One Dimensional Hydrogen Bonded Arrangement in New Schiff-Base Compound (<Emphasis Type="Italic">E</Emphasis>)-2-(2,5-dimethoxybenzylideneamino)phenol (1): Synthesis,Characterization, Crystal Structure and Conformational Studies

Abstract  

New Schiff-base compound (E)-2-(2,5-dimethoxybenzylideneamino)phenol (1) was synthesized and characterized by elemental analyses, FT-IR and ¹H-NMR spectroscopy and single crystal X-ray diffraction. Molecular orbital calculation has been carried out for 1 by using HF method at 6-31G basis set. The title compound 1 crystallizes in monoclinic system, space group C2/c, with a = 19.4581(13) ?, b = 9.5805(5) Ǻ, c = 13.8431(7) Ǻ, β = 93.471(2)°, V = 2575.9(3) Ǻ³ and Z = 8. In the crystal structure two molecules are stabilized by a pair of intermolecular O1–H1···N1ⁱ hydrogen bonds. The dimeric units are further linked via C6–H6···O3ⁱⁱ hydrogen bond.     

Experimental and Semi-Empirical and DFT Calculational Studies on (<Emphasis Type="Italic">E</Emphasis>)-2-[(2,4-Dichlorophenylimino) methyl]-<Emphasis Type="Italic">p</Emphasis>-cresol

Abstract  

The molecular and crystal structure of the title compound, C₁₄H₁₁Cl₂NO, has been determined by X-ray single crystal diffraction technique. The compound crystallizes in the orthorhombic, space group Pbca with unit cell dimensions a = 7.5537(10) ?, b = 11.5518(13) ?, c = 29.760(4) ?, M _r  = 280.14, V = 2596.8(6) ?³, Z = 8, R ₁ = 0.065 and wR ₂ = 0.191. The title compound exists in the enol–imine tautomeric form with a strong intramolecular O–H···N hydrogen bond. The dihedral angle between the two benzene rings is 37.66(15)°. The asymmetric unit in the crystal structure contains only one neutral molecule. Calculational studies were performed by using AM1, PM3, PM6 semi-empirical and DFT methods. Geometry optimizations of compound have been carried out by using three semi-empirical methods and DFT method and bond lengths, bond and torsion angles of title compound have been determined. Dipole moments (Debye) and the energy parameters of compound (kcal/mol) were calculated by using above mentioned calculation methods. Atomic charge distribution has been obtained from AM1, PM3, PM6 and DFT. In order to determine conformational flexibility on the molecule, molecular energy profile of the title compound was obtained with respect to the selected torsion angle T(N1–C7–C1–C2), which is varied from −180° to +180° in every 10 via PM3 semi-empirical method.     

Structure of a New Bioactive Agent Containing Combined Antibacterial and Antifungal Pharmacophore Sites: 4-{[(<Emphasis Type="Italic">E</Emphasis>)-(5-Bromo-2-hydroxyphenyl)methylidene]amino}-<Emphasis Type="Italic">N</Emphasis>-(5-methyl-1,2-oxazol-3-yl)benzenesulfonamide

Abstract  

The title compound (3), C₁₇H₁₄BrN₃O₄S, is a Schiff base compound of 5-bromosalicylaldehyde (1) and sulfamethoxazole (2). The structure of (3) was determined by spectral (IR, ¹H and ¹³C NMR), elemental analyses and X-ray diffraction data. Compound (3) crystallizes in the monoclinic space group C2/c, with a = 31.936(3), b = 6.2571(5), c = 16.903(1) ?, β = 94.867(8), V = 3365.5(5) ?³, Z = 8. In the molecule of compound (3), the molecule is bent at the S atom with a C–SO₂–NH–C torsion angle of −86.3(3)°. Pairs of molecules, related by inversion centres, form intermolecular N–H···N hydrogen bonds to produce a dimer. An intramolecular phenolic O–H···N hydrogen bond is also formed. Intermolecular hydrogen bonding and π–π stacking hold the molecules together. The average distance between stacked benzene ring planes is 3.625(2) ?.     

