Synthesis of Fluorescent 1-(3-Amino-4-(4-(tert-butyl)phenyl)-6-(p-tolyl)furo[2,3-b]pyridin-2-yl)ethan-1-one: Crystal Structure, Fluorescence Behavior, Antimicrobial and Antioxidant Studies.

Furopyridine III, namely 1-(3-amino-4-(4-(tert-butyl)phenyl)-6-(p-tolyl)furo[2,3-b]pyridin-2-yl)ethan-1-one, synthesized from 4-(4-(tert-butyl)phenyl)-2-oxo-6-(p-tolyl)-1,2-dihydropyridine-3-carbonitrile I in two steps. The title compound is characterized by NMR, MS and its X-ray structure. The molecular structure consists of planar furopyridine ring with both phenyl rings being inclined from the furopyridine scaffold to a significant different extent. There are three intramolecular hydrogen bonds within the structure. The lattice is stabilized by N-H…O, H2C-H …π and π…π intermolecular interactions leading to three-dimensional network. Compound III exhibits fluorescent properties, which are investigated. Antimicrobial potential and antioxidant activity screening studies for the title compound III and the heterocyclic derivatives, I and II, show no activity towards neither bacterial nor fungal strains, while they exhibited weak to moderate antioxidant activity compared to reference.

Synthesis, Spectral Characterization and Fluorescent Assessment of 1,3,5-Triaryl-2-pyrazoline Derivatives: Experimental and Theoretical Studies.

Two new pyrazoline derivatives, namely 5-(4-bromophenyl)-3-(5-chlorothiophen-2-yl)-1-phenyl-4,5-dihydro-1H-pyrazole (3) and 5-(4-bromophenyl)-3-(2,5-dichlorothiophen-3-yl)-1-phenyl-4,5-dihydro-1H-pyrazole (4) have been synthesized and characterized based on their spectral (IR, (1)H and (13)C NMR and MS) data and microanalysis. The fluorescence properties of 3 and 4 were studied by UV-Vis and emission spectroscopy. For compound 3, a fluorescence emission was observed in the blue region of the visible spectrum. The effect of different solvents on fluorescence was also investigated. Density Functional Theory calculations have also been performed to gain insight into geometric, electronic and spectroscopic properties of the pyrazoline derivatives. Both structures are analysed and compared in order to rationalize the different behaviour in 3 and 4.

3-Bromo-N-(3,5-di-tert-butyl-phen-yl)propanamide.

The title compound, C17H26BrNO, exhibits a small twist between the amide residue and the benzene ring [C-N-C-C torsion angle = 29.4 (5)°]. In the crystal, the amido NH group is involved in N-H⋯O hydrogen bonding, which connects mol-ecules into chains parallel to the c axis.

Bis(2,4-dimethyl-pyridinium) tetra-bromido-mercurate(II).

The asymmetric unit of the title compound, (C7H10N)2[HgBr4], consists of one cation and one half-anion, bis-ected by a twofold rotation axis passing through the metal atom. The anion exhibits a distorted tetra-hedral arrangement about the Hg(II) atom. In the crystal, the cations and anions are linked by N-H⋯Br hydrogen-bonding inter-actions along [010]. Cation-cation π-π stacking and Br⋯Br inter-molecular inter-actions are absent.

Bis(2,4,6-trimethyl-pyridinium) tetra-bromidozincate.

In the title compound, (C(8)H(12)N)(2)[ZnBr(4)], the coordination geometry of the anion is approximately tetra-hedral. The Zn-Br bond lengths range from 2.3901 (19) to 2.449 (2) Šand the Br-Zn-Br angles range from 107.09 (8) to 112.48 (8)°. In the crystal, each [ZnBr(4)](2-) anion is connected to four cations through two N-H⋯Br and two C-H⋯Br hydrogen bonds, forming two-dimensional ⋯(cation)(2)⋯anion⋯(cation(2))⋯ sheets parallel to the bc plane. Within each sheet, the anions are arranged in stacks with no significant inter-anion Br⋯Br inter-actions [the shortest being > 4.3 Å], while the cations are in chains, with weak π-π stacking inter-actions [centroid-centroid distance = 3.991 Å] between cations inter-acting with the same anion.

