Electronic Parameters Research Articles

Synthesis, Biological Evaluation, and Computational Studies of Schiff's Base Derivatives of 4-(4-Amino-5-Mercapto-4H-1,2,4-Triazol-3-Yl)Benzenesulfonamide as Cathepsin B Inhibitors.

A library of benzenesulfonamide incorporated Schiff's base derivatives of 4-amino-5-mercapto-1,2,4-triazoles 1a-f, 2a-e, and 3a-e has been synthesized and evaluated in-vitro for their inhibition potential against cathepsin B enzyme. All the tested compounds possessed good to excellent anti-cathepsin B activity (40.62%-74.36%) at 10-7m concentrations in comparison with the curcumin (51.20%) taken as reference. Among all, compound 3c has shown the highest activity exhibiting 74.36% inhibition followed by 3e and 3b (69.99% and 68.36% inhibition, respectively). Molecular docking was performed for the most active compound 3c and the reference compound, curcumin, to know their interactions in the active site of the target enzyme and the results obtained were in agreement with the experimental values. Additionally, DFT calculations were also performed to determine the values of electronic parameters including energies of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), HOMO-LUMO energy gap, chemical hardness, chemical softness, chemical potential, electronegativity, and electrophilicity index.

Using the Transversal Admittance to Understand Organic Electrochemical Transistors.

The transient behavior of organic electrochemical transistors (OECTs) is complex due to mixed ionic-electronic properties that play a central role in bioelectronics and neuromorphic applications. Some works applied impedance spectroscopy in OECTs for understanding transport properties and the frequency-dependent response of devices. The transversal admittance (drain current vs gate voltage) is used for sensing applications. However, a general theory of the transversal admittance, until now, has been incomplete. The derive a model that combines electronic motion along the channel and vertical ion diffusion by insertion from the electrolyte, depending on several features as the chemical capacitance, the diffusion coefficient of ions, and the electronic mobility. Based on transport and charge conservation equations, it is shown that the vertical impedance produces a standard result of diffusion in intercalation systems, while the transversal impedance contains the electronic parameters of hole accumulation and transport along the channel. The spectral shapes of drain and gate currents and the complex admittance spectra are established by reference to equivalent circuit models for the vertical and transversal impedances, that describe well the measurements of a PEDOT:PSS OECT. New insights are provided to the determination of mobility by the ratio between drain and gate currents.

Inspecting the structural stability, magneto-opto-electronic, and transport characteristics of half-metallic ferromagnets double perovskite oxide (Sr2MoSbO6): A DFT study

The structural, elastic, mechanical, electronic, thermoelectric, and magnetic properties of the double perovskite Sr2MoSbO6 have investigated in this manuscript using Perdew-Burke-Ernzerhof Generalized Gradient Approximation (PBE-GGA) with an enhanced Trans Blaha modified Becke Johnson potential (TB-mBJ) approach. Through electro-magnetic and elastic exploration, we have determined that this compound is semiconductor, ferromagnetic, and brittle. Strong hybridisation between the Mo and Sr-d orbitals was seen in the Density of states (DOS) results, which, according to their relative quantities, supports the two states' ionic nature. The Mo atoms contribute significantly to the overall magnetic moment, which is 3.0 μB in total. The semiconducting nature of Sr2MoSbO6 is confirmed by the calculation of the overall electronic parameters. Calculations of thermodynamic parameters for temperature ranges of 0–1200 K and pressure ranges of roughly 0–30 GPa show good agreement between theoretical and experimental data. The DFT Boltzmann transport equations have been used to compute thermoelectric properties in relation to temperature and chemical potential. The p-type character of Sr2MoSbO6 is identified by positive values of the Seebeck coefficient. The power factor (PF), Seebeck coefficient (S), figure of merit (ZT), electrical conductivity, and lattice thermal conductivity were also calculated. It was discovered that this perovskite had a merit figure that was almost equal to one, a very high Seebeck coefficient, and strong electrical conductivity—all of which are consistent with its semiconductor nature. These findings suggest a substance with a great deal of promise for thermoelectrical uses. The results are taken into consideration for future experiments and may be future candidates for spintronics applications.

