Crystal and molecular structure of the spin-crossover complex bis(pyridine) [N,N′-ethylenebis (3-carboxysalicylaldimine)] cobalt (II)

The average structure of the title compound, Co(H₂fsa₂en)(py)₂, which has been shown previously to exhibit a thermally induced high-spin low-spin crossover, has been investigated by single-crystal X-ray diffraction. This structure has been solved in the monoclinic space groupC2/c (No. 15), with cell dimensionsa=16.641(5),b=9.496(4),c=16.329(6) Å, and=95.47(3)°;V=2569(3) ų,M _r =571.46,Z=4,D _x =1.478 mg m^–3; MoK radiation (graphite crystal monochromator),=0.71073 Å,(MoK)=7.138 cm^–1;T=295 K andR=0.081 for 681 observed [I>3(I)] independent reflections. The cobalt(II) ion resides on a twofold axis in an elongated octahedral environment, the length of the apical bond (formed with pyridine) being 2.262(12) Å and the mean length of the equatorial bonds (formed with the Schiff base) 2.079(12) Å. These values are consistent with the magnetic behavior, which suggested a distorted surrounding for the metal atom. The packing is essentially governed by the parallelism of the salicylaldimine ligands. The two pyridine rings of the molecule are twisted by ~98° on each side of the basal plane; they are probably affected by orientational disorder or, if ordered, they might be described in a superstructure not yet established.     

Structure of lithium (picrate) (2,2′-bipyridyl)

The title compound C₁₆H₁₀N₅O₇Li is triclinic, witha=14.51(1),b=6.90(2),c=9.10(1) Å,=101.5(1),=67.1(2), =105.6°(1),Z=2 and space groupP¯1. Data were measured by photographic methods. The structure was solved by direct methods, and refined by full matrix least-squares. The refinement, based on 1337 reflections, gave the rather highR value of 0.11 because of poor quality data. The complex is dimeric. The coordination around the cation is distorted square-pyramidal. Two coordination sites are occupied by the nitrogen atoms of the bipyridyl ligand, two by the phenolic oxygen and oxygen ofo-nitro group, and the fifth coordination site is occupied by the phenolic oxygen belonging to the symmetry-related molecule (1–x,–y,1–z). Both oxygens act as bridges to form the dimer. The bridging is unsymmetrical, with Li-O (phenolic)=1.84(2) Å and Li¹-O (phenolic)=2.16(2) Å (whereI=1–x,–y, 1–Z).     

The crystal and molecular structure of spiro[1-(S)-Br-3-(S)-H-4-(R)-l-(1′ R,2′ S,5′R)-menthyloxy-5-oxo-6-oxa-bicyclo[3.1.0]hexane-2,3′-(R)-(4′-(R)-diphenylmethoxy-5′-l-(1′ R,2′ S,5′ R)-menthyloxy-butyrolactone)]

Crystal structure of C₄₁H₅₃O₇Br has been determined by single-crystal X-ray diffraction. The compound crystalline in the orthorhombic space group P2₁2₁2₁, with a = 11.264(2), b = 12.058(2), c = 29.337(6) Å, Z = 4. The bond angles of cyclopropane moiety in the molecule are approximate to 60° and agree with theoretic values of the internal angles in a cyclopropane, and two chiral menthyloxy groups are located above and under the whole chiral molecule, respectively. The configuration of the pentacyclic lactone is shown as envelope form.     

Structural study of nitrovinylindoles: (I) 2-methyl-3-(2′-methyl-2′-nitrovinyl)indole and (II) 3-(2′-nitrovinyl)indole

Compound (I) is 2-methyl-3-(2-methyl-2-nitrovinyl)indole, C₁₂H₁₂N₂O₂,M _r=216.24, monoclinic,P2₁/n,a=16.710(1),b=7.627(1),c=17.646(1) Å,=104.8(1)°,V=2174.7(1) ų,Z=8.D _x=1.321 g cm^–3, MoK, =0.71073 Å,=0.858 cm^–1,F(OOO)=912, room temperature,R=0.061 for 1956 observed reflections. Compound (II) is 3-(2-nitrovinyl)indole, C₁₀H₈N₂O₂,M _r=188.18, monoclinic,P2₁/n,a=10.178(1),b=10.608(1),c=8.411(1) Å,=105.5(2)°,V=875.0(1) ų,Z=4,D _x=1.4284 g cm^–3, CuK, =1.5418 Å,=8.068 cm^–1,F(000)=392, room temperature,R=0.040 for 1330 observed reflections. Compounds (I) and (II) have a similar geometry, the only significant difference lying in the rotation of the nitrovinyl chain. This feature could be responsible for the difference in biological activity. In both compounds, the molecules are associated, forming charge-transfer complexes.     

