Ethyl 4-[2-(3,5-dimethyl-4-oxo-2,6-diphenyl­piperidin-1-yl)-2-oxoeth­yl]piperazine-1-carboxyl­ate

In the title compound, C28H35N3O4, the piperidine ring adopts a boat conformation while the piperazine ring adopts a chair conformation with an equatorial orientation of the phenyl groups. The dihedral angle between the mean planes of the benzene rings is 74.14 (8)°. The mol­ecular conformation is stabilized by a weak intra­molecular C—H⋯N inter­action and the crystal packing is stabilized by weak inter­molecular C—H⋯O inter­actions

Synthesis, crystal structure, DFT and Hirshfeld surface analysis of 4-fluoro-N-(1,3-dioxoisoindolin-2-yl)benzamide

The 4-fluoro-N-(1,3-dioxoisoindolin-2-yl)benzamide was synthesized by the reaction of 4-fluorobenzohydrazide with phthalic anhydride in acetic acid. The compound was characterized by analytical instruments like FT-IR and NMR. The three-dimensional structure of the title compound was further confirmed by single-crystal X-ray diffraction study. In addition to the experimental study, theoretical calculations were performed to explore the molecular structure in order to analyze experimental and theoretical findings. The title compound crystallizes in the monoclinic space group P21/n as determined by the X-ray diffraction investigation, crystal data for C15H9FN2O3·H2O: a = 14.094(6) Å, b = 7.248(3) Å, c = 14.517(6) Å, β = 105.116(14)°, V = 1431.6(10) Å3, Z = 4, T = 298(2) K, μ(MoKα) = 0.112 mm-1, Dcalc = 1.402 g/cm3, 37521 reflections measured (4.684° ≤ 2Θ ≤ 60.6°), 4225 unique (Rint = 0.0517, Rsigma = 0.0311) that were used in all calculations. The final R1 was 0.0537 (I > 2σ(I)) and wR2 was 0.1501 (all data). The N-H···O and O-H···O hydrogen bonds linking molecules in the crystal form a three-dimensional framework structure. The electronic states and molecular properties of the title compound were determined using computational studies, like density functional theory and Hirshfeld surface analysis

β-Iminoenamine-BF2 Complexes: Aggregation-Induced Emission and Pronounced Effects of Aliphatic Rings on Radiationless Deactivation

The synthesis, photophysical, and electrochemical attributes of a novel class of boron difluorides containing an aromatic-fused alicyclic/hetero-alicyclic ring built on a β-iminoenamine chromophoric backbone are reported. The compounds displayed large Stokes shifts (86–121 nm), and were emissive in the solid state. The quantum yields obtained in solution at room temperature were unusually lower by an order of magnitude compared to those in the solid state. Some of the tested compounds displayed aggregation-induced emission (AIE). Single crystal XRD analyses revealed a lack of interplanar π–π interactions, which are presumed to be absent owing to non-planarity of the alicyclic component in the molecule. For most of the studied compounds, time-dependent DFT (TD-DFT) calculations invariably reveal intramolecular charge transfer (π–π*) characteristics with the frontier orbitals concentrated on the boron–nitrogen heterocycle. The participation of boron and fluorine atoms was found to be negligible

Using a novel ortho-para relationship and the para/meta ratio of substituent effects for mechanism elucidation

Rate constants were measured for the oxidative chlorodehydrogenation of (R,S)-2-phenoxypropanoic acid and nine ortho-, ten para- and five meta-substituted derivatives using (R,S)-1-chloro-3-methyl-2,6-diphenylpiperidin-4-one (NCP) as chlorinating agent. The kinetics was run in 50% (v/v) aqueous acetic acid acidified with perchloric acid under pseudo-first-order conditions with respect to NCP at temperature intervals of 5 K between 298 and 318 K, except at the highest temperature for the meta derivatives. The dependence of rate constants on temperature was analyzed in terms of the isokinetic relationship (IKR). For the 20 reactions studied at five different temperatures, the isokinetic temperature was estimated to be 382 K, which suggests the preferential involvement of water molecules in the rate-determining step. The dependence of rate constants on meta and para substitution was analyzed using the tetralinear extension of the Hammett equation. The parameter lambda for the para/meta ratio of polar substituent effects was estimated to be 0.926, and its electrostatic modeling suggests the formation of an activated complex bearing an electric charge near the oxygen atom belonging to the phenoxy group. A new approach is introduced for examining the effect of ortho substituents on reaction rates. Using IKR-determined values of activation enthalpies for a set of nine pairs of substrates with a given substituent, a linear correlation is found between activation enthalpies of ortho and para derivatives. The correlation is interpreted in terms of the selectivity of the reactant toward para- or ortho-monosubstituted substrates, the slope of which being related to the ortho effect. This slope is thought to be approximated by the ratio of polar substituent effects from ortho and para positions in benzene derivatives. Using the electrostatic theory of through-space interactions and a dipole length of 0.153 nm, this ratio was calculated at various positions of a charged reaction center along the benzene C-1-C-4 axis, being about 2.5 near the ring and decreasing steeply with increasing distance until reaching a minimum value of -0.565 at 1.3 nm beyond the aromatic ring. Activation enthalpies and entropies were estimated for substrates bearing the isoselective substituent in either ortho and para positions, being demonstrated that they are much different from the values for the parent substrate. The electrophilic attack on the phenolic oxygen atom by the protonated chlorinating agent is proposed as the rate-determining step, this step being followed by the fast rearrangement of the intermediate thus formed, leading to products containing chlorine in the aromatic ring

A facile synthesis, antibacterial, and antitubercular studies of some piperidin-4-one and tetrahydropyridine derivatives

The raise in clinical significance of multidrug-resistant bacterial pathogens has directed us to synthesize 2,6-diarylpiperidin-4-one and Δ3-tetrahydropyridin-4-ol based benzimidazole and O-arylsulfonyl derivatives. X-ray crystal structure of tetrahydropyridinol (23) confirmed a change in conformation and orientation of substituents upon amide formation. Antibacterial activities evaluated against a wide number of bacterial pathogens (both sensitive and multidrug-resistant) revealed that 19, 27 against Staphylococcus aureus, 27 against Enterococcus faecalis, and 19, 21, 23, and 27 against Enterococcus faecium are significantly good at lowest MIC90 (16 μg/mL). Inhibitory power noticed by 23 against Vancomycin-Linezolid-resistant E. faecalis and 27 against Vancomycin-resistant E. faecium are onefold better than the standard Linezolid and Trovafloxacin drugs, respectively. Moreover, antitubercular activity for the selected compounds against Mycobacterium tuberculosis H37Rv revealed that compounds 23, 24, and 27 expressed onefold improved potency compared to the standard Rifampicin drug

Metal-free triplet phosphors with high emission efficiency and high tunability

Design of highly efficient phosphorescent emitters based on metal- and heavy atom-free boron compounds has been demonstrated by taking advantage of the singlet fission process. The combination of a suitable molecular scaffold and appropriate electronic nature of the substituents has been utilized to tailor the phosphorescence emission properties in solution, neat solid, and in doped PMMA thin films

Nickel catalyzed synthesis of 4,4′-bichromenes/4,4′-bithiochromenes and their Atropisomerism

4,4′-bichromenes and 4,4′-bithiochromenes have been synthesized by a Ni catalyzed homocoupling method and their Atropisomeric behavior has been studied