Calculation of Structural, Electronic, Optical, Dynamic and Thermoelectric Properties of Monolayer made of Carbon and Nitrogen

In this research, using the Win2k software based on the Cohen–Sham equations and applying the density functional theory with the help of the full potential linearized augmented plane wave method (FP-LAPW), the dynamic, electronic, optical and thermoelectric parameters of the C5N monolayer have been physically investigated. The results of electronic properties calculations indicate that the C5N monolayer has metallic and nonmagnetic properties. The maximum absorption of higher energies occurs at the energy of 11.98[Formula: see text]eV in the [Formula: see text] direction. In the [Formula: see text] direction, the peaks are evident in the range of the visible light region at energies of 1[Formula: see text]eV and 3[Formula: see text]eV while no peak is observed in the visible light region in the [Formula: see text] direction. In addition, the phonon dispersion diagram is calculated by the linear response approach along the symmetric points for this structure. The outcomes provide no negative modes in the phonon spectrum, expressing that these structures are dynamically in equilibrium. The use of Boltzmann transfer theory with the relaxation time approximation to investigate the thermoelectric properties of the C5N monolayer reveals that the low Seebeck coefficient and the increase of thermal conductivity by increasing temperature leads to a very small ZT for the above monolayer. The minimum value of the Seebeck coefficient at the temperature of 300[Formula: see text]K is −45[Formula: see text][Formula: see text]V/K, and with increasing temperature, it exhibits an upward trend to reach −17[Formula: see text][Formula: see text]V/K under a temperature of 600[Formula: see text]K, meaning that the low value of the Seebeck coefficient (less than 100[Formula: see text][Formula: see text]V/K) is in agreement with the metallic nature of this monolayer. The metallic property of this structure is considered an important feature in fabricating electrodes (batteries).

Correlation Between NMR Coupling Constants and σ-Donating Properties of N-Heterocyclic Carbenes and Their Derivatives.

Is the 1JC-H coupling constant for protonated carbene a relevant measure of its σ-donation ability? This paper addresses this question by comparing calculated 1JC-H values with various experimental and theoretical approaches across a broad spectrum of carbene compounds. We examined Arduengo-type NHCs based on the 2-imidazolylidene scaffold and many other derivatives with modified frameworks, including carbenes with extended, saturated, or conjugated rings, reduced heteroatom stabilization, alternative heteroatoms, permanently charged carbenes, acyclic carbenes, amidocarbenes, and cyclic amino(alkyl/aryl) carbenes, carbodicarbenes and carbodiphosphoranes. Our findings reveal a nuanced relationship between different parameters associated with σ-interaction, such as 1JC-H, Huynh electronic parameter (HEP), σ-donation from ETS-NOCV, and lone pair energy. Notably, the best correlation was observed between 1JC-H and the ETS-NOCV method, particularly for mono- and diaminocarbenes, highlighting the utility of 1JC-H in comparing σ-donation among structurally similar carbene types. However, the use of 1JC-H as a universal measure across all carbene classes appears limited, especially when considering carbenes with significantly different structural frameworks. While HEP is less effective for carbenes with diverse structural backbones, our study suggests that 1JC-H has potential across a broader range of systems. Additionally, the analysis demonstrates that lone pair energy reflects basicity rather than σ-donor ability.

Influence of Pnictogen and Ligand Framework on the Lewis Acidity and Steric Environment in Pnictogen Pincer Complexes.

Pnictogen pincer complexes are a fascinating class of compounds due to their dynamic molecular and electronic structures, and valuable stoichiometric or catalytic reactivity. As recognition of their unique chemistry has grown, so too has the library of pincer ligands employed and pnictogen centres engaged to prepare them. Here we computationally study how the choice of pincer ligand framework and pnictogen influence the electronic and steric outcomes within the complexes obtained. The most relevant electronic parameter is the pnictogen-centred electrophilicity, which has been quantified by fluoride ion affinities and LUMO energies, while the most relevant steric parameter is the crowding around the central pnictogen, which has been quantified by the %Vbur values and visualized using steric maps. The resulting trends are analyzed with reference to binding pocket size, acceptor orbital type, electronic delocalization, π-donor strengths, and heteroatom incorporation. Thus, considering 16 ligand frameworks and 4 heavy pnictogen centres, this study provides a broad-spectrum view of stereo-electronic variation in pnictogen pincer complexes, which, together with a recent study on geometric variation in the same family, provides a substantial dataset to guide future molecular design and reactivity studies.

Investigating the Antiproliferative Activity of Novel 4-Chloro-8-Nitro-1,2-Dihydro-3-Quinoline Acylhydrazones on Human Cervical Cancer Cell Lines.

