Vol 60, No 1 (2019)

Schrödinger equations for helium-like ions from H⁻ to Ar¹⁶⁺ are solved by a novel method using the surfaces of the constant potential of electron-electron interaction. Similar to the method of configuration interaction, the wave function is represented as a linear combination of configuration wave functions, with the difference that their coefficients (referred to below as “configuration weight functions”), depend on the interaction potential. The basis functions are represented by the wave functions of noninteracting electrons in the Coulomb field of atomic nuclei. In the single-configuration approximation, the energies calculated for the ions appear to be lower than those calculated within the Hartree-Fock limit. The accuracy of energy calculations using three configurations (1s, 2s, and 3s functions) is close to the accuracy achieved with 35 configurations within the method of configuration interaction. The account of four configurations provides lower energies than those obtained by the configuration interaction method and slightly lower than those obtained with Hylleraas wave functions.

Targeted drug delivery systems are very suitable for medical usages. This investigation studies the interaction of anti-cancer drug gemcitabine with C₆₀ and C₇₀ fullerenes by the DFT method at a B3LYP/cc-pvdz quantum chemical level. In addition, the investigation is carried out on the drug delivery capability of gemcitabine. To achieve suitable and optimized adsorption of the drug on the surface of fullerenes (C₆₀ and C₇₀), an carbon atom is replaced by an aluminum atom in fullerene structures. Then, the geometric parameters, HOMO and LUMO energies, and the energy gap are reported and compared, and also the density of state (DOS) plots for Al-doped fullerenes and their complexes with the drug are traced. The obtained results show that the orbital energy levels decrease significantly by the gemcitabine bonding to C₆₀and C₇₀ fullerenes. Other specifications such as chemical potential, chemical hardness, and electrophilicity also vary significantly in these structures. The interpretation of these variations may depend on the electron affinity of C₆₀ and C₇₀ fullerenes.

(E)-2-((4-tert-butylbenzylimino)methyl)-4-methoxyphenol is synthesized by the reaction of 4-tert-buthylbenzylamine with 5-methoxysalicylaldehyde. The structure of the Schiff base is investigated by FT-IR, UV-visible, and ¹H NMR, ¹³C NMR, and X-ray data. Moreover, the molecular structure, molecular electrostatic potential surfaces (MEP), frontier molecular orbitals, and nonlinear optical properties (NLO) are also investigated by density functional theory (DFT) calculations. The experimental and calculated results show that the phenol-imine form of the compound is more favoured than the keto-amine form. The most energy favourable docked structures are obtained from the rigid molecular docking of the compound with DNA. The compound binds at the active site of DNA proteins by weak non-covalent interactions. UV-Vis spectroscopy studies of the interactions between the compounds and calf thymus DNA (CT-DNA) show that the compounds interact with CT-DNA via the electrostatic and intercalative binding. The compound inhibits the frameshift and base pair mutations in the absence of S9 mix with a high inhibition rate. Also, the molecular docking is made to identify the interaction between the ligand and DNA.

Binuclear complex [Cu₂L(μ₂-pz)] (pz = pyrazolate anion) of copper(II) with the condensation product of 1,3-diamino-2-propanol (DAP) and 4-formyl-3-formylcoumarin (H₃L) is synthesized and characterized. Magnetic properties of the complex are compared with those demonstrated by a number of previously studied compounds based on bis-azomethine derivatives of DAP with the structure similar to that of studied compounds, i.e. identical exchange fragments and immediate donor environments of copper(II) ions. Antiferromagnetic exchange parameters of these complexes are calculated within the DFT method using the “broken-symmetry” approximation. It is shown for the complexes with the same structure of the exchange fragment and the nearest donor environment of metal centers that the significant variation of the exchange parameter (∼100 cm⁻¹) is determined by the electronic nature of non-bridging donor oxygen atoms of the carbonyl fragment of the bis-azomethine ligand.

Formation of molecular cycles on the surface of crystalline silver iodide in contact with water vapor is simulated by the Monte Carlo method. The pictures of molecular chains and rings formed on the crystalline substrate are obtained. The stability of molecular associates under thermal fluctuations is analyzed in terms of free energy and entropy calculated from the first principles of statistical mechanics. An improved model is used to describe the molecular forces of adhesion to the crystalline substrate by taking into account long-range polarization and dispersion interactions. The field of the crystalline substrate facilitates formation of five- and six-molecule rings and prevents formation of four-molecule rings. The displacement of five-molecule rings by six-molecule rings is a collective effect requiring that a sufficient number of molecules be accumulated on the surface.