Convenient Route to Alkylene Dithiophosphato Ligands: Synthesis and Crystallographic Analysis of [OCH<Subscript>2</Subscript>CMe<Subscript>2</Subscript>CH<Subscript>2</Subscript>OPS<Subscript>2</Subscript>HNEt<Subscript>3</Subscript>]

Abstract  

Triethylammonium salts of O,O′-alkylene dithiophosphato like OGOPS₂HNEt₃, [where, G = –CH₂CMe₂CH₂–(1), –CH₂CEt₂CH₂–(2), –CMe₂CH₂CHMe–(3) and –CMe₂CMe₂–(4)] have been synthesized in quantitative yield by the direct reaction of P₂S₅ with 1,2- and 1,3-substituted glycols in presence of triethylamine, Et₃N, in 1:2:2 molar stoichiometry in toluene. These have been mainly characterized by molecular weight, IR and NMR (¹H, ¹³C and ³¹P) spectroscopic studies. Single crystal X-ray structure analysis of [OCH₂CMe₂CH₂OPS₂HNEt₃] reveals that phosphorus atom is tetrahedrally bonded to two sulfur atoms and two oxygen atoms in the ring and the molecule exists as discrete cation and anion. The structure is stabilized by cation–anion N–H···S hydrogen bonded interactions. Antiparallel pattern of triethylammonium ion is sandwiched within the two-dimensional layers of the ring system.     

Two New 2-Benzoylbenzoate Metal Complexes with Bapen: Synthesis,Spectroscopic and Crystal Structures

Abstract  

Coordination compounds of compositions [Ni(bba)₂(bapen)] (1) and [Cu(bba)₂(bapen)]0.5H₂O (2), where bba = 2-benzoylbenzoate, bapen = N,N′-bis(3-aminopropyl)ethylenediamine, have been prepared. The crystal and molecular structure of (1) and (2) were determined by X-ray analysis. Nickel and copper atoms are six-coordinated by four N atoms of amine and O donor atoms of 2-benzoylbenzoate anions, whereas 0.5 water molecule is situated outside the coordination sphere in (2). The calculated ∆(OCO) values are consistent with presence of monodentate carboxylate. Thermal analysis show that the mass losses of 1 in the temperature ranges 240–343 °C correspond to the decomposition of bba ligands, while the mass losses of 2 in the temperature ranges 105–125 °C correspond to the decomposition of crystal lattice water molecule.     

Structural and Spectroscopic Study of Cu(II) Pyridine-2,6-dicarboxylate Complex with 2-Ethylimidazole

Abstract  

A mononuclear copper(II) complex, [Cu(pydca)(2-Etlm)(H₂O)] (1) (H₂pydca = pyridine-2,6-dicarboxylic acid, 2-Etlm = 2-ethylimidazole), has been synthesized and characterized by elemental analyses, IR, UV–Vis, TG-DTA and single crystal X-ray diffraction. The complex 1 is in the orthorhombic crystal system, space group Pbca and Z = 8. The structural analysis indicated that Cu(II) center is five coordinated in a slightly distorted square pyramidal geometry by one N and two O atoms from a 2,6-pyridine dicarboxylate dianion, one N atom from a 2-ethylimidazole ligand, and one O atom from a aqua molecule. This mononuclear motif of 1 is further assembled to 3D supramolecular framework through strong O–H···O and N–H···O hydrogen bonding interactions.     

Crystallographic and Conformational Analysis of [(<Emphasis Type="Italic">E</Emphasis>)-2-[(3-Chlorophenylimino)methy])-4-methoxyphenol]

Abstract  The crystal structure of C₁₄H₁₂ClNO₂ was determined by X-ray analysis. It crystallizes in the triclinic space group Pc with a = 12.5346(10) ?, b = 4.5101(3) ?, c = 12.0534(11) ?, α = 90.00o, β = 113.669(6)o, γ = 90.00o, Z = 2, Dx = 1.393 mg/m³, μ (MoK_α) = 0.298 mm⁻¹. The title compound is photochromic and molecule is non-planar. It adopts a phenol–imine tautomeric form with a strong intramolecular O–H···N hydrogen bond and a strong intermolecular C–H···O hydrogen bond. Minimum energy conformations AM1 were calculated as a function of the three torsion angles θ1(C10–C9–N1–C8), θ2(C9–N1–C8–C1) and θ3(N1–C8–C1–C6), varied every 10°. As in the X-ray experiment results, molecule has an angle that makes it non-planar between two aromatic rings in AM1 optimized geometry. Graphical Abstract  Molecular and crystal structure of [(E)-2-[(3-chlorophenylimino)methy])-4-methoxyphenol], C₁₄H₁₂ClNO₂, have been determined by single crystal X-ray diffraction study, and conformational analysis of the title molecule with respect to the selected torsion angle has been achieved by AM1 semi-empirical calculations.      