A new series of acyl hydrazones have been synthesized from 4-chloro-8-nitro-1,2-dihydroquinoline-3-carbaldehyde. These compounds were characterized using various spectroscopic techniques. Density functional theoretical (DFT) studies were conducted to understand the correlation between electronic parameters and biological activity. The biological activity of the compounds was theoretically examined through molecular docking and ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) analysis. The compounds demonstrated high absorption rates and were found to be non-hepatotoxic. Preliminary cytotoxicity screenings against HeLa cell lines identified compound 7 as the most potent, with an IC50 value of 18.8 μM. This compound was further selected for bioimaging studies. The results indicate that compound 7 induces apoptosis at its IC50 concentration, suggesting its potential as an anticancer agent.

Chemoselective Intramolecular Rauhut‐Currier Reaction on a Labile Framework of Enone and Acrylamide: Tricyclohexylphosphine as a Stable and Economical Catalyst

AbstractIntramolecular Rauhut‐Currier (IRC) reaction is an atom‐economical way of making carbocyclic and heterocyclic rings. However, its sensitivity towards electronic and steric parameters limits the reaction and stems the need for further development. Acrylamides have been one such left out of their sensitivity. Herein we report an IRC reaction, using acrylamide as a source of initial enolate. The cyclization has been achieved on a labile and challenging framework, prone to decomposition. Different control experiments have addressed the instability of the precursor. Protocol was further extendable to annulation for benzo analogs. We also report tricyclohexylphosphine (PCy3) as a stable, commercial, and easy‐to‐use nucleophilic catalyst in the field of IRC reactions as compared to earlier well‐established trimethyl and tributyl phosphines. Me3P and Bu3P although useful, are sensitive, prone to oxidation, and need careful handling. The protocol leads to the synthesis of piperidone and dihydroquinolone frameworks. A quick study to test the feasibility of catalyzing the Morita‐Baylis‐Hillman (MBH) reaction by PCy3 was also done successfully, although in moderate yields.

Improved gas sensing properties of copper-doped MoSe2 monolayers: a first-principles study on CO2 and NO2 adsorption

Abstract This paper investigates the impact of copper (Cu)-doped MoSe2 monolayer (ML) on gas sensing properties. The adsorption behaviour of CO2 and NO2 gas molecules on Cu-doped MoSe2 ML is reported and various sensing and electronic parameters such as adsorption energy, charge transfer and recovery time, are computed to delineate the adsorption characteristics and gas sensitivity. In our study, the doped Cu-atom in Se vacant MoSe2 ML shows the adsorption energies to be −1.32 eV (O-orient) and −1.72 eV (C-orient), for CO2, while for NO2, they are −0.879 eV (O-orient) and −1.06 eV (N-orient), respectively. The negative formation energy of −6.62 eV shows the electronic stability of Cu-doped MoSe2 ML and thermal stability, demonstrated by the molecular dynamics study through the Nose-Vervlet Thermostat (NVT) algorithm. Also, significant changes are observed in electronic conductivity and work function upon adsorbed Cu-MoSe2 ML. Lastly, these outcomes illustrate that Cu doping amplifies the capture ability of MoSe2 ML towards gas molecules, fostering improved electron interaction between the substrate surface and gas molecules, consequently enhancing its gas sensing ability.

Observing vibronic coupling in a strongly hydrogen bonded system with coherent multidimensional vibrational-electronic spectroscopy.

The coupled structural and electronic parameters of intramolecular hydrogen bonding play an important role in ultrafast chemical reactions, such as proton transfer processes. We perform one- and two-dimensional vibrational-electronic (1D and 2D VE) spectroscopy experiments to understand the couplings between vibrational and electronic coordinates in 10-Hydroxybenzo[h]quinoline, an ultrafast proton transfer system. The experiments reveal that the OH stretch (νOH) is strongly coupled to the electronic excitation, and Fourier analysis of the 1D data shows coherent oscillations from the low frequency backbone vibrational modes coupled to the νOH mode, resulting in an electronically detected vibronic signal. In-plane low-frequency vibrations at 242 and 386 cm-1 change the hydrogen bond distance and modulate the observed electronic signal in the polarization-selective 1D VE experiment through orientation-dependent coupling with the νOH mode. Resolution of the excitation frequency axis with 2D VE experiments reveals that excitation frequency, detection frequency, and experimental delay affect the frequency and strength of the vibronic transitions observed. Our results demonstrate evidence of direct coupling of the high frequency νOH mode with the S1 ← S0 electronic transition in 10-Hydroxybenzo[h]quinoline (HBQ), and orientation-dependent couplings of the low-frequency 242 and 386 cm-1 modes to the νOH mode and the electronic transition. This demonstration of multidimensional VE spectroscopy on HBQ reveals the potential of using 1D and 2D VE spectroscopy to develop a quantitative understanding of the role of vibronic coupling in hydrogen bonding and ultrafast proton transfer for complex systems.