Crystal hydrate of sodium salt of an oxovanadium(IV) complex with nitrilo-tris-methylenephosphonic (NTP) acid Na₈[(VO)₂(μ−O)₂{(VO)μ³−N(CH₂PO₃)₃}₂]·20H₂O is synthesized, isolated, and studied: space group P1̅, Z = 2, a = 12.5829(2) Å, b = 13.9297(2) Å, c = 15.1051(3) Å, α = 72.233(2)°, β = 76.907(2)°, γ = 70.388(2)°. The NTP ions are completely deprotonated and hexadentate. In coordinating the VO²⁺ ion each NTP ion closes three N–V–O–P–C cycles with a common N–V bond. By means of bridging vanadyl ions and oxo ligands the four-membered V–O–V–O cycle and the [–V–O–P–O–]₄ macrocycle are closed. Coordination V polyhedra are distorted tetragonal pyramids. With regard to the occurrence of weak V–N bonds the polyhedra of two V atoms can be completed to strongly distorted octahedra.

Two isostructural compounds of the composition [M(NH₃)₆]₄[{M(NH₃)₂}{Re₃Mo₃Se₈(CN)₆}₂]·15H₂O (M = Co, Ni) are obtained by a reaction of a salt of heterometal cluster [Re₃Mo₃Se₈(CN)₆]⁵⁻ anion with cobalt or nickel salts in an aqueous ammonia solution. The obtained compounds are structurally characterized. They correspond to the class of cyano-bridged coordination polymers. Two cyano groups of the octahedral cluster in the trans position form bridging bonds with Co(II) and Ni(II) cations. The obtained compounds are composed of highly charged polymeric [{M(NH₃)₂}{Re₃Mo₃Se₈(CN)₆}2]_∞∞⁸⁻ 88 layers formed by cluster anions and metal cations. The negative charge of the layers is compensated by [M(NH₃)₆]²⁺ cationic complexes inside the polymeric layer and in the interstitial space of the structure.

The [Ni(Bipy)₃](Htba)₂·6H₂O (I) complex (Bipy is 2,2′-bipyridyl, H₂tba is 2-thiobarbituric acid) is synthesized and its structure is determined by single crystal XRD (cif-file CCDC No. 1836529). The crystals of I are monoclinic: a = 13.6618(6) Å, b = 23.9441(9) Å, c = 25.4335(8) Å, β = 93.091(1)°, V = 8307.7(5), space group P2₁/c, Z = 8. Via multiple intermolecular N–H⋯O, O–H⋯O, and C–H⋯S hydrogen bonds (HBs), the Htba⁻ ions and water molecules form channels within which [Ni(Bipy)₃]²⁺ cations are located. The Bipy molecules and the Htba⁻ ions are involved in C–H⋯O HBs and the π−π interaction. The results of the thermal analysis and IR spectroscopy agree with the single crystal XRD data.

A novel neodymium(III) chloride complex with 2,4′-bipyridine (bpy), (bpyH)[Nd(H₂O)₉]Cl₄·bpy·H₂O is synthesized, crystallized, and characterized by single crystal X-ray diffraction and thermal analysis. The crystal is nine-coordinate homoleptic mononuclear aqua complex and crystallizes in the triclinic P-1 space group with two formula units in the unit cell related by a pseudo-translation of b/2. In the crystal structure, each [Nd(H₂O)₉]³⁺ ion is hydrogen bonded in the same way to one 2,4′-bipyridine molecule, one 2,4-bipyridinium cation, and chloride anions. Lattice water molecules form hydrogen bonds which further stabilize the framework. The thermal properties of the compound in the solid state are studied using TG-DTG techniques under the dynamic flowing air atmosphere.

2-(Benzamido)thiazolylbenzoate is synthesized via a novel method. It is characterized by spectroscopy, micranalysis, and GC-MS. It crystallizes in the monoclinic space group P21/n with a = 19.8990(5), b = 7.3680(2), c = 22.3845(6) Å, β = 113.799(1)°, V = 3002.85(14) ųZ = 8. The HOMO-LUMO of the reactants and products are considered.

Two novel copper(II) complexes, Cu₂L₂(bipy) and Cu₂L₂(H₂O)₄·3H₂O of Schiff base ligands derived from the condensation of L-tert-leucine and L-isoleucine with 2,4-dihydroxybenzaldehyde, are synthesized and characterized by single crystal X-ray diffraction. Compounds crystallize in the orthorhombic crystal system. The Cu₂L₂(bipy) complex has a distorted square planar geometry with an N₂O₂ coordination environment. Water is contained in supramolecular network pores. On the other hand, in the Cu₂L₂(H₂O)₄·3H₂O complex, both copper atoms adopt a five-coordinated distorted square-pyramidal geometry with an NO₄ coordination environment and guest water molecules form a 1D water chain. Both complexes build a 2D supramolecular network.

In the original publication the affiliation was not correct. The correct affiliation is: Department of Chemistry, Central Tehran Branch, Islamic Azad University, Tehran, Iran.

In the original publication there was a typo in the title of the article. The correct title of the article is SYNTHESIS, CHARACTERIZATION, AND COMPUTATIONAL STUDIES OF TRIAZATETRACYCLO ACETAMIDE.