Structure of Triammonium <Emphasis Type="Italic">fac</Emphasis>-Trichloridotrioxidorhenate(VII) Chloride with <Emphasis Type="Italic">C</Emphasis><Subscript>3<Emphasis Type="Italic">v</Emphasis></Subscript> Crystallographic Symmetry of the Complex Anion

Abstract  

The unstable crystals of triammonium fac-trichloridotrioxidorhenate(VII) chloride have been obtained from ammonium rhenate(VII) solution in concentrated hydrochloric acid. The crystal structure consists of fac-trichloridotrioxidorhenate(VII) anions, chloride anions and ammonium cations. Each fac-trichloridotrioxidorhenate(VII) anion and each chloride anion lies in special position of 3m site symmetry (cell parameters: a = 9.026(3) Å; c = 7.690(4) Å; space group: P6₃ mc). The ammonium cation lies in special position of m site symmetry. The following anion geometrical parameters of the fac-trichloridotrioxidorhenate(VII) anion have been obtained: Re–O bond length of 1.720(2) Å, Re–Cl bond length of 2.5428(9) Å, the bond angles: O–Re–O of 103.5(1)° and Cl–Re–Cl of 79.8(1)°.     

Synthesis,Structural and Thermal Studies of a New Nickel Complex Containing 2-Aminopyrimidine and Thiocyanate Mixed Ligands with a Three-Dimensional Network Structure

Abstract  

A new nickel(II) complex formulated as, trans-[Ni(amp)₂(SCN)₂(H₂O)₂]·2H₂O (1), (amp = 2-aminopyrimidine) has been synthesized and characterized by elemental analysis, IR spectroscopy, its molecular and crystal structures were determined by X-ray crystal structure analysis and its thermal stability by TGA/DTA methods. 1 is a neutral complex and the central atom sits on an inversion center and is coordinated by two endocyclic nitrogen atoms of two 2-aminopyrimidine heterocycles, two oxygen atoms of two water molecules and two nitrogen atoms of SCN⁻ ions. 2-aminopyrimidine molecules, thiocyanate ions and water molecules are in trans position. Thermal methods confirm two co-crystallized water molecules in 1. π–π stacking interactions and extensive O–H···O, O–H···N, O–H···S and N–H···N hydrogen bonds contribute to the formation of a three-dimensional supramolecular structure. Crystal data for complex at 120 K: triclinic, space group P-1, a = 7.2026(14), b = 7.8332(15), c = 9.0270(17) ?, α = 67.694(3), β = 72.732(4), γ = 77.012(4), Z = 1, R ₁ = 0.0323.     

A Crystallographic Study of S-Methyl 2-(5-Chloro-2-Oxoindolin-3-ylidene)Hydrazinecarbodithioate

Abstract  

S-methyl 2-(5-chloro-2-oxoindolin-3-ylidene)hydrazinecarbodithioate (SM5ClISA) has been prepared from S-methyldithiocarbazate and 5-chloroisatin. The compound crystallized in monoclinic crystal system with space group P 2₁/n, Z = 4, V = 1201.85(7) ?³ and unit cell parameters a = 6.5466(2) ?, b = 7.5056(3) ?, c = 24.6509(8) ?, α = γ = 90° and β = 97.1434(18)°. The crystal structure reveals that the compound exists in the thione form with the chlorine occupies the fifth position in the isatin ring with the bond length of 1.739(2) ?. The 5-chloroisatin moiety is trans with respect to the C3–N2 and C3–S4 bonds whereas the methyl group of the dithiocarbazate moiety is cis with respect to the C3–N2 and C3–S5 bonds.     

