The Previously Unclassified Smectic Phases of Bis-(4′-n-Heptyloxybenzylidene)-1, 4–Phenylenediamine (HEPTOBPD)

Re-examination of the bis-(4′-n-alkoxy-benzylidene)-1,4–phenylenediamines, particularly the heptyloxy homologue, by optical microscopy and differential scanning calorimetry has confirmed the existence of two hitherto unclassified smectic phases, which are now assigned the code letters J and K (S_J andS_k     

The Mesogenic Behavior of Isomeric and Nonisomeric Series of Novel Azoesters. 4-(4′-n-Alkoxy Benzoyloxy) Phenylazo-2″-Bromobenzenes

A novel homologous series: 4-(4′-n-alkoxy benzoyloxy) phenylazo-2^″-bromobenzenes is synthesized and studied with a view to understanding and establishing the effects of molecular structure on mesogenic behavior in a series. The mesogenic property commences from fifth homologue to the last homologue. The transition temperatures of the series are relatively low ranging between 68°C and 143°C. The mesogenic range varies between 6°C and 22°C. The novel azoester series is nematogenic without exhibition of any smectogenic property and an average thermal stability of 89.4°C. The mesogenic behavior of the novel series is compared with structurally similar isomeric/nonisomeric other known series.     

Molecular structure and absolute configuration of (−)-(1R, 2S, 6R, 7S, 2′S)-5-(2′-hydroxymethylpyrrolidin-1′-yl)-endo-tricyclo[5.2.1.02,6]deca-4,8-dien-3-one

The crystal and molecular structure of (–)-(1R, 2S, 6R, 7S, 2S)-5-(2-hydroxymethyl-pyrrolidin-1-yl)-endo-tricyclo[5.2.1.0^2,6]deca-4,8-dien-3-one is described. Knowing the absolute configuration of the prolinol moiety (S) the X-ray diffraction study established the absolute configuration of the title compound. The structure was refined to R ₁ = 0.0322 for 1237 reflections (with I > 2(I)). Crystal data: C₁₅H₁₉NO₂, monoclinic, space group P2₁, a = 6.0757(4), b = 11.3473(5), c = 9.5114(7)Å, = 104.686(6)°, V = 634.32(7)ų, and Z = 2.     

Crystal and Molecular Structure Studies of 1′-Benzyl-8-(4-fluorobenzyl)-8-azaspiro[bicyclo-[3.2.1]octane-3,4′-imidazolodine]-2′,5′-dione

Abstract  

The title compound, C₂₃H₂₃FN₃O₂ has been synthesized and the structure was investigated by X-ray diffraction studies. The compound crystallizes in the triclinic crystal class in the space group P[`1]P\overline{1} with cell parameters a = 9.345(2) ?, b = 10.940(3) ?, c = 11.986(4) ?, α = 72.349(6)°, β = 68.106(18)°, γ = 66.867(5)°, Z = 2 and V = 1027.8(5) ?³. The hydantoin ring adopts a planar conformation and is affected by the π conjugation. The pyrrolidine and piperidine rings in the bicyclo octane moiety adopt envelope and chair conformations respectively. The structure exhibits both inter and intramolecular hydrogen bonds of the type N–H···O, C–H···O and C–H···N. One of the oxygen atoms attached to the hydantoin ring simultaneously accepts two hydrogen bonds to form a three centered hydrogen bonding pattern.     