3-(Ammonio-meth-yl)pyridinium dibromide.

In the title salt, C(6)H(10)N(2) (2+)·2Br(-), the non-H atoms of the 3-methyl-pyridinium unit of the cation are almost coplanar (r.m.s. deviation = 0.0052 Å). In the crystal, the dications and Br anions are linked by a combination of six hydrogen bonds, viz. one N(py)-H⋯Br, two C-H⋯Br and three H(2)N-H⋯Br, into supra-molecular layers, parallel to the bc plane, composed of alternating R(2) (4)(10) and R(2) (4)(8) loops. Weak π-π inter-actions between cationic rings with centroid-centroid distances of 3.891 (2) Šare also observed.

2,6-Dimethyl-pyridinium bromide.

The asymmetric unit of the title salt, C(7)H(10)N(+)·Br(-), comprises two 2,6-dimethyl-pyridinium cations and two bromide anions. One cation and one anion are situated in general positions, while the other cation and the other anion lie on a crystallographic mirror plane parallel to (010). Each pair of ions inter-act via N-H⋯Br and C-H⋯Br hydrogen bonding, generating motifs depending on the cation and anion involved. Thus, the cation and the anion on the mirror plane generate infinite chains along the c axis, while the other ionic pair leads to sheets parallel to the ac plane. In the overall crystal packing, both motifs alternate along the b axis, with a single layer of the chain motif sandwiched between two double layers of the sheet motif. The sheets and chains are further connected via aryl π-π inter-actions [centroid-centroid distances = 3.690 (2) and 3.714 (2) Å], giving a three-dimensional network.

Redetermination of 2,2'-bipyridine-1,1'-diium dibromide.

In the title mol-ecular salt, C(10)H(10)N(2) (2+)·2Br(-), the dihedral angle between the aromatic rings is 20.83 (14)° and the N-H groups have a transoid conformaton [N-C-C-N = 158.5 (3)°]. In the crystal, the cations are linked to the anions by two N-H⋯Br and five C-H⋯Br hydrogen bonds, generating corrugated sheets incorporating R(2) (1)(7), R(4) (2)(10), R(4) (2)(11) and two different R(4) (2)(12) loops. This structure was originally reported by Nakatsu et al. [Acta Cryst (1972), A28, S24], but no atomic coordinates are available.

Bis(2,6-dimethyl-pyridinium) dibromo-iodate bromide.

In the title salt, 2C(7)H(10)N(+)·IBr(2) (-)·Br(-), each of the anions, viz. [IBr(2)](-) and Br(-), lie on a twofold axis. The IBr(2) (-) anion is almost linear, with a Br-I-Br angle of 178.25 (3)°. The cation is essentially planar (r.m.s. deviation = 0.0067 Å). In the crystal, each Br(-) anion links two cations via N-H⋯Br⋯H-N hydrogen-bonding inter-actions.

2-Amino-5-methyl-pyridinium dibromo-iodate.

In the title salt, C(6)H(9)N(2) (+)·Br(2)I(-), the cation is essentially planar (r.m.s. deviation = 0.0062 Šfor the non-H atoms) while the anion is almost linear with a Br-I-Br angle of 177.67 (2)°. The crystal packing shows two anions and two cations connected via N-H⋯Br and (pyridine)N-H⋯Br hydrogen-bonding inter-actions, forming centrosymmetric tetra-mers with R(4) (4)(16) ring motifs. Very weak offset aromatic π-π stacking interactions [centroid-centroid separation = 4.038 (4), slippage = 1.773 Å] also occur.

3-Methyl-amino-3-phenyl-propan-1-ol.

The title compound, C(10)H(15)NO, is an amino alcohol with the hy-droxy group residing on the terminal C atom. Apart from the hy-droxy group and the phenyl ring, all non-H atoms are almost coplanar. In the crystal, classical O-H⋯N and N-H⋯O hydrogen bonds connect the mol-ecules into centrosymmetric dimers [R(2) (2)(12) descriptor] and tetra-meric units [R(4) (4)(8) descriptor] as ring motifs, consolidating a three-dimensional network.

Bis(N,N',N''-triisopropyl-guanidinium) fumarate-fumaric acid (1/1).

