The title compound, C(23)H(17)N(3)O(3), has an E configuration with respect to the C=N bond. The dihedral angle between the two phenyl rings bonded to the hydrazine group is 86.45 (13)°. The furan ring makes dihedral angles of 3.4 (2) and 7.06 (13)°, respectively, with the methyl-idenehydrazine C=N-N plane and the benzene ring.

In the crystal structure of the title compound, C(9)H(13)N(3)S, mol-ecules are linked through N-H⋯S and N-H⋯N hydrogen bonds, forming hydrogen-bonded tapes along the b axis. The dihedral angle between the phenyl ring and the thiourea group is 44.9 (2)°.

PURPOSE There is insufficient data regarding the durability of porcelain laminate veneers bonded to existing composite fillings. The aim of the present study was to evaluate the fracture resistance and microleakage of porcelain laminate veneers bonded to teeth with existing composite fillings. MATERIALS AND METHODS Thirty maxillary central incisors were divided into three groups (for each gro...

The structures of 2-acetamido-4-tolyl-1,3-thiazole, C(12)H(12)N(2)OS, (I), and 2-amino-4-tolyl-1,3-thiazolium chloride dihydrate, C(10)H(11)N(2)S(+).Cl(-).2H(2)O, (II), reveal that both molecules are essentially planar, with the respective dihedral angles between the benzene and thiazole rings being 2.9 (1) and 10.39 (7) degrees . Compound (I) associates via a single N-H...O interaction to form...

In the title compound, C(19)H(17)N(3)O(2), the dihedral angles between the pyrimidine ring and the two benzene rings are 34.87 (12) (for the directly-bonded ring) and 69.57 (12)°. An intra-molecular N-H⋯O hydrogen bond occurs. The crystal packing features inter-molecular N-H⋯O hydrogen bonds.

In the structure of the title compound, C(37)H(40)N(4)O(8), penta-erythrityltetra-mine is bonded to four o-vanillin mol-ecules, forming a four-armed Schiff base mol-ecule. These mol-ecules are connected by inter-molecular C-H⋯O hydrogen bonds. Intramolecular C-H⋯N and O-H⋯N hydrogen bonds are also present.

Cyclic eight-membered hydrogen-bonded rings exist in the title compound, C(5)H(7)N(2)(+).C(7)H(5)O(2)(-), involving the 2-aminopyridinium and benzoate ions. Each benzoate ion has two intramolecular hydrogen bonds. 2-Aminopyridinium benzoate ion pairs are linked by N-H...O hydrogen bonds, with an N...O distance of 2.8619 (14) A.

In the title compound, C(11)H(9)ClN, the dihedral angle between the aromatic ring planes is 44.2 (1)° and the bridging C-N-C bond angle is 127.60 (19)°. The amino N-H grouping makes a hydrogen bond to the pyridyl N atom of an adjacent mol-ecule across a center of inversion, generating a hydrogen-bonded dimer.

In the crystal structure of the title compound, (C(12)H(12)N(4)O(2))(2)[Mo(8)O(26)], the amino and pyridinium groups of the N(1),N(2)-di(pyridinium-4-yl)oxalamide cations are hydrogen bonded to the O atoms of the centrosymmetric isopolyoxometalate β-[Mo(8)O(26)](4-) anions, forming a three-dimensional supra-molecular architecture.

The title compound, C(7)H(10)N(2)O, crystallizes with two independent mol-ecules in the asymmetric unit. The bond lengths and angles in the mol-ecules are within normal ranges. The crystal structure is stabilized by inter-molecular N-H⋯N hydrogen bonds, linking the two independent mol-ecules into hydrogen-bonded dimers.