4'-substituted neutral/protonated furfurylidenanilines and trans-styrylfurans are able to exist in two different conformations related to the rotation around the furan ring-bridge double bond. In this work, the equilibrium geometry and the corresponding rotational barrier of the benzene ring for each furan derivative conformation were calculated by DFT methods. The trend and shape of the rotational barrier are rationalized within natural bond orbitals as well as atoms-in-molecules approach. For the corresponding equilibrium geometries, (1)H and (13)C substituent induced shifts (SIS) were calculated and compared with experimental values. Calculated shielding constants are shown to be sensitive to the substituent effect through a linear fit with substituent's Hammett constants. An alternative approach was followed for assessing the effect of substituents over SIS through comparing the differences in isotropic shielding constants with NBO charges as well as with (1)H and (13)C experimental chemical shifts.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1007/s00894-013-1964-z | DOI Listing |
J Mol Model
January 2025
Departamento de Investigación y Desarrollo, ConsultoresAcademicos SpA, Moneda 1137, 8340457, Santiago, Chile.
Context: This study meticulously examines the criteria for assigning electron rearrangements along the intrinsic reaction coordinate (IRC) leading to bond formation and breaking processes during the pyrolytic isomerization of cubane (CUB) to 1,3,5,7-cyclooctatetraene (COT) from both thermochemical and bonding perspectives. Notably, no cusp-type function was detected in the initial thermal conversion step of CUB to bicyclo[4.2.
View Article and Find Full Text PDFDalton Trans
January 2025
Institute of Chemistry, St Petersburg University, Universitetskii pr. 26, 198504 St. Petersburg, Russia.
A series of cyclometalated Au(III) complexes [Au(C^N^C)(C-L-P(O)Ph)] with C^N^C = 2,6-diphenylpyridine and alkynylphosphine oxide ligands (L = no linker, Au1; phenyl, Au2; biphenyl, Au3; naphthyl, Au4; anthracenyl, Au5) were synthesized and fully characterized by spectroscopic methods and single crystal XRD analysis. The complexes obtained exhibit triplet (Au1-Au3) and dual (Au4, Au5) emissions in solution, in the solid phase and in the PMMA film, whose characteristics depend on the linker's nature of the alkynylphosphine oxide ligand. The description of electronic transitions responsible for energy absorption and emission in Au(III) complexes was made on the basis of a detailed analysis of the results of DFT calculations and has shown to involve ILCT, LLCT and MLCT transitions of singlet and triplet nature.
View Article and Find Full Text PDFDalton Trans
January 2025
Consiglio Nazionale delle Ricerche, Istituto per la Sintesi Organica e la Fotoreattività (CNR-ISOF), Via Piero Gobetti 101, 40129 Bologna, Italy.
Hybrid coordination polimers based on AgX (with X = Cl, Br) and 2-, 3-, 4-picolylamine ligands, obtained by means of solvent-free methods, show peculiar luminescence properties that are strongly influenced by their structural motif, which in turn is defined by the adopted isomer of the ligand. A comprehensive study, combining photophysical methods and DFT calculations, allowed to rationalize the emissive behaviour of such hybrid coordination polymers in relation to their crystal structures and electronic properties. By means of luminescence measurements at variable temperatures, the nature of the emissