,4''-联吡啶）,并且通过元素分析、红外光谱、紫外光谱、粉末X射线衍射、单晶X射线衍射和热重分析方法对配合物结构进行了表征。这些配合物能够在过氧化氢和溴化物存在的条件下催化苯酚红溴化,并且展示出了较高的催化溴化活性。     

The reaction of ammonium tetra(isothiocyanato)diamminechromate(III) with ?-caprolactam in aqueous solution. Revised refinement of the structure of (HCpl2)3[Cr(NCS)6]

A reaction of ammonium tetra(isothiocyanato)diamminechromate(III) (ammonium reineckate) with ?-caprolactam in aqueous solution at different pH values gave the novel complexes (NH₄)[Cr(NH₃)₂(NCS)₄] · 7Cpl (I), (NH₄)[Cr(NH₃)₂(NCS)₄] · 2.5Cpl · 0.5(H₂O) (II), and (HCpl₂)[Cr(NH₃)₂(NCS)₄] (III), where Cpl is ?-caprolactam (?-C₆H₁₁NO). The crystals of complexes I?CIII are triclinic, space group $P\bar 1$ ; I: a = 12.7058(4) ?, b = 13.2544(4) ?, c = 19.4487(7) ?, ?? = 105.2360(10)°, ?? = 106.6410(10)°, ?? = 91.5290(10)°, V = 3009.37(17) ?³, ??_calc = 1.245 g/cm³, Z = 2; II: a = 12.3144(5) ?, b = 12.6518(5) ?, c = 23.3300(8) ?, ?? = 75.4580(10)°, ?? = 80.0760(10)°, ?? = 61.0830(10)°, V = 3074.1(2) ?³, ??_calc = 1.358 g/cm³, Z = 4; III: a = 6.4701(4) ?, b = 12.5973(9) ?, c = 16.5556(12) ?, ?? = 108.769(2)°, ?? = 98.543(2)°, ?? = 90.345(2)°, V = 1261.36(15) ?³, ??_calc = 1.437 g/cm³, Z = 2. The structure refinement for (HCpl₂)₃[Cr(NCS)₆] (IV) was revised. Like complex III, complex IV contains the cation (HCpl₂)⁺ stabilized by a strong hydrogen bond between the O atoms of the ?-caprolactam molecules; the cation was structurally characterized for the first time.