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

Probing the Association of Frustrated Phosphine–Borane Lewis Pairs in Solution by NMR Spectroscopy

¹⁹F,¹H HOESY, diffusion, and temperature-dependent ¹⁹F and ¹H NMR studies allowed us to unequivocally probe the association between the frustrated PR₃/B­(C₆F₅)₃ (<b>1</b>, R = CMe₃; <b>2</b>, R = 2,4,6-Me₃C₆H₂) Lewis pairs in aromatic solvents. No preferential orientation is favored, as deduced by combining ¹⁹F,¹H HOESY and DFT results, suggesting association via weak dispersion rather than residual acid/base interactions. The association process is slightly endoergonic [<i>K</i> = 0.5 M^–1, Δ<i>G</i>⁰(298 K) = +0.4 kcal/mol for <b>2</b>], as derived from diffusion NMR measurements

Unlocking Structural Diversity in Gold(III) Hydrides: Unexpected Interplay of <i>cis</i>/<i>trans</i>-Influence on Stability, Insertion Chemistry, and NMR Chemical Shifts

The synthesis of new families of stable or at least spectroscopically observable gold­(III) hydride complexes is reported, including anionic <i>cis</i>-hydrido chloride, hydrido aryl, and <i>cis</i>-dihydride complexes. Reactions between (C^C)­AuCl­(PR₃) and LiHBEt₃ afford the first examples of gold­(III) phosphino hydrides (C^C)­AuH­(PR₃) (R = Me, Ph, <i>p</i>-tolyl; C^C = 4,4′-di-<i>tert</i>-butylbiphenyl-2,2′-diyl). The X-ray structure of (C^C)­AuH­(PMe₃) was determined. LiHBEt₃ reacts with (C^C)­AuCl­(py) to give [(C^C)­Au­(H)­Cl]⁻, whereas (C^C)­AuH­(PR₃) undergoes phosphine displacement, generating the dihydride [(C^C)­AuH₂]⁻. Monohydrido complexes hydroaurate dimethylacetylene dicarboxylate to give <i>Z</i>-vinyls. (C^N^C)Au pincer complexes give the first examples of gold­(III) bridging hydrides. Stability, reactivity and bonding characteristics of Au­(III)–H complexes crucially depend on the interplay between <i>cis</i> and <i>trans</i>-influence. Remarkably, these new gold­(III) hydrides extend the range of observed NMR hydride shifts from δ −8.5 to +7 ppm. Relativistic DFT calculations show that the origin of this wide chemical shift variability as a function of the ligands depends on the different ordering and energy gap between “shielding” Au­(d_π)-based orbitals and “deshielding” σ­(Au–H)-type MOs, which are mixed to some extent upon inclusion of spin–orbit (SO) coupling. The resulting ¹H hydride shifts correlate linearly with the DFT optimized Au–H distances and Au–H bond covalency. The effect of <i>cis</i> ligands follows a nearly inverse ordering to that of <i>trans</i> ligands. This study appears to be the first systematic delineation of <i>cis</i> ligand influence on M–H NMR shifts and provides the experimental evidence for the dramatic change of the ¹H hydride shifts, including the sign change, upon mutual <i>cis</i> and <i>trans</i> ligand alternation

Organometallic Iridium Catalysts Based on Pyridinecarboxylate Ligands for the Oxidative Splitting of Water

