IN THE TITLE COMPOUND [SYSTEMATIC NAME: bis-(4-meth-oxy-3,4-di-hydro-quinazolin-1-ium) 2,5-di-chloro-3,6-dioxo-cyclo-hexa-1,4-diene-1,4-diolate], 2C9H11N2O(+)·C6Cl2O4 (2-), the chloranil-ate anion lies about an inversion center. The 4-meth-oxy-3,4-di-hydro-quinazolin-1-ium cations are linked on both sides of the anion via bifurcated N-H⋯(O,O) and weak C-H⋯O hydrogen bonds, giving a centrosymmet...

The conformational stability of hexahydropyridobenzodioxin and related derivatives in both protonated and non-protonated forms have been investigated by means of ab initio molecular orbital methods as well as semi-empirical AM1 and PM3 methods. One of the cis conformers (cis2e) has been found to be most stable due to the formation of an intramolecular hydrogen bond, other conformers including t...

The vicinity of a hydrogen bond donor (O–H) and a hydrogen bond acceptor (C=O or C=N– R) in salicylaldehydes and ortho-Schiff bases results in significant structural variations compared to the monosubstituted derivatives that are reflected in the electronic structure and thus in the spectroscopic properties. This interplay between intramolecular hydrogen bonding and multicenter πelectron deloca...

In the title compound, C(16)H(15)ClN(2)O(3)·H(2)O, the water mol-ecule is linked to the Schiff base mol-ecule via an O-H⋯O hydrogen bond. In the Schiff base mol-ecule, an intramolecular O-H⋯N hydrogen bond occurs and the dihedral angle between the two benzene rings is 20.5 (5)°. In the crystal, the Schiff base and water mol-ecules are linked by inter-molecular N-H⋯O and O-H⋯O hydrogen bonds, fo...

The mol-ecule of accanthomine A, C(15)H(13)N(5), is approximately planar, with the indolyl fused-ring and the pyrimidyl ring being twisted by 31.7 (1)° The amino group of the five-membered ring is an intramolecular hydrogen-bond donor to a nitro-gen acceptor of the pyrimide ring. The amino group of the pyrimide ring is a hydrogen-bond donor to the N atoms of adjacent mol-ecules. These hydrogen-...

We discuss theoretically the geometric and electronic structure properties of the thiazolidinedione derivative A and its hydrogen-bonded complex in dimethylformamide (DMF) solution in the S0 and S1 states. To gain insight into the photoinduced coupled excited-state proton transfer (ESPT) and twisted intramolecular charge transfer (TICT) associated with intermolecular hydrogen bonding, the poten...

We have synthesized a molecule containing a tight hydrogen-bonding interaction between an alcohol and a nonconjugated π-system. The strength of this hydrogen bond results in a large red shift, nearly 189 cm(-1), on the alcohol stretching frequency in the IR spectrum in comparison to a free alcohol control. The interaction is notable in that it possesses a better defined intramolecular hydrogen ...

Ab initio and density functional calculations are applied to study the influence of an increasing number of chlorine substituents on the properties of the intramolecular hydrogen bond in substituted Mannich bases. It is shown, that not only the acidity of the proton donor, which depends on the number of chlorine atoms at the aromatic ring, but also steric interactions modify the geometry of the...

In molecules of the title compound, C(14)H(12)N(2)O(4), the conformation is dominated by an intramolecular N-H.O hydrogen bond in which one of the nitro O atoms is the acceptor. The molecules are linked by paired C-H.O hydrogen bonds [H.O = 2.41 A, C.O = 3.2990 (17) A and C-H.O = 156 degrees ] into centrosymmetric R(2)(2)(14) dimers; these dimers are linked weakly into chains of alternating R(2...

In the title compound, C(11)H(16)ClNO, the side chain of the ethyl-amine group is almost perpendicular to the benzene ring; the dihedral angle between the C/C/N plane of the ethyl-amine grouping and the benzene plane is 87.4 (2)°. An intramolecular N-H⋯O hydrogen bond occurs. In the crystal structure, mol-ecules are connected weakly by O-H⋯N hydrogen bonds, forming a tetra-mer around the symmet...