Synthesis and Crystal Structure of 1,3-disubstituted-2-propyleno-1-one Containing Pyrazole Moiety

Abstract  

A series of novel 1,3-disubstituted-2-propyleno-1-one derivatives containing pyrazole ring were synthesized and characterized by IR, MS, H¹NMR and elemental analysis. The structure of C₂₅H₂₀N₂O₂ (3a) was determined by single crystal X-ray crystallography. C₂₅H₂₀N₂O₂ is monoclinic with space group P21/c and cell constans: a = 9.863(2)?, b = 20.054(4)?, c = 10.274(2)? V = 2028.0(7)?³ and Z = 4. In addition, the crystal structure was solved by direct methods and refined by full-matrix least-squares on F ² to final values of R1 = 0.0657 and wR2 = 0.1806, and it shows that the complex units are linked by non-classical hydrogen-bonding. The molecule adopts a trans configuration about the central C = C double bond. The crystal structure is stabilized by C–O···π intermolecular hydrogen bonds and π–π stacking interactions.     

The Tetrafluoroborate Salt of 4-Methoxybenzyl N-2-(dimethylamino)ethyl-N-nitrosocarbamate: Synthesis, Crystal Structure and DFT Calculations

Abstract  

The tetrafluoroborate salt of 4-methoxybenzyl N-2-(dimethylamino)ethyl-N-nitrosocarbamate was prepared in two steps, via the corresponding carbamate. Its crystal structure is monoclinic, space group P21/c. The unit cell dimensions are: a = 19.499(8) ?, b = 5.877(3) ?, c = 15.757(7) ?, α = 90°, β = 110.019(7)°, γ = 90°, V = 1696.5(12) ?³, Z = 4. The structure exhibits an unexpected, pseudo-gauche conformation with respect to the C2–C3 bond, due to a stabilizing hydrogen bond between the carbonyl oxygen (O1) and the hydrogen atom at the trialkylammonium center (H3n), with a distance between them of 2.37 ?. DFT calculations on the cation (B3LYP/6-31 + G(d)) confirm that the hydrogen bond stabilized gauche conformation is the global minimum structure.     

Synthesis,Structure and DNA-Binding Studies of Oxamido-Bridged Binuclear Copper(II) Complex: [Cu<Subscript>2</Subscript>(heap)](bipy)(ClO<Subscript>4</Subscript>)<Subscript>2</Subscript>

Abstract  

A new μ-oxamido-bridged copper(II)–copper(II) binuclear complex with formula of [Cu₂(heap)](bipy)(ClO₄)₂, where H₂heap and bipy are N,N′-bis(N-hydroxyethylaminopropyl)-oxamide and 4,4′-bipyridine, respectively, has been synthesized and characterized by elemental analyses, molar conductivity measurement, IR and electronic spectra studies, and single-crystal X-ray diffraction. The single-crystal X-ray analysis reveals that the complex has two embedded inversion centers at the mid-points of the C6–C6ⁱ bond of the oxamido group and the C7–C7ⁱⁱ bond of the 4,4′-bipyridine, respectively [symmetry code: (i) 2−x, 1−y, 1−z; (ii) =2−x, −y, 1−z]. Copper(II) atom is in a square-planar coordination geometry. The Cu···Cu separation through the oxamido birdge is 5.1430(8) ?. The bridging ligand (heap²⁻) adopts a bis-tetradentate trans conformation. A one-dimensional hydrogen bonding supramolecular structure parallel to the [2 1 0] direction is found in the crystal. The interaction of the binuclear copper(II) complex with herring sperm DNA (HS-DNA) was investigated by using absorption and emission spectra, electrochemical techniques and viscometry. The results suggest that the binuclear copper(II) complex interacts with HS-DNA by electrostatic interaction with intrinsic binding constant of 1.54 × 10⁴ M⁻¹.     