Synthesis and Structural Characterization of [2-(2-1H-Imidazoly)-1H-imidazolium nitrate] and [2-(2-1H-Imidazoly)-2H-imidazolium phthalyl glycinate] Based on the 2,2′-bi-1H-Imidazole Molecule

Abstract  

Two new compounds (H₃biim)(NO₃)(1) and (H₄biim)(phthgly)₂ (2) (H₂biim=biimidazole; Hphthgly=N-phthaloylglycine) have been synthesized and characterized by luminescence and single crystal X-ray diffraction study. Compound 1 crystallizes in the monoclinic space group C2/c, where a = 14.8078(15), b = 5.9233(6), c = 20.028(2) ?, β = 92.7910(10)°, V = 1754.6(3) ?³ and Z = 8. Compound 2 crystallizes in the monoclinic space group P2(1)/n, where a = 15.3775(14), b = 5.3200(6), c = 6.4689(18)?, β = 115.418(2)° V = 1216.9(2)?³ and Z = 4. In 1, the N–H groups of H₃biim⁺ and the oxygen atoms of NO₃ ⁻ are linked by hydrogen bonds leading to H₃biim⁺(N,N)–R₂²(10) and N–H···O interactions forming infinite 1D helical chains along the b-axis. Compound 2 consists of a planar diprotonated biimidazole moiety and two phthgly anions which connect to the dication by hydrogen bonds phthgly⁻(O,O)–R₂²(9).     

Chain Ordering and Sm-N Transition in Different Members of the Homologous Series 4-(4′- n-AIkoxy Benzylideneamino) Biphenyls

Our extension of Marcelja's theory of nematic-isotropic transition to the smectic A phase is used to calculate the smectic A-nematic (Sm-N) transition temperatures for the homologous series 4–(4′- n-alkoxy benzylideneamino) biphenyls. In a mean field calculation, explicit inclusion of the conformational energies of the alkyl chain of a molecule in the partition function shows an even-odd effect generally observed in experiments on Sm-N transitions. It is found that the members of this series showing the smectic phase will have first order Sm-N transitions and the transition entropies for individual members are calculated.     

Crystal Structure of 3′-(4-Methoxyphenyl)-2-Phenyl-4′-(4-Ethoxyphenyl)-1,2-Dihydro-4H,4′H-Spiro [Isoquinoline-3,5′-Isoxazol]-4-One

The title compound, 3′-(4-methoxyphenyl)-2-phenyl-4′-(4-ethoxyphenyl)-1,2-dihydro-4H,4′H-spiro[isoquinoline-3,5′-isoxazol]-4-one was synthesized from the reaction of dipolarophile with p-methoxybenzadoxime in the presence of sodium hypochlorite in chloroform solution. The structure of the synthesized compound was determined by IR, ¹H NMR, mass spectroscopic data, ¹³C NMR spectroscopy, elemental analysis and X-ray crystallography. The structure was solved in monoclinic, space group C2/c with a = 21.941 (4), b = 17.233 (3), c = 15.404 (3) Å, β = 122.193 (2), V = 4928.9 (16) Å³, Z = 8 and with R_int = 0.154. The geometry of the title compound showed that the piperidine ring adopts a half-chair conformation. In the crystal structure, molecules are linked by C–H···O and C–H···N contacts. Weak C–H···π interactions plays an important role in stabilizing the supramolecular structure.     

Synthesis and Evaluation of Liquid Crystal Behavior of a Novel Homologous Series: 4-(4′-n-Alkoxy benzoyloxy) Phenylazo-2″, 6″-dimethylbenzenes

A novel homologous series entitled 4-(4′-n-alkoxy benzoyloxy) phenyl azo 2^″, 6^″-dimethyl benzenes consisting of 12 members is reported. Liquid crystal behavior as a nematogenic mesophase commences from the pentyloxy homologue monotropically and then continues enantiotropically until the last hexadecyloxy homologue without exhibition of any smectogenic behavior. An odd-even effect is observed for nematic-isotropic transition curve of the phase diagram. The textures of the nematic mesophase are of the threaded or Schlieren type. Analytical and spectral data support the molecular structure of the homologues. Transition temperatures of the novel homologues were determined by an optical polarizing microscopy. Liquid crystal properties of a novel homologous series are compared with other known homologous series. The average thermal stability for the nematic phase is 77.1°C.     

