In the title complex, [CuCl(2)(C(17)H(11)N(3)O(2))(2)], the Cu(II) ion is located on an inversion center. It exhibits a distorted octa-hedral coordination geometry defined by two chloride anions at trans sites and four 3-pyridyl N atoms at equatorial sites from two (6-nicotinoyl-2-pyrid-yl)(3-pyrid-yl)methanone ligands. The (6-nicotinoyl-2-pyrid-yl)(3-pyrid-yl)methanone ligand can be viewed as ...

The complete mol-ecule of the title compound, C(20)H(20)N(2)O(4)S(2), is generated by crystallographic twofold symmetry, with two C atoms lying on the rotation axis. The dihedral angle between the central benzene ring and the pendant ring is 68.42 (6)° and the dihedral angle between the pendant rings is 45.11 (5)°. The torsion angles for the C-S-N-C and S-N-C-C fragments are -73.22 (15) and -15...

A survey of our recent work on synthetic polynucleotide analogs is given. Propionic acid and 3-methyl butyric acid derivatives substituted in the 2-position with nucleic acid bases have been used as chiral pendants for attachment to hydrophilic polyamine backbones. Hindered rotation about the amide bonds formed promotes a base-stacked structure as shown by ultraviolet hypochromic effects versus...

Recently, discrete and variable Adriatic indices have been introduced and it has been shown that the sum α -exdeg index is good predictor (when variable parameter is equal to 0.37 ) of the octanol-water partition coefficient for octane isomers. Here, we study mathematical properties of this descriptor. Namely, we analyze extremal graphs of this descriptor in the following classes: the class of ...

In the title compound, C(21)H(19)N(3)O(4), two intramolecular N-H⋯O hydrogen bonds generate two six-membered rings. The dihedral angles between the central heterocyclic ring and the two pendant rings are 61.5 (2) and 63.5 (1)°.

The title compound, 2C(21)H(19)N(3)O(2)·H(2)O, was synthesized by a Schiff base condensation of 2,6-diformyl-pyridine with 2-amino-4-methyl-phenol in ethanol. In the crystal, two mol-ecules of 2,6-bis-[(2-hy-droxy-5-methyl-phen-yl)imino-meth-yl]pyridine dimer-ize via hydrogen bonding to a water mol-ecule, which lies on a twofold axis. There are also intra-molecular phenol-imine hydrogen bonds. ...

The distinguishing number ∆(X) of a graph X is the least positive integer n for which there exists a function f : V (X) → {0, 1, 2, · · · , n−1} such that no nonidentity element of Aut(X) fixes (setwise) every inverse image f−1(k), k ∈ {0, 1, 2, · · · , n − 1}. All infinite, locally finite trees without pendant vertices are shown to be 2distinguishable. A proof is indicated that extends 2-disti...

Several polysiloxanes (polydimethyl, polymethyloctadecyl or polymethyltetradecyl-siloxane) were studied by FTIR spectroscopy, densimetry and gel permeation chromatography. Different types of ageings such as thermal ageing (60°C and 100°C), photo-ageing (SEPAP) and acid vapour ageing were performed and compared. Oxidation, chain scission and cross-linking were estimated after ageings. The presen...

Eight metal complexes of the type [M(tpy)2](2+) (tpy = 2,2':6',2''-terpyridine) featuring four pendant pyridine rings are reported and characterised by NMR, MS, absorption spectroscopy and electrochemical methods. Palladium-mediated Suzuki and Sonogashira cross-coupling reactions were performed on both free 4'-(3,5-dibromophenyl)-tpy and its Ru(II) complex in good yields. The ready N-alkylation...

Du, Zhou and Trinajstić [J. Math. Chem., 48, pp. 697–703, 2010] proved that in the set of n-vertex connected unicyclic graphs G with n ≥ 3, for –1 ≤ α < 0, the graph consisting of a triangle and n – 3 pendant vertices adjacent to the same vertex of this triangle is the unique graph with the minimum general sum-connectivity index. In this paper, using a graph transformation and several inequalit...