Organometallic compounds [Cp*Ir­(κ²-N,O)­X] (κ²-N,O = 2-pyridinecarboxylic acid, ion(−1) (<b>1</b>), 2,4-pyridinedicarboxylic acid, ion(−1) (<b>2</b>), 2,6-pyridinedicarboxylic acid, ion(−1) (<b>3</b>); X^– = Cl^– (<b>a</b>), NO₃^– (<b>b</b>)) and [Ir­(κ³-N,O,O)­(1-κ-4,5-η²-C₈H₁₃)­(MeOH)] (κ³-N,O,O = 2,6-pyridinedicarboxylic acid, ion(−2) (<b>4</b>)) are effective catalysts for the oxidative splitting of water to O₂ driven by Ce⁴⁺. They show similar TOF_LT values (long-term TOF, 2.6–7.4 min^–1) while TOF_IN values (initial TOF) strongly depend on the catalyst (<b>1</b> ≫ <b>2</b> > <b>3</b> > <b>4</b>), reaching a maximum value of 287 min^–1 (4.8 s^–1) for <b>1a</b>, which is the highest TOF value ever reported for an iridium catalyst. Voltammetric measurements indicate that the oxidative processes of compounds <b>1</b>–<b>4</b> are located at values substantially less positive than that of [Cp*Ir­(bzpy)­NO₃] (bzpy = 2-benzoylpyridine; Δ<i>E</i> ≈ 0.2–0.3 V), taken as reference catalyst for water oxidation. In particular, compound <b>3</b>, having a pendant −COOH moiety in close proximity to an iridium coordination site, as shown by the structure determined by single-crystal X-ray diffraction, exhibits several low-potential oxidation processes

Solventless Supramolecular Chemistry via Vapor Diffusion of Volatile Small Molecules upon a New Trinuclear Silver(I)-Nitrated Pyrazolate Macrometallocyclic Solid: An Experimental/Theoretical Investigation of the Dipole/Quadrupole Chemisorption Phenomena

A comparative study on the tendency of a new trinuclear silver­(I) pyrazolate, namely, [<i>N</i>,<i>N</i>-(3,5-dinitropyrazolate)­Ag]₃ (<b>1</b>), and a similar compound known previously, [<i>N</i>,<i>N</i>-[3,5-bis­(trifluoromethyl)­pyrazolate]­Ag]₃ (<b>2</b>), to adsorb small volatile molecules was performed. It was found that <b>1</b> has a remarkable tendency to form adducts, at room temperature and atmospheric pressure, with acetone, acetylacetone, ammonia, pyridine, acetonitrile, triethylamine, dimethyl sulfide, and tetrahydrothiophene, while carbon monoxide, tetrahydrofuran, alcohols, and diethyl ether were not adsorbed. On the contrary, <b>2</b> did not undergo adsorption of any of the aforementioned volatile molecules. Adducts of <b>1</b> were characterized by elemental analysis, IR, thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET) surface area, and diffusion NMR measurements. The crystal structures of <b>1</b>·2CH₃CN and compound <b>3</b>, derived from an attempt to crystallize the adduct of <b>1</b> with ammonia, were determined by single-crystal X-ray diffractometric studies. The former shows a sandwich structure with a 1:2 stoichiometric [Ag₃]/[CH₃CN] ratio in which one acetonitrile molecule points above and the other below the centroid of the Ag₃N₆ metallocycle. Compound <b>3</b> formed via rearrangement of the ammonia adduct to yield an anionic trinuclear silver­(I) derivative with an additional bridging 3,5-dinitropyrazolate and having [Ag­(NH₃)₂]⁺ as the counterion, [Ag­(NH₃)₂]­[<i>N</i>,<i>N</i>-(3,5-dinitropyrazolate)₄Ag₃]. Irreversible sorption and/or decomposition upon vapor exposure are desirable advantages toward toxic gas filtration applications, including ammonia inhalation. TGA confirms the analytical data for all of the samples, showing weight loss for each adsorbed molecule at temperatures significantly higher than the corresponding boiling temperature, which suggests a chemical-bonding nature for adsorption as opposed to physisorption. BET surface measurements of the “naked” compound <b>1</b> excluded physical adsorption in its porous cavities. Density functional theory simulation results are also consistent with the chemisorption model, explain the experimental adsorption selectivity for <b>1</b>, and attribute the lack of similar adsorption by <b>2</b> to significantly less polarizable electrostatic potential and also to strong argentophilic bonding whose energy is even higher than the quadrupole–dipole adduct bond energy upon proper selection of the density functional