Dinuclear Ir(III) Complex with an Unusual η<Superscript>1</Superscript>:η<Superscript>3</Superscript>-allylic Bridging Ligand from the Double C–H Activation of 2,5-Dimethylthiophene

Abstract  

The unique dinuclear Ir(III) complex (Cp*IrCl)(μ-H)[μ-(η¹:η³-C₆H₆S)](IrCp*) (1) has been synthesized and characterized by NMR spectroscopy (¹H and ¹³C), elemental analysis, and single crystal X-ray diffraction. It is the first structurally determined complex in which an activated thiophene ligand displays an η³-allylic interaction. 1 appears to form from successive C-H bond activations of 2,5-dimethylthiophene, resulting in its bridging the two iridium centers. The η³-allylic interaction occurs with one of the Ir centers and has Ir–C_thio bond lengths ranging from 2.133(5)-2.207(5) ?; the C–C double bond involved in the interaction has a bond length of 1.438(7) ? compared to 1.348(8) ? for the uncoordinated C–C double bond. The 3-carbon of the thiophene ring bridges both iridium centers with bond lengths of 2.036(5) ? and 2.208(5) ?. 1 crystallizes in space group P−1 with cell constants a = 8.6303(6) ?, b = 9.0153(6) ?, c = 18.1089(12) ?, α = 84.728(1)°, β = 87.534(1)°, γ = 64.373(1)°, and Z = 2. The structure was solved by direct methods and refined to R = 0.0363 (F ² > 2σ(F ²)) and wR = 0.0851 (F ²). The NMR data indicate the solution state structure is consistent with the solid state structure.     

Synthesis,Spectroscopic Studies and X-ray Analysis of (<Emphasis Type="Italic">E</Emphasis>)-2-(2-Fluorophenyl)-3-(6-Nitrobenzo[d][1,3]dioxol-5-yl) Acrylic Acid

Abstract  

In the solid-state structure of the title compound, C₁₆H₁₀FNO₆, the configuration about the C=C double bond is E. The compound crystallized in the triclinic system, having space group P-1 with unit cell dimensions a = 5.829(10) ?, b = 8.801(16) ?, c = 13.543(3) ?, α = 87.753(15)°, β = 81.945(15)°, γ = 86.342(14)°. The structure of the molecule is V-shaped and in the crystal the molecules are linked to form inversion dimers connected by pairs of C–H···O hydrogen bonds.     

The X-ray Structures of Sulfones

Abstract  

The X-rays structures of diphenyl sulfone 1, bis(3-aminophenyl) sulfone 2, bis(4-nitrophenyl) sulfone 3, 2-nitrophenylphenyl sulfone 4, benzylphenzyl sulfone 5, 4-nitrobenzylphenyl sulfone 6, 4-methylphenylbenzyl sulfone 7, dibenzyl sulfone 8, benzylisopropyl sulfone 9, and methylacetate,ethyl sulfone 10, are reported. B3PW91 DFT calculations were performed on selected sulfones for comparison. The S = O distances in these compounds range from 1.392(5) to 1.463(3) Å and S–C bond distances range from 1.743(7) to 1.790(3) Å. The C–S–C bond angles vary from 101.1(3)° to 106.80(14)° and the O–S–O bond angles vary from 116.7(2)° to 120.61(8)°. Using data obtained here and comparison with published structural data no evidence was found for para substituents on aryl groups influencing S–O bond distances, however, small changes on S–C bond distances were noted. Additionally, if the sulfur is flanked by an alkyl group the S–C distance is slightly larger than when it is flanked by an aryl group. Most of the sulfone compounds studied here display intermolecular soft hydrogen bonding interactions which influence their solid state packing. Furthermore, in dialkyl sulfone compounds these interactions appear to be strong enough to overcome conformational barriers calculated to be ca. 6 kJ mol⁻¹.     

Rapid Eco-Friendly Synthesis and Structure of 3-Hydroxy-3-nitromethyl-1,3-dihydro-indol-2-one

Abstract  

3-Hydroxy-3-nitromethyl-1,3-dihydro-indol-2-one was synthesized from isatin by Henry reaction using an eco-friendly method and characterized by NMR and MS. The crystal structure was determined from single-crystal X-ray diffraction data. It crystallizes in the orthorhombic space group, Pbca, with unit cell dimensions a = 10.515 (2) Å, b = 7.3736 (14) Å, and c = 23.261 (4) Å. The two rings are coplanar and the angle between hydroxyl group and nitromethyl group is 109.07(9)°. In the crystal structure, intermolecular N–H···O and O–H···O hydrogen bonds are responsible for the formation of a 3-dimensional network. No intramolecular hydrogen bond exists.     