Structure of 2-(2′-bromo-5′-nitrostyryl)benzothiazole

The title compound C₁₅H₉BrN₂O₂S (brnsb) is monoclinic, witha=7.730(2),b=26.847(5),c=7.773(2) Å,=117.48(1)°,V=1431(1) ų,Z=4,D _x=1.677,(MoK)=29.9 cm^–1,F(000)=720,T=298K in space groupP2₁/c. The structure was solved by heavy atom and Fourier methods and refined toR=0.034 for 1776 unique observed reflections. The molecule is nearly planar, with a dihedral angle of only 3.8(1.1)° between the benzothiazole and phenyl rings. The C-S-C angle in the thiazole ring is 89.0°, while the C-N-C angle in that ring is 111.5(3)°.     

Structure of (2,2′-bipyridine)lead(II) saccharinate monohydrate

The structure of (2,2-bipyridine)lead(II) saccharinate monohydrate has been investigated by X-ray diffraction. The compound crystallizes in the monoclinic space group P2 ₁/n with a = 22.903(7), b = 12.608(3), c = 8.682(2) Å, = 96.76(3)°, and Z = 4. The structure consists of Pb²⁺ cations, 2,2-bipyridine ligands, saccharinato anions and water molecules. The Pb²⁺ cation is surrounded by two O atoms and four N atoms. The two saccharinato ions are nonequivalent. The water molecule forms hydrogen bonds of O_W···O_CO [2.810(16) Å] and O_W···O_SO2 [2.893(16) Å] type.     

Structures of nitrato-(2-hydroxybenzaldehydo) (2,2′-bipyridyl)copper and nitrato-(2-hydroxy-5-nitrobenzaldehydo)(2,2′-bipyridyl)copper

Nitrato-(2-hydroxy-5-nitrobenzaldehydo)(2,2′-bipyridyl)copper (I) and nitrato-(2-hydroxybenzaldehydo)(2,2′-bipyridyl)copper (II) were synthesized and characterized by X-ray diffraction. The coordination polyhedron of the central copper atom in complex I can be described as a distorted tetragonal pyramid whose base is formed by the phenol and carbonyl oxygen atoms of the monodeprotonated 2-hydroxy-5nitrobenzaldehyde molecule and the nitrogen atoms of the 2,2′-bipyridyl ligand and whose apex is occupied by the oxygen atom of the nitrato group. In the crystal structure, complexes I are linked by the acido ligands and the NO₂ groups of the aldehyde molecule into infinite chains. In complex II, the central copper atom is coordinated by 2-hydroxybenzaldehyde, 2,2′-bipyridyl, and the nitrato group, resulting in the formation of centrosymmetric dimers. The coordination polyhedron of the central copper atom can be described as a bipyramid (4 + 1 + 1) with the same base as in complex I. The axial vertices of the bipyramid are occupied by the oxygen atom of the nitrato group and the bridging phenol oxygen atom of the adjacent complex related to the initial complex by a center of symmetry. In the crystal structure, complexes II are hydrogen bonded into infinite chains.     

Molecular and crystal structure of two nickel(II) 1,2-dithiooxalato-S,S′ complexes using 1-(Rbenzyl)pyridinium cation (R = 4′-bromo-2′-fluoro or 4′-bromo)

