Роль семьи в процессе первичной социализации в отечественной и зарубежной литературе

A series of 5,15 push–pull <i>meso</i>-diarylzinc­(II) porphyrinates, carrying one or two −COOH or −COOCH₃ acceptor groups and a −OCH₃ or a −N­(CH₃)₂ donor group, show in <i>N</i>,<i>N</i>-dimethylformamide and CHCl₃ solutions a negative and solvent-dependent second-order nonlinear-optical (NLO) response measured by the electric-field-induced second-harmonic generation (EFISH) technique, different from the structurally related zinc­(II) porphyrinate carrying a −N­(CH₃)₂ donor group and a −NO₂ acceptor group, where a still solvent-dependent but positive EFISH second-order response was previously reported. Moreover, when a −N­(CH₃)₂ donor group and a −COOH acceptor group are part of a sterically hindered 2,12 push–pull β-pyrrolic-substituted tetraarylzinc­(II) porphyrinate, the EFISH response is positive and solvent-independent. In order to rationalize these rather intriguing series of observations, EFISH measurements have been integrated by electronic absorption and IR spectroscopic investigations and by density functional theory (DFT) and coupled-perturbed DFT theoretical and ¹H pulsed-gradient spin-echo NMR investigations, which prompt that the significant concentration effects and the strong influence of the solvent nature on the NLO response are originated by a complex whole of different aggregation processes induced by the −COOH group

Assessment of DFT Functionals for QTAIM Topological Analysis of Halogen Bonds with Benzene

Halogen bonding, a noncovalent interaction between a halogen atom and a nucleophilic site, is receiving a growing attention in the chemical community stimulating a large number of theoretical investigations. The density functional theory (DFT) approach revealed to be one of the most suitable methods owing to its accuracy and low computational cost. We report here a detailed analysis of the performance of an extensive set of DFT functionals in reproducing accurate binding energies and topological properties for the halogen-bonding interaction of either NCX or PhX molecules (X = F, Cl, Br, I) with the aromatic system of benzene in the T-shaped configuration. It was found that the better performance for both sets of properties is provided by a small subset of functionals able to take into account, implicitly or explicitly (by inclusion of an additive pairwise potential), the dispersion contribution, that is, ωB97X, M06-2X, M11, mPW2PLYP-D, and B2PLYP-D3

Direct Evidence of Torsional Motion in an Aggregation-Induced Emissive Chromophore

The aggregation induced emission (AIE) behavior shown by organic chromophores is very interesting for the development of efficient solid state devices. The restriction of intramolecular rotation is by far the most frequently assumed mechanism to explain this behavior; by blocking or reducing this rotation, upon rigidification of the environment, molecular luminescence is restored. By means of ultrafast pump–probe spectroscopy combined with density functional theory (DFT) and time-dependent DFT calculations, we show direct evidence of intramolecular rotation in a simple push–pull organic chromophore,4-diethylamino-2 benzylidene malonic acid dimethyl ester, possessing AIE properties. The spectral evolution of the stimulated emission band of the chromophore in the first 45 ps after photoexcitation is fully consistent with the presence of a torsional relaxation toward the equilibrium geometry of the excited state, taking place on time scales that depend on the solvent viscosity. The structural features of the excited state fully account for the different photoluminescence efficiencies observed in solvents with different viscosities

Light-Induced Regiospecific Bromination of <i>meso</i>-Tetra(3,5-di-<i>tert</i>-butylphenyl)Porphyrin on 2,12 β‑Pyrrolic Positions

The antipodal introduction of two bromine atoms on the 2,12 β-pyrrolic position of 5,10,15,20-tetra­(3,5-di-<i>tert</i>-butylphenyl)­porphyrin was successfully achieved by a light-induced reaction of the substrate with excess NBS. Complexation with Ni^II of the major regioisomer led to good quality crystals, suitable for X-ray structure determination with unprecedented probability levels. The regiospecific character of the synthetic procedure and the exactness of the bromine atom position assignment were thus confirmed, suggesting an unexpected electrophilic aromatic substitution pathway rather than a free-radical halogenation process. A QTAIM topological analysis on the DFT-optimized wave function of the monosubstituted free-base porphyrin intermediate carrying a bromine atom in C2 β-pyrrolic position confirmed the largest negative charge for the C12 carbon atom in antipodal position, in agreement with the proposed electrophilic aromatic substitution mechanism

Mapping of the molecular electrostatic potential onto <i>p</i>-aminobenzoate anion (<i>p</i>ABA⁻) and <i>p</i>ABA accessible surface area.

<p>Mapping of the molecular electrostatic potential onto <i>p</i>-aminobenzoate anion (<i>p</i>ABA⁻) and <i>p</i>ABA accessible surface area.</p

Hydrogen-bonding geometry (Å) for compound HEA-<i>p</i>ABA.

<p>Hydrogen-bonding geometry (Å) for compound HEA-<i>p</i>ABA.</p

Bond lengths (Å) and angles (°) for HEA-<i>p</i>ABA.

<p>Bond lengths (Å) and angles (°) for HEA-<i>p</i>ABA.</p

Crystal packing of HEA-<i>p</i>ABA.

<p>A. Crystal packing of HEA-<i>p</i>ABA representing the <i>2-D</i> layers parallel to (<i>100</i>) plane. B. Fragment of molecular packing in the crystal of HEA-<i>p</i>ABA.</p

ORTEP drawing for HEA-<i>p</i>ABA.

<p>The atomic labeling and charge-assisted hydrogen bonds are represented by dashed lines. Thermal ellipsoids are shown with the 50% probability level.</p

Crystal Data and Structure Refinement for HEA-<i>p</i>ABA.

<p>Crystal Data and Structure Refinement for HEA-<i>p</i>ABA.</p