The asymmetric unit of the title compound, C(10)H(24)N(3) (+)·0.5C(4)H(2)O(4) (2-)·0.5C(4)H(4)O(4), comprises a triisopropyl-guanidinium cation, half of a fumarate dianion and half of a fumaric acid mol-ecule; both the fumarate dianion and the fumaric acid mol-ecule are located on inversion centres. In the crystal, inter-molecular O-H⋯O hydrogen bonds between the carboxyl groups of the fumaric acid mol-ecules and the carboxyl-ate groups of the fumarate anions lead to the formation of a hydrogen-bonded supra-molecular twisted chain along the b axis. The triisopropyl-guanidinium cations inter-act with the fumarate-fumaric acid chains via extensive N-H⋯O and C-H⋯O hydrogen bonds, leading to a ladder arrangement, with the cation being the rungs that bridge three curled chains of fumarate-fumaric acid. The crystal packing is stabilized by N-H⋯O and C-H⋯O (cation⋯fumarate/fumaric) and O-H⋯O (fumarate⋯fumaric) hydrogen bonds, consolidating a three-dimensional network.

N,N',N''-Tricyclo-hexyl-guanidinium iodide.

In the title compound, C(19)H(36)N(3) (+)·I(-), the orientation of the cyclo-hexyl rings around the planar (sum of N-C-N angles = 360°) CN(3) (+) unit produces steric hindrance around the N-H groups. As a consequence of this particular orientation of the tricyclo-hexyl-guanidinium cation (hereafter denoted CHGH(+)), hydrogen bonding is restricted to classical N-H⋯I and non-clasical (cyclo-hex-yl)C-H⋯I hydrogen bonds. The propeller CHGH(+) cation and the oriented hydrogen-bonding interactions lead to a three-dimensional supra-molecular structure.

Unexpected formation of a co-crystal containing the chalcone (E)-1-(5-chloro-thio-phen-2-yl)-3-(3-methyl-thio-phen-2-yl)prop-2-en-1-one and the keto-enol tautomer (Z)-1-(5-chloro-thio-phen-2-yl)-3-(3-methyl-thio-phen-2-yl)prop-1-en-1-ol.

The title crystal structure is assembled from the superposition of two mol-ecular structures, (E)-1-(5-chloro-thio-phen-2-yl)-3-(3-methyl-thio-phen-2-yl)prop-2-en-1-one, C12H9ClOS2 (93%), and (Z)-1-(5-chloro-thio-phen-2-yl)-3-(3-methyl-thio-phen-2-yl)prop-1-en-1-ol, C12H11ClOS2 (7%), 0.93C12H9ClOS2·0.07C12H11ClOS2. Both were obtained from the reaction of 3-methyl-thio-phene-2-carbaldehyde and 1-(5-chloro-thio-phen-2-yl)ethanone. In the extended structure of the major chalcone component, mol-ecules are linked by a combination of C-H⋯O/S, Cl⋯Cl, Cl⋯π and π-π inter-actions, leading to a compact three-dimensional supra-molecular assembly.

Synthesis, characterization, crystal structure and supra-molecularity of ethyl (E)-2-cyano-3-(3-methyl-thio-phen-2-yl)acrylate and a new polymorph of ethyl (E)-2-cyano-3-(thio-phen-2-yl)acrylate.

The synthesis, crystal structure and structural motif of two thio-phene-based cyano-acrylate derivatives, namely, ethyl (E)-2-cyano-3-(3-methyl-thio-phen-2-yl)acrylate (1), C11H11NO2S, and ethyl (E)-2-cyano-3-(thio-phen-2-yl)acrylate (2), C10H9NO2S, are reported. Derivative 1 crystallized with two independent molecules in the asymmetric unit, and derivative 2 represents a new monoclinic (C2/m) polymorph. The mol-ecular conformations of 1 and the two polymorphs of 2 are very similar, as all non-H atoms are planar except for the methyl of the ethyl groups. The inter-molecular inter-actions and crystal packing of 1 and 2 are described and compared with that of the reported monoclinic (C2/m) polymorph of derivative 2 [Castro Agudelo et al. (2017 ▸). Acta Cryst. E73, 1287-1289].