[BrFPy]₂[Ni(dto)₂] (1) and [BrPy]₂[Ni(dto)₂] (2) complexes have been prepared by reaction of Na₂[Ni(S₂C₂O₂)₂] and the corresponding 1-(Rbenzyl)pyridinium bromide salt (R₁ = 4-bromo-2-fluoro, R₂ = 4-bromo). The crystallographic data for 1: monoclinic P2₁/c, a = 14.2192(1) Å, b = 14.2533(4) Å, c = 15.6535(3) Å, = 96.463(1)°, V = 3152.34(11) ų, Z = 4. Two cations, [Br₁F₁Py]⁺ and [Br₂F₂Py]⁺, both adopt a conformation where both the aromatic rings are twisted to the corresponding N(1)–C(10)–C(11) or N(2)–C(22)–C(23) reference plane. Data for 2: triclinic , a = 9.4042(3) Å, b = 9.6814(4) Å, c = 10.3357(4) Å, = 80.155(1)°, = 65.245(1)°, = 64.259(1)°, V = 769.68(5) ų, Z = 1. The [Ni(dto)₂]^2– anion exhibits a quasi-planar structure in both complexes. An extensive hydrogen bond network of C–H O is clearly observed in 1 and 2, and two complexes show similar crystal packing.     

Crystal structures of bis(cyanido)bis(N,N′-diethylthiourea-κS) mercury(II) and bis(cyanido)bis(N,N′-dipropylthiourea-κS) mercury(II)

Two mercury(II) complexes containing cyanide and, N,N′-diethylthiourea (detu) and N,N′-dipropylthiourea (dprtu) ligands, [(detu)₂Hg(CN)₂] (1) and [(dprtu)₂Hg(CN)₂] (2), respectively, have been prepared and characterized by X-ray crystallography. In the both complexes Hg atom lies on a 2-fold rotation axis, and is coordinated to the sulfur atoms of two thiourea ligands and to two cyanide carbon atoms. Both have a distorted tetrahedral environment with bond angles about the Hg atoms in the range of 93.41(4)°–146.75(19)°. In the crystal structures symmetry related molecules are linked via N-H-N hydrogen bonds resulting in the formation of a two-dimensional network in 1, while in 2 a double stranded one-dimensional chain is formed.     

Bis(2,6-(2′,6′-diisoproylanil)diformyl-4-chloro-phenolate) nickel(II)

Bis(2,6-(2,6-diisoproylanil)diformyl-4-chloro-phenolate) nickel(II) was prepared by the reaction of 2,6-(2,6-diisoproylanil)diformyl-4-chloro-phenol with nickel chloride. The title complex crystallized in P2₁/c, with cell dimensions a = 9.962(2) Å, b = 12.087(3) Å, c = 24.445(6) Å, and = 97.032(5), giving a volume of 2921.4(13) ų. The bis(2,6-(2,6-diisoproylanil)diformyl-4-chloro-phenolate) nickel(II) adapts an ideal parallelogram, in which the Ni atom is coordinated with two phenolic oxygen atoms [O(1), O(1A)] and two imino nitrogen atoms [N(1), N(1A)].     

Structure of 1-ethyl-2-(2′-chloro-4′-nitrostyryl)benzimidazole

The title compound C₁₇H₁₄ClN₃O₂ (et-4-nsbiz) is monoclinic, witha=12.240(2),b=12.144(4),c=10.544(4)Å,=100.09(2)°,V=1543(1)ų,Z=4,D _x =1.411 g cm^–3, (MoK)=0.71073Å,=2.57 cm^–1,F(000)=680,M _r =327.77,T=298K. The structure was solved by heavy atom and Fourier methods and refined toR=0.049 for 1503 unique observed reflections in space groupP2₁/c. Except for the ethyl group, the molecule is almost planar, with a dihedral angle of 9.5(5)° between the benzimidazole and phenyl rings. The dihedral angle between the ethyl group and the benzimidazole ring to which it is attached is 91.5(2)°.     

Synthesis and crystal structure of a new organic compound: Bis(4,4′-diaminodiphenylmethane) (4,4′-diammoniodiphenylmethane) dichloride monohydrate

A new organic compound with the formula C₃₉H₄₆Cl₂N₆O was synthesized from aqueous solution of 4,4′-diaminodiphenylmethane and hydrochloric acid at room temperature. This compound crystallizes in the monoclinic space group C2: a = 25.6525(16), b = 5.7107(3), c = 13.7777(8) Å, β = 118.862(2)°, V = 1767.64(22) ų and Z = 2, giving D _x = 1.288 g cm^?3. The refinement converged to R ₁ = 0.027 and wR ₂ = 0.0649. The structural arrangement can be described as infinite layers parallel to bc plane. In these layers cations and non protonated molecules are linked with N-H...N hydrogen bonds building [C₃₉H₄₄N₆]²⁺ organic clusters. These clusters, in turn, are linked by N-H...Cl and O-H...Cl hydrogen bonds.     