An improved laser photo-detachment diagnostic for negative ion density measurement

A photo-detachment Langmuir probe is a crucial tool because it gives a point measurement of negative ion density. The detection circuitry of a photo-detachment diagnostic with nanosecond laser pulses is critical for the accuracy of the results. Applying the electromagnetic theory to the design of the photo-detachment system has allowed it to stabilize its frequency response up to ~445 MHz, providing a significantly higher time resolution than in a common photo-detachment circuit setup. A systematic design rule is given in this paper to standardize the proper circuit. The new standard allows comparison between laboratories without concern for electronic parameter differences. The high-time resolution result shows three different peaks in the photo-detached electron current. This paper identified that the first peak is the most correlated to negative-ion density information, and the second and third peaks are related to background electrons interacting with build-up potential.

Preparation, Characterization, In Vitro Biological Evaluation, DFT Calculations, and Molecular Docking Investigations of 1H-Imidazole-2-Carboxylic acid and Histidine-Based Mixed-Ligand Complexes.

Mixed-ligand complexes incorporating 1H-Imidazole-2-Carboxylic acid (IMCA) and Histidine (LHIS) show promise for biomedical and biotechnological applications. This study synthesizes and characterizes FeIMCALHIS, CoIMCALHIS, and NiIMCALHIS coordination compounds using metal chloride salts (FeCl3.6H2O, CoCl2.6H2O, NiCl2.6H2O) in ethanolic solutions. The complexes are characterized by spectroscopic methods (IR, UV-vis, and mass spectra), elemental analysis, conductivity, magnetic, and thermal analysis. Molar conductivity indicates their non-electrolytic nature. UV-vis spectra reveal absorption bands with pathochromic shifts, and electronic spectra show characteristic metal-ligand transitions, indicating their structural configuration and coordination geometry. 3D geometry optimization shows six-coordination around Fe(III) and Co(II) in FeIMCALHIS and CoIMCALHIS, and four-coordination around Ni(II) in NiIMCALHIS. Analysis of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) suggests decreased electron donation ability upon coordination. Electronic structure parameters (HOMO, LUMO, ionization potential, energy gap, electron affinity, chemical potentials, and electronegativity) provide further insights into stability and reactivity. The metal complexes exhibit enhanced antimicrobial, antioxidant, and anti-inflammatory activity compared to individual ligands, with FeIMCALHIS showing notable antimicrobial activity. Molecular docking analysis reveals strong binding interactions with target proteins, highlighting their potential therapeutic applications.

An in-silico study on boronyl-based novel liquid crystalline series

We explore a novel liquid crystalline (LC) series nXB having an alkyl chain length (CnH2n+1) and boronyl group (BO) at terminals using density functional theory. The properties of BO-substituted 2XB molecule are found to be similar to 2CB, a well-known LC compound. Further, this novel compound prefers stacking interaction forming a dimeric complex similar to other LC compounds. These results suggest the potential of BO-substituted compounds to form new LC series. Various electronic parameters of this new nXB series are calculated in the gas phase and solvent effects are also taken into account for n = 1–12. The variation in these parameters clearly reveals the alteration in the trend leading to the odd–even effect, as observed in typical nCB compounds. In particular, the odd–even phenomenon for dipole moment has been discussed in the gas phase as well as in solvents. Thus, our findings predict a novel liquid crystalline series having analogous properties with cyanobiphenyl liquid crystalline series.

