The partitioning of space with Hirshfeld surfaces enables the analysis fingerprint molecular interactions in crystalline environments. This study uses decomposition crystal contact surface between pairs interacting chemical species to derive an enrichment ratio. quantity propensity form intermolecular themselves and other species. ratio is obtained by comparing actual contacts those computed as if all types had same probability form. enrichments tendencies were analyzed several families...

Molecular geometries of benzene and its 18 monosubstituted derivatives were optimized at B3LYP/6-311+G** level theory. The changes pi-electron delocalization the fragment estimated by use aromatic stabilization energies (ASE) based on different homodesmotic reaction schemes, geometry-based HOMA model, magnetism-based NICS, NICS(1), NICS(1)zz, an electronic index, PDI, derived from AIM Apart other descriptors aromaticity vary to a very small extent, indicating high resistance structure...

Abstract Numerous studies on nitro group properties are associated with its high electron-withdrawing ability, by means of both resonance and inductive effect. The substituent effect the may be well described using either traditional constants or characteristics based quantum chemistry, i.e., cSAR, SESE, pEDA/sEDA models. Interestingly, cSAR descriptor allows to describe electron-attracting regardless position type system. Analysis classical reverse effects in various systems indicates...

The synthesis, complete characterization, and solid state structural solution conformation determination of calix[n]arenes (n = 4, 6, 8) is reported. A series X-ray structures the alkali metal salts calix[4]arene (HC4) illustrate great influence ion on structure calixanions (e.g., Li salt monoanionic HC4 a monomer; Na forms dimer; K, Rb, Cs exist in polymeric forms). Solution NMR spectra calix[4]arenes indicate that they have cone solution. Variable-temperature HC4.M (M Li, Na, Cs) show...

An application of a charge the substituent active region concept to 1-Y,4-X-disubstituted derivatives bicyclo[2.2.2]octane (BCO) [where Y = NO2, COOH, OH, and NH2 X NMe2, NH2, OMe, Me, H, F, Cl, CF3, CN, CHO, COMe, CONH2, NO] provides quantitative information on inductive component effect (SE). It is shown that highly additive but dependent kind substituents. SE stabilization energy characteristics 1,4-disubstituted BCO benzene allows definition resonance contributions overall SE. Good...

Structural parameters of a range over 100 meso-substituted zinc porphyrins were reviewed and compared to show how far the nature functional group may affect interatomic distances bond angles within porphyrin core. It was proved that even despite evident deformations molecular structure, involving twisting porphyrin's central plane, coupled π-bonding system remains flexible stable. DFT calculations applied number selected representative for compounds emphasize relevance theoretical methods in...

Structures of selected 3,6‐dihalogeno‐ N ‐alkyl carbazole derivatives were calculated at the B3LYP/6‐311++G(3df,2pd) level theory, and their 13 C nuclear magnetic resonance (NMR) isotropic shieldings predicted using density functional theory (DFT). The model compounds contained 9H, ‐methyl ‐ethyl derivatives. relativistic effect Br I atoms on was modeled spin–orbit zeroth‐order regular approximation (ZORA) method. Significant heavy atom shielding effects for carbon directly bonded with...

The role of theory level in prediction benzene magnetic indexes aromaticity is analysed and compared with calculated nuclear shieldings 3 He used as NMR probe. Three closely related nucleus-independent chemical shift (NICS) based were for at SCF-HF, MP2, DFT levels the impact basis set on these quantities was studied. changes NICS(0), NICS(1), NICS(1)zz parameters using MP2 several density functionals within 1 to ppm. Similar deviations between observed values selected sets. Only very small...

Electron-accepting properties of the nitro group were studied in a series meta- and para-X-substituted nitrobenzene derivatives (X = NMe2, NH2, OH, OMe, CH3, H, F, Cl, CF3, CN, CHO, COMe, CONH2, COOH, COCl, NO2, NO). For this purpose Hammett-like approaches applied based on quantum chemistry modeling; B3LYP/6-311++G(d,p) method was used. The substituent effect (SE) characterized by mutually interrelated descriptors: charge active region, cSAR(X), stabilization energy, SESE, as well...