Synthesis and crystal structure of 1-(1′,3′-dimethyl-5′-chloropyrazol-4′-carbonyl′-3-(2′-chlorophenyl)-5-amino-4-cyanopyrazole

The title compound 1-(1,3-dimethyl-5-chloropyrazol-4-carbonyl)-3-(2-chlorophenyl)-5-amino-4-cyanopyrazole (C₁₆H₁₂Cl₂N₆O) has been synthesized and characterized by X-ray diffraction: Triclinic, space group P1, with a = 8.6712(8) Å, b = 9.5091(10) Å, c = 11.2170(11) Å = 71.531(2)°, = 84.683(2)°, = 74.099(2)° Z = 2; V = 843.7(14) ų. C(10), O(1), C(11), and N(2) atoms are coplanar with the average deviation of 0.0071 Å, which form 11.03° and 43.93° dihedral angles with pyrazole planes (I) and (II), respectively.     

Phenylmercury(II) dithiophosphates. Crystal structure of (O,O′-diethyldithiophosphate) phenylmercury(II)

The phenylmercury(II) derivatives PhHgS₂P(OR)₂ (R=C₂H₅, C₆H₁₁ and C₆H₅) have been synthesized. (O,O-diethyldithiophosphate) phenylmercury(II), C₁₀H₁₅HgO₂PS₂, crystallizes in the monoclinic space groupP2₁/c (n° 14) witha=7.330(5),b=18.085(2),c=11.552(4)Å,=105.96(5)°,V=1472.3(6)ų,Z=4,D=2.088 g.cm^–3. The mercury atom is coordinated to the phenyl carbon atom and to a ligand sulphur atom in an almost linear arrangement (C-Hg-S angle, 176.0(2)°. The ligand is almost monodentate, its second sulphur atom only being involved in a weak secondary intermolecular bond.IR and Raman studies of the other two compounds suggest the same coordination scheme. Positive ion FAB and¹³C,³¹P and¹⁹⁹Hg NMR spectra are also discussed.     

Structure of 2,2′-bis(4-cyanatophenyl)isopropylidene

The title compound is monoclinic:a=13.345(3),b=11.393(2),c=10.046(5)Å,=108.48(2)°,Z=4,P2₁/c. The structure was determined by direct methods, using MoK diffractometer data, and refined by full-matrix least squares toR=0.045 for 1463 reflections. The structure shows a central tetrahedral carbon atom surrounded by two methyl and two phenylcyanate groups. The geometry of the cyanate group compares well with that in 4-chloro-3,5-dimethyl-phenyl cyanate, the only example of an organic cyanate in the Cambridge Crystallographic database (V.3). The intermolecular nitrile, C-N, distances were examined for evidence of a possible dimerization interaction; no significant distances were found.     

Crystal and molecular structure of 2-(2′-chloro-5′-nitrostyryl)benzoselenazole

The title compound C₁₅H₉ClN₂O₂Se (nsbse) is orthorhombic, witha=6.823(2),b=7.860(2),c=26.349(5) Å,Z=4,D _x =1.709,(MoK)=28.3 cm^–1,F(000)=720,T=298K in space groupP2₁2₁2₁. The structure was solved by heavy atom and Fourier methods and refined toR=0.045 for 1095 unique observed reflections. The molecule is almost planar, with a dihedral angle of 4.8(2)° between the benzoselenazole and phenyl rings. The C-Se-C angle in the selenazole ring is very small, 84.6(4)°, while the C-N-C angle in that ring is 113.7(7)°.     