7-Hexyloxy-3-[4’-(3-methylbutyloxy) phenyl]-4H-1-benzopyran-4-one: Study of Smectic behaviour and UV absorption profile

The intermolecular interaction energies between a pair of 7-Hexyloxy-3-[4’-(3-methylbutyloxy) phenyl]-4H-1-benzopyran-4-one (HMBPB) molecules have been estimated with respect to translational and orientational motions. The complete neglect differential overlap (CNDO/S) method has been employed to calculate the net atomic charge and atomic dipole moment components at each atomic center. The modified Rayleigh-Schrodinger perturbation theory along with multicentered-multipole expansion method has been employed to evaluate the long-range intermolecular interactions, while a ‘6-exp’ potential function has been assumed for short-range interactions. The total interaction energy values obtained through these computations have been used to calculate the probability of each configuration at room temperature (300K), and isotropic-smectic transition temperature (412.6K). Molecular arrangements inside a bulk of materials and smectic behavior of the compound in terms of their relative order have been discussed. Translational and rotational rigidity of the molecule has been analyzed to understand the smectic behaviour. The UV absorption profile has been estimated using CNDO/S, and INDO/S methods.     

Synthesis and crystal structures of 4,4′-bipyridinium and 2,2′-bipyridinium pentachloro complexes containing the polynuclear anions [Bi2Cl10]4− and [Bi4Cl20]8−

The compounds 4,4-bipyridinium(2+) pentachloro-bismuthate(III) (1), [4,4-(C₁₀H₈N₂)BiCl₅] and 2,2-bipyridinium(2+) pentachloro-bismuthate(III) (2), [2,2-(C₁₀H₈N₂)Bi₂Cl₁₀] have been obtained by reacting bismuthate oxide and 4,4-bipyridine or 2,2-bipyridine in HCl acid medium. They have been characterized by single crystal X-ray analysis. (1) crystallizes in the triclinic space group with a = 9.776(2), b = 11.009(3),c = 8.346(1) Å, = 101.58(2), = 98.63(2), and = 112.86(2)°. (2) crystallizes in the monoclinic space group P2₁/c with a = 14.239(2), b = 14.226(2), c = 16.275(3) Å, and = 110.15(2)°. The crystal structure of (1) consists of 4,4-bipyridinium(2+) cations interacting through hydrogen bonding with [Bi₂Cl₁₀]^2– dimers giving rise to endless double chains, while that of (2) is formed by 2,2-bipyridinium(2+) cations and [Bi₄Cl₂₀]^8– tetramers extensively interacting through hydrogen bonding. The different polynuclearity of the anions seems related to the different directions along which each cation can form hydrogen bond interactions.     

Crystal structure of 2-(1-o-xylen-4′-yl-2-hydroxy-5-oxo-benzo[c]pyrroline) carboxylic acid, C17H15NO4

The title compound crystallizes in the space group P2₁/c, with a = 8.555(2), b = 22.109(2), c = 16.768(2) Å, and = 90.25(2)°, with two independent molecules in the asymmetric unit, dissimilar only for the orientation of the xylenyl group. There is no conjugation between the pyrroline ring and the xylenyl group. The molecules in the asymmetric unit are enantiomers, thus constituting a racemic dimer. The molecules are linked in chains by hydrogen bonds.     

Synthesis and crystal structure of 3-ammoniumphenyl sulfone selenate, 3-aminophenyl sulfone [C12H14N2O2S]SeO4 · [C12H12N2O2S]

The crystal structure of [C₁₂H₁₄N₂O₂S]SeO₄ · [C₁₂H₁₂N₂O₂S] was determined by X-ray diffraction on single crystal. Crystals are orthorhombic, space group Pbca, with cell parameters a = 11.545 (1), b = 8.143 (1), c = 55.783(1)Å, V = 5244.2 (8)ų and Z = 8. The structure can be described as organic layers built by [C₁₂H₁₄N₂O₂S]²⁺ cations and [C₁₂H₁₂N₂O₂S] molecules, parallel to ab plane, between which the inorganic groups SeO ₄ ^2? are inserted. In this atomic arrangement, H-bonds between the different species play an important role in the three-dimensional network cohesion.     