Due to antimicrobial potential of S-containing compounds, the current study explores experimentally crystal and molecular structure three new thiosulfonates at 100 K, notably S-ethyl 4-aminobenzene-1-sulfonothioate (1), 4-acetamidobenzene-1-sulfonothioate (2), S-methyl (3). Theoretical analysis between their vibrational IR, Raman, as well NMR parameters is given. The details -SO2-S- structural motif are analyzed theoretically using HO-OH, HS-SH H3CS-SCH3, model molecules. experimental...

Wind and solar energy are two popular forms of renewable used in microgrids facilitating the transition towards net-zero carbon emissions by 2050. However, they exceedingly unpredictable since rely highly on weather atmospheric conditions. In microgrids, smart management systems, such as integrated demand response programs, permanently established a step-ahead basis, which means that accurate forecasting wind speed irradiance intervals is becoming increasingly crucial to optimal operation...

A combined experimental and theoretical study has been performed on 9-benzyl-3,6-diiodo-9H-carbazole. Experimental X-ray (100.0 K) room-temperature 13C nuclear magnetic resonance (NMR) studies were supported by advanced density functional theory calculations. The non-relativistic structure optimization was the shieldings predicted at relativistic level of using zeroth-order regular approximation. changes in benzene pyrrole rings compared to unsubstituted carbazole or parent molecules...

Abstract Molecular geometries of phenol and its 17 p ‐substituted derivatives were optimized at the B3LYP/6–311 + G** level theory. Three homodesmotic three isodesmotic reaction schemes used to estimate aromatic stabilization energies (ASE) substituent effect energy (SESE). Other descriptors π‐electron delocalization (HOMA NICS, NICS(1) zz ) also estimated. The SESE ASE values correlated well with one another as constants. Much worse correlations constants found for other aromaticity...

An application of quantum chemical modeling allowed us to investigate a substituent effect on σ and π electron structure ring the nitro group in series meta- para-X-substituted nitrobenzene derivatives (X = NMe2, NHMe, NH2, OH, OMe, Me, H, F, Cl, CF3, CN, CHO, COMe, CONH2, COOH, NO2, NO). The obtained pEDA sEDA parameters (the π- σ-electron characteristics given planar fragment system by summation σ-orbital occupancies, respectively) NO2 benzene reveal impact substituents their mutual...

The development of efficient methods for facilitating N–C(O) bond activation in amides is an important objective organic synthesis that permits the manipulation traditionally unreactive amide bonds. Herein, we report a comparative evaluation series cyclic as activating groups cross-coupling. Evaluation N-acyl-imides, N-acyl-lactams, and N-acyl-oxazolidinones bearing five- six-membered rings using Pd(II)–NHC Pd–phosphine systems reveals relative reactivity order N-activating Suzuki–Miyaura...

In the crystal structure of title compound, C14H11FN2O2, molecule is centrosymmetric. The F atom disordered over four positions, on two ortho positions each ring, with occupancies 0.287:0.213 (5). structure, mol­ecules are linked by inter­molecular N—H⋯O and C—H⋯O hydrogen bonds.

X-ray analysis of N-(4-fluorophenyl)-1,5-dimethyl-1H-imidazole-4-carboxamide 3-oxide reveals the temperature-dependent polymorphism associated with crystallographic symmetry conversion. The observed crystal structure transformation corresponds to a reduction from I41 /a (I) P43 (II) space groups. phase transition mainly concerns subtle but clearly noticeable reorganization molecules in space, individual left almost unchanged. Hirshfeld surface shows that various intermolecular contacts play...

The first report on crystal and molecular structure of 3,6-diiodo-9-ethyl-9H-carbazole is presented. Experimental room-temperature X-ray 13C chemical shift studies were supported by advanced theoretical calculations using density functional theory. nuclear magnetic shieldings predicted at the non-relativistic relativistic level theory zeroth-order regular approximation. Theoretical shifts carbons C3 C6, directly bonded to iodine atoms, produced a reasonable agreement with experiment (initial...

The influence of a solvent on the substituent effect (SE) in 1,4-disubstituted derivatives benzene (BEN), cyclohexa-1,3-diene (CHD), and bicyclo[2.2.2]octane (BCO) is studied by use polarizable continuum model method. In all X-R-Y systems for functional group Y (NO2, COOH, OH, NH2), following substituents X have been chosen: NO2, CHO, H, NH2. characterized charge active region (cSAR(X)), stabilization energy (SESE), constants σ or F descriptors, groups cSAR(Y), whereas π-electron...