Mechanochromic Photoluminescent Liquid Crystals Containing 5,5′-Bis(2-phenylethynyl)-2,2′-bithiophene

5,5′-Bis(2-phenylethynyl)-2,2′-bithiophene derivative 1 containing dendritic moieties linked through amide groups was synthesized. Compound 1 exhibits a rectangular columnar phase on slow cooling from the isotropic liquid. In contrast, a cubic phase is formed as a metastable liquid-crystalline phase by rapid cooling of the isotropic melt. Mechanical shearing induces a cubic–columnar phase transition, accompanied by the change of a photoluminescent color from yellow-green to green. The infrared spectra of 1 suggest that the mechanical stimuli can induce the partial dissociation of the hydrogen bond. This may lead to more disordering of the π-stacks of chromophores.     

Synthesis and Study of New Mesogens II: p-(p′-n-Alkoxycinnamoyloxy)-benzylidene p″ -anisidines (1) and p-(p′-n-Alkoxycinnamoyloxy)- benzylidene anilines (2)

Two new homologous series of liquid crystals viz. p-(p'-n-alkoxycinnamoyloxy) benzylidene p”-anisidines (1) and p-(p'-n-alkoxycinnamoyloxy) benzylidene anilines (2) comprising twenty four mesogens have been synthesized. Both are high melting series of mesomorphs. In the homologous series (1) the nematic mesophase is exhibited from the very first member; however, the first five compounds decompose at high temperatures before passing into isotropic liquid condition. Polymesomorphism is exhibited with the appearance of the smectic mesophase at the octyl derivative and remains up to the last viz. octadecyl homologue. Within polymesomorphic region the nematic mesophase is homeotropic; however, it shows a clear threaded texture where it is the only mesophase shown i. e. in the first seven members of the homologous series (1). The smectic mesophase shows focal conic fan shape texture belonging to smectic-A variety. The nematic-isotropic curve shows descending tendency as the series is ascended-a characteristic of high melting series. The smectic-nematic transition curve rises steeply and shows a levelling off tendency at the octadecyl derivative. In the homologous series (2), no decomposition occurs. The smectic mesophase commences a little early i. e. from hexyl derivative; while polymesomorphism is clearly exhibited up to the dodecyl derivative, the last two homologues are purely smectogens. The usual odd-even effect is observed in case of the nematic-isotropic curve for series (2). The smetic-nematic curve rises gradually and seems to be merging with the falling nematic-isotropic curve at the fifteenth homologue. The mesomorphic ranges in both series are quite wide; however, that of series (1) is wider than one obtained in series (2). Thermal stabilities are good and are in keeping with the molecular characteristics. The textures of the smectic and nematic mesophases are similar to that of the series (1). Both series are comparable with each other and other related series.     

Structural investigation of (Z)-N-acetyl-β(3′-pyridyl)-dehydroalanine methyl ester

The crystal and molecular structure of the methyl ester of (Z)-N-acetyl-(3-pyridyl)-dehydroalanine [methylZ-2-acetamido-3(3-pyridyl) propenoate] have been determined from three-dimensional X-ray data. Crystals are monoclinic, space groupP2₁]. The molecular [=–51.5(5),=157.0(4)°] conformation is discussed making reference to previous experimental results of analogous amino acid derivatives (in particular, ethyl (Z)-N-acetyldehydrophenylalaninate) and theoretical predictions. On the basis of He(I) and He(II) photoelectron spectra, a similar conformation is proposed for the title molecule in the vapor phase also.     

Crystal and molecular structure of aqua(2,2′-bipyridine)bis(betaine)copper(II) perchlorate monohydrate

A new monomeric copper(II) complex with 2,2-bipyridine (bpy) and betaine (bet), [Cu(byy)(bet)₂(H₂O)](ClO₄)₂ · H₂O, has been prepared and characterized by X-ray crystallography. The complex crystallizes in the triclinic space groupP-1 witha=8.859(2),b=11.191(2),c=14.850(3) Å, =91.41(1), =97.19(1), =91.97(1)°,V=1459.2(7) ų, andZ=2. The structure comprises discrete cations [Cu(bpy)(bet)₂(H₂O)]²⁺ in which the metal atom is coordinated in a distorted square-pyramidal environment by two oxygen atoms from a pair of monodentate carboxylato ligands [Cu–O=1.950(2) Å] and two nitrogen atoms of a bidentate bpy ligand [Cu–N=1.997(3)–2.005(3) Å] on the basal plane, and one aqua [Cu–O=2.267(3) Å] ligand at the apical position.