Temperature-Dependent Phase Transition Studies And Influence Of Hydrogen Bonding Interactions On The Structural And Packing Modes Of Organic Molecules In Single Crystalline State

In this research, owing to the interests in phase transitions due to hydrogen bonds, fifteen samples with crystal structures and crystal networks that are utilizing the hydrogen bonding were prepared in single crystal form for X-ray structure determination. Temperature-dependent phase transitions studies by single crystal X-ray diffraction is the main experimental method used to study the hydrogen bonding interactions in this research. Fifteen crystal structures were determined and their crystal packing modes were also studied. Only two out of fifteen samples showed phase-transition which were explained macroscopically by Landau theory

1,1′-Bicyclo­propyl-1,1′-diyl 1,1′-biphenyl-2,2′-dicarboxyl­ate

In the title compound, C20H16O4, the two benzene rings form a dihedral angle of 45.70 (4)°. In the crystal, mol­ecules are linked via C—H⋯O inter­actions into layers lying parallel to the bc plane

1-(4-Meth­oxy­phen­yl)ethane-1,2-diyl 1,1′-biphenyl-2,2′-dicarboxyl­ate

In the title mol­ecule, C23H18O5, the meth­oxy-substituted benzene ring makes dihedral angles of 65.12 (4) and 88.55 (4)° with the other two benzene rings. These two benzene rings form a dihedral angle of 45.70 (4)°. In the crystal, mol­ecules are linked into inversion dimers by pairs of weak C—H⋯O hydrogen bonds

Bis(2-amino-5-bromo­pyridinium) fumarate dihydrate

In the title compound, 2C5H6BrN2 +·C4H2O4 2−·2H2O, the complete fumarate dianion is generated by crystallographic inversion symmetry. The cation is approximately planar, with a maximum deviation of 0.036 (1) Å. In the anion, the carboxyl­ate group is twisted slightly away from the attached plane; the dihedral angle between carboxyl­ate and (E)-but-2-ene planes is 6.11 (14)°. In the crystal, the carboxyl­ate O atoms form bifurcated (N—H⋯O and C—H⋯O) and N—H⋯O hydrogen bonds with the cations. The crystal packing is stabilized by R 2 2(8) ring motifs which are generated by pairs of N—H⋯O hydrogen bonds. The crystal structure is further consolidated by water mol­ecules via O(water)—H⋯O and N—H⋯O(water) hydrogen bonds. The components are linked by these inter­actions into three-dimensional network

2-Amino-4-methyl­pyridinium 2-carb­oxy­benzoate

In the title mol­ecular salt, C6H9N2 +·C8H5O4 −, the anion is stabilized by an intra­molecular O—H⋯O hydrogen bond, which generates an S(7) ring motif. In the crystal, the cations and anions are linked to form extended chains along [001] by O—H⋯O and N—H⋯O hydrogen bonds. Adjacent chains are crosslinked via C—H⋯O inter­actions into sheets lying parallel to (100)

3-(5-Nitro-2-fur­yl)-1-phenyl­prop-2-yn-1-one

In the title compound, C13H7NO4, the 2-furyl ring is essentially planar, with a maximum deviation of 0.004 (1) Å. It is inclined at an angle of 11.69 (4)° to the benzene ring. The nitro group is slightly twisted out of the plane of the 2-furyl ring, with a dihedral angle of 5.72 (8)°. There is a short O⋯C contact of 2.8562 (8) Å (symmetry code: −x, −y, 2 − z). In the crystal packing, mol­ecules are linked via a pair of inter­molecular C—H⋯O hydrogen bonds, giving rise to an R 2 2(10) ring motif. Mol­ecules are further linked into two-dimensional networks parallel to [100] via other inter­molecular C—H⋯O hydrogen bonds. The crystal structure is consolidated by C—H⋯π inter­actions

2-[5-Methyl-2-(propan-2-yl)phen­oxy]-N′-{2-[5-methyl-2-(propan-2-yl)phen­oxy]acet­yl}acetohydrazide

The complete mol­ecule of the title compound, C24H32N2O4, is generated by a crystallographic inversion center. The 1,2-diethyl­hydrazine moiety is nearly planar, with a maximum deviation of 0.024 (1) Å, and is inclined at a dihedral angle of 54.20 (4)° with the phenyl ring. In the crystal, [001] chains are formed, with adjacent mol­ecules in the chain linked by pair of inter­molecular N—H⋯O hydrogen bonds, generating R 2 2(10) ring motifs. Inter­molecular C—H⋯O hydrogen bonds and C—H⋯π inter­actions are also observed

(E)-4-{[(3-Propyl-5-sulfanyl­idene-4,5-dihydro-1H-1,2,4-triazol-4-yl)imino]­meth­yl}-3-(p-tol­yl)-1,2,3-oxadiazol-3-ium-5-olate

The title compound, C15H16N6O2S, exists in a trans configuration with respect to the acyclic N=C bond. The 1,2,3-oxadiazol-3-ium ring makes dihedral angles of 10.59 (8) and 73.94 (8)°, respectively, with the 1,2,4-triazole and benzene rings. The mol­ecular structure is stabilized by an intra­molecular C—H⋯S hydrogen bond, which generates an S(6) ring motif. In the crystal, mol­ecules are linked into inversion dimers by pairs of inter­molecular N—H⋯S hydrogen bonds, generating eight-membered R 2 2(8) ring motifs. The dimers are further connected by C—H⋯O hydrogen bonds, forming a sheet parallel to the bc plane. The ethyl group is disordered over two sets of sites with occupancies of 0.744 (7) and 0.256 (7)

Methyl 2,2′-dimethyl-4′-[2-(methyl­sulfan­yl)eth­yl]-1,3-dioxo-2,3-dihydro-1H,4′H-spiro­[isoquinoline-4,5′-oxazole]-4′-carboxyl­ate

In the isoquinoline ring system of the title mol­ecule, C18H20N2O5S, the fused N-heterocyclic ring is distorted towards a half-boat conformation. The methyl formate moiety is disordered over two sets of sites with refined occupancies of 0.882 (5) and 0.118 (5). In the crystal, mol­ecules are linked via weak inter­molecular C—H⋯O hydrogen bonds into one-dimensional chains along [010]

2-Phenyl-N′-(2-phenyl­acet­yl)acetohydrazide

In the title compound, C16H16N2O2, the N′-acetyl­acetohydrazide group is approximately planar (r.m.s. deviation = 0.018 Å for the eight non-H atoms) and makes dihedral angles of 81.92 (6) and 65.19 (6)° with the terminal phenyl rings. The phenyl rings form a dihedral angle of 62.60 (7)°. In the crystal, mol­ecules are linked into sheets lying parallel to (001) by N—H⋯O and C—H⋯O hydrogen bonds. One O atom accepts one N—H⋯O and one C—H⋯O hydrogen bond and the other O atom accepts one N—H⋯O and two C—H⋯O hydrogen bonds. The N—H⋯O hydrogen bonds lead to R 2 2(8) loops and the C—H⋯O hydrogen bonds generate R 2 1(6) loops