Synthesis and Mesomorphic Properties of the Homologous Series of Di-(4′- n-alkylphenyl)- trans-cyclohexane-1,4-dicarboxylates

The homologous series of di-(4′- n-alkylphenyl)- trans-cyclohexane-1,4-dicarboxylates in which the alkyl group is C₁-C₁₂ has been prepared by esterification of trans-1,4-cyclo-hexanedicarboxylic acid or dicarbonyl chloride with 4-alkylphenols. Mesomorphic properties and phase transitions as determined by hot-stage polarizing microscopy and DSC are discussed in relationship to various structural features. Comparisons of these properties with those for the corresponding alkoxy series and the analogous terephthalic acid diesters are also presented and discussed.     

Synthesis and crystal structure of (S, S, S, S)-N, N′-bis[N-(P-toluenesulfonamido)-1,2-diphenylethyl]ethylenediamine

(S, S, S, S)-N,N′-bis[N-(p-toluenesulfonamido)-1,2-diphenylethyl] ethylenediamine (C₄₄H₄₆N₄O₄S₂), has been synthesized and structurally characterized by elemental analysis, ¹H-NMR, MS, IR and single-crystal X-ray diffraction. The title compound contains four chiral centers with C atoms in S configuration. Molecules are connected to one another by hydrogen bonds between sulfonamide nitrogen and sulfonyl oxygen to form chains alone a axis.     

New Series of Biforked Mesogens Derived from 3,4-Dialkoxycinnamic Acid and 3-(3′4′-Dialkoxyphenyl)Propanoic Acid

Four series of biforked or polycatenar mesogens derived from 3,4-dialkoxycinnamic or 3-(3′,4′-dialkoxyphenyl)propanoic acids are described. These derivatives exhibit an extremely complex polymorphism including lamellar and columnar mesophases as well as nematic and cubic and some unidentified phases. X-Ray measurements have given the first evidence for a thermotropic rhombohedral mesophase. The relationships between the polymorphism and molecular structure are discussed.     

Crystal structure of syn-1-acetyl-9′aH-8′- methoxyspiro[indole-3,2′-oxeto[3′,2′:4,5]furo[3,2-g][1] benzopyran]2,6′-dione

The crystal structure of syn-1-acetyl-9a-hydro-8-methoxyspiro[3H-indole-3,2(2aH) oxeto[3,2-g]furo[3,2-g]benzo[ b]pyran-2,6-dione 1 was determined by X-ray diffraction analysis. It possesses P2(1)/c space group symmetry, with a = 12.391(3), b = 15.035(3), c = 9.5435(19) Å, = 93.66(3), and D _calc. = 1.517 Mg/m³ for Z = 4.     

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.     

A structural model for a new class of conformationally constrained retinoid: (2Z,4E)-4-[3′,4′-dihydro-1′(2′H)-naphthalene-1′-ylidene]-2-butenoic acid

Racemic (2Z,4E)-4-[3′,4′-dihydro-1′(2′H)-naphthalene-1′-ylidene]-2-butenoic acid (1) is a polyene chain-shortened analog of (9Z)-retinoic acid (3) which uses a tetrahydronaphthyl ring to conformationally constrain the C6-C7 single bond (retinoic acid numbering). The structure of (1) was obtained to determine the effects of the tetrahydronaphthyl ring on the ring to polyene chain conformation as compared to a published crystal structure for (9Z)-retinal (2). The results reveal significant differences between the solid state structures of (1) and (2), particularly for torsion angles about C6, C7 and C8, C9. The title compound crystallizes in the centrosymmetric monoclinic space groupP2₁/n withZ=4. (Cell dimensions:a=10.863(2) Å,b=7.637(2) Å,c=15.781(3) and β=106.11(3)°.) The structure was refined toR=3.88% for those 1132 unique data with |F _o|>6σ(F _o). In the crystal structure, the molecules adopt a hydrogen bonded dimeric structure.