Structural characterisation of a cyanomesogen by X-ray diffraction and computational methods

The work reports the structural analysis of a cyanomesogen namely, p-cyanobenzylidene p-nonyloxyaniline belonging to the Schiff base class of compounds. It exhibits a partial bilayer/inter-digitated smectic Ad phase and a nematic phase. Polarising Optical Microscopy (POM) and Differential Scanning Calorimetry (DSC) studies have been carried out to study phase sequence and transition temperatures. Micro-structural parameters, like molecular length, spacing, crystallite size, activation energy and micro-strain, have been estimated and pair correlation function (PCF) studies have been done for exhibited mesophases using the X-ray diffraction technique. The study investigated the surface, electronic and optical properties of a compound by computational studies like Density Functional Theory (DFT) and Hirshfeld surface analysis (HSA) methods using the DFT B3LYP/6-311++G(d,p) level basis set. The results reveal that the polarity associated with the polar groups and alkoxy chain lengths, contributes majorly to the mesomorphic characteristics and stability. The Highest Occupied Molecular Orbitals (HOMO) and Lowest Unoccupied Molecular Orbitals (LUMO) analyses of the DFT optimised molecule give electronic and geometrical parameters, atomic charge distribution, polarisability factors which are used to interpret the characteristics of the mesophases and their suitability for electro-optical and non-linear optical applications of the compound in terms of the predicted data.

Quantitative photothermal investigation of nonradiative recombination parameters in GaAs/InAs(QD)/GaAs quantum dot structures using a three-layer laser beam deflection model

In this paper, we developed a theoretical model for the photothermal deflection technique in order to investigate the electronic parameters of three-layer semiconductor structures. This model is based on the resolution of thermal and photogenerated carrier diffusion-wave equations in different media. Theoretical results show that the amplitude and phase of the photothermal deflection signal is very sensitive to the nonradiative recombination parameters. The theoretical model is applied to one layer of InAs quantum dots (QDs) inserted in GaAs matrix InAs/GaAs QDs in order to investigate the QD density effects on nonradiative recombination parameters in InAs through fitting the theoretical photothermal beam deflection signal to the experimental data. It was found that the minority carrier lifetime and the electronic diffusivity decrease as functions of increasing InAs QD density. This result is also related to the decrease in the mobility from 21.58 to 4.17 (±12.9%) cm2/V s and the minority carrier diffusion length from 0.62 (±5.8%) to 0.14 (±10%) μm, respectively. Furthermore, both interface recombination velocities S2/3 of GaAs/InAs (QDs) and S1/2 of InAs (QDs)/GaAs increase from 477.7 (±6.2%) to 806.5 (±4%) cm/s and from 75 (±7.8%) to 148.1 (±5.5%) cm/s, respectively.

Nonlinear optical parameters and electronic properties of plasma polymerized methyl acrylate thin films

Plasma polymerized methyl acrylate (PPMA) thin films were fabricated on a borosilicate glass substrate at a plasma power of 28 W to study nonlinear optical parameters and electronic properties. X-ray Diffraction analysis confirmed the amorphous nature of the PPMA films, while Attenuated total reflectance Fourier transform infrared spectroscopy indicated monomer fragmentation due to plasma polymerization. Field emission scanning electron microscope images of the films display a water wave-like structure. PPMA films demonstrated thermal stability up to approximately 574 K in both N2 and air environments. The values of direct band gap energies increase from 3.30 to 3.41 eV with increasing film thicknesses, whereas the Urbach energy values show in an opposite manner. The Wemple-DiDomenico model was employed to analyze both the oscillator energies ranging from 5.54 to 6.44 eV and the dispersion energies ranging from 10.56 to 12.89 eV. The static linear refractive index showed typical dispersion behavior, with film thickness conforming to Moss's rule. The nonlinear refractive index and 2nd and 3rd order nonlinear susceptibilities decrease with increasing the studied films. The lattice dielectric constant values exceeded the high-frequency dielectric constant, indicating the presence of lattice vibrations and free carriers. Electronic parameters are fluctuating with increasing film thickness. The observed changes in nonlinear optical parameters and electronic properties highlight the potential of PPMA films for applications in photovoltaic and optoelectronics.

In Silico Design of Novel Piperazine-Based mTORC1 Inhibitors Through DFT, QSAR and ADME Investigations

Mammalian target of rapamycin complex 1 (mTORC1) is an important and promising alternative biological target for the treatment of different types of cancer including breast, lung and renal cell carcinoma. This study contributed to the development of mathematical models highlighting the quantitative structure-activity relationship of a series of piperazine derivatives reported as mTORC1 inhibitors. Various molecular descriptors were calculated using Gaussian 09, Chemsketch, and ChemOffice software. The density funcional theory (DFT) method at the level B3LYP/6-31G+(d, p) was applied to determine the structural, electronic and energetic parameters associated with the studied molecules. The predictive ability of the built models, which is obtained by two methods (MLR and MNLR), showed that the built models are statistically significant. The QSAR modeling results revealed that the six molecular descriptors of lowest unoccupied molecular orbital energy (ELUMO), electrophilicity index (ω), molar refractivity (MR), aqueous solubility (Log S), topological polar surface area (PSA), and refractive index (n) significantly correlated to the biological inhibitory activity of piperazine derivatives. Using QSAR models and in silico pharmacokinetic profiles predictions, five new candidate compounds are selected as potential inhibitors against cancer.