Synthesis, Structural Characterization and Spectroscopic Properties of 1,2-Bis[4-(3,5-dimethyl-1H-pyrazol-1-yl)-2-oxobutyl]benzene

Abstract  

The crystal structure of the title compound C₂₂H₃₀N₄O₂·H₂O (L), has been determined using X-ray diffraction at 293 K. The crystal of 1,2-bis[4-(3,5-dimethyl-1H-pyrazol-1-yl)-2-oxobutyl]benzene is in triclinic crystal system with space group P(−1) (Z = 2), lattice parameters a = 8.225(6) ?, b = 10.967(6) ?, c = 12.903(6) ?, V = 1119.1(11) ?³. Analyses of single crystals of L, crystallized from dichloromethane/diethyl ether (1:1), revealed that the molecules are arranged in couples, which adopt a pseudo chair conformation, by means of intermolecular O–H···N hydrogen bonding interactions. Moreover, the extended structure revealed a 1D chain caused by several C–H···N intermolecular interactions.     

Crystal Structure of (E)-2,3-Dihydro-2-(R-Phenylacylidene)-1,3,3-Trimethyl-1H-Indole (R?=?4-CN, 4-Cl)

Abstract  

Two new 1,3,3-trimethyl-2-methylene-2,3-dyhidro-1H-indole derivatives, (E)-2,3-dihydro-2-(4-cyanophenylacylidene)-1,3,3-trimethyl-1H-indole, (I), and (E)-2,3-dihydro-2-(4-chlorophenylacylidene)-1,3,3-trimethyl-1H-indole, (II), have been synthesized and their crystal structure determined by single crystal X-ray diffraction. (I), C₂₀H₁₈N₂O, crystallizes in a monoclinic space group, P2₁/c, with unit cell parameters a = 9.882 (3), b = 15.614(4), c = 11.181(3) ?, β = 106.691(4)°, Z = 4. (II), C₁₉H₁₈Cl N O, crystallizes in a monoclinic space group, P2₁/n, with unit cell parameters a = 14.6722(19), b = 7.2597(9), c = 16.304(2) ?, β = 111.249 (2)°, Z = 4. The molecules consist of a enaminoketone group formed by a Fischer base 1,3,3-trimethyl-2-methylene-2,3-dihydro-1H-indole bonded, at the exocyclic electron-rich β-carbon atom of the indole moiety, with the benzoyl chloride derivatives substituted at para-positions with cyano and chloro groups. The molecules adopt a s-cis conformation with respect to the C=O bond towards the C=C bond, and a E configuration about the latter indole exocyclic alkene C–C bond. Intermolecular arrangement of the crystals show, for (I) an antiparallel stacking mode favored by the formation of weak C–H···π interactions involving the phenyl ring attached to the carbonyl group and the phenyl of the indole fragment in a head-to-tail mode, whereas, (II) present an weak C–H···Hal interaction.     

Synthesis,Spectroscopic Studies and Structure of 2-[(Benzo[<Emphasis Type="Italic">d</Emphasis>]thiazol-2-ylamino)methyl]phenol

Abstract  

Schiff base (E)-2-[(benzo[d]thiazol-2-ylimino)methyl]phenol (1) has been synthesized from the reaction of 2-hydroxy-benzaldehyde with 2-aminobenzothiazole. The 2-[(benzo[d]thiazol-2-ylamino)methyl]phenol (2) was prepared reduction of the Schiff base 1 with sodium borohydride. The compounds 1 and 2 have been characterized by elemental analysis, FT-IR, ¹H-NMR, ¹³C-NMR and UV–visible spectroscopic techniques. The structure of the compound 2 has also been examined crystallographically. The compound 2 crystallizes in the monoclinic space group P2/c. The unit cell parameters were found as a = 10.017(1), b = 11.725(1), c = 10.341(1) ?, V = 1208.1(1) ?³, D _x = 1.409 g cm⁻³ and Z = 4. The crystal structure was solved by direct methods and refined by the full-matrix least squares method and found as R ₁ = 0.0308 and wR ₂ = 0.0818 for 2032 for the observed reflections [I > 2σ(I)].