Experimental and computational analysis of poly(4-vinyl pyridine) and polyvinylpyrrolidone as effective corrosion inhibitors for low carbon steel in sulfuric acid

This study investigates the inhibitory effects of poly(4-vinyl pyridine) (P4VP) and polyvinylpyrrolidone (PVP) on the corrosion of low carbon steel (LCSt) in 1 M H2SO4. Protection efficacy (%PE) was measured using mass loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). Results showed %PE values increased with higher polymer concentration and lower temperature. At 450 mg/L, %PE reached 93.13% and 94.19% for P4VP and PVP, respectively. These polymers function as mixed inhibitors, adsorbing onto the LCSt surface per Langmuir’s model as a mode of physical adsorption. EIS indicated that higher polymer concentration increased charge transfer resistance and decreased effective double-layer capacitance. Both P4VP and PVP also reduced pitting corrosion in chloride-containing solutions. Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) optimized the molecular structures of the inhibitors, evaluating electronic parameters such as frontier molecular orbital (FMO) energies, energy gap, softness, hardness, electron transfer fraction, dipole moment, and hyperpolarizability ( β ° ). Monte Carlo (MC) and molecular dynamics (MD) simulations provided insights into adsorption mechanisms, corroborating experimental findings and highlighting the effect of protonation. This comprehensive study enhances our understanding of the relationship between molecular structure and function in polymer inhibitors, improving their application in corrosion protection.

Electronic Descriptor to Identify the Activity of SACs for E-NRR and Effect of BF3 as Electrolyte Ion.

Electrochemical nitrogen reduction reaction (e-NRR) is an eco-friendly alternative approach to generate ammonia under ambient conditions, with very low power supply. But, developing of an efficient catalyst by suppressing parallel hydrogen evolution reaction as well as avoiding the catalysts poisoning either by hydrogen or electrolyte ion is an open question. So, in order to screen the single atom catalysts (SACs) for the e-NRR, we proposed a descriptor-based approach using density functional theory (DFT) based calculations. We investigated total 24 different SACs of types TM-Pc, TM-N3C1, TM-N2C2, TM-NC3 and TM-N4, considering transition metal (TM). We have considered mainly BF3 ion to understand the role of electrolyte and extended the study for four more electrolyte ions, Cl, ClO4, SO4, OH. Herein, to predict catalytic activity for a given catalyst we have tested 16 different electronic parameters. Out of those, electronic parameter dxz↓ occupancy, identified as electronic descriptor, is showing an excellent linear correlation with catalytic activity (R2=0.86). Furthermore, the selectivity of e-NRR over HER is defined by using an energy parameter ▵G*H-▵G*NNH. Further, the electronic descriptor (dxz↓ occupancy) can be used to predict promising catalysts for e-NRR, thus reducing the efforts on designing future single atom catalysts (SACs).

Revisiting Isomerism in Square Planar Palladium NHC Complexes with NacAc Chelators.

Quantifying the donor ability of bidentate ligands in inorganic chemistry is not straightforward, and the Huynh electronic parameter for chelators (HEP2) presents a rare solution to the task. Aiming to extend the ligand scope in this work, the soundness and practicality of HEP2 was further scrutinized with seven stereoelectronically diverse β-ketiminato ("NacAc") chelators using palladium complexes of the type [PdBr(iPr2-bimy)(ArNacAc)] (iPr2-bimy = 1,3-diisopropylbenzimidazolin-2-ylidene). Notably, the unsymmetrical nature of this κ2-N,O ligand family allowed for an intriguing exploration into isomerism in the square planar PdII products, which depends on the N-aryl ortho- and para-substituents based on experimental and theoretical findings. The HEP2 values of both isomeric forms correlate well with the widely used σp Hammett constants, which reinforces the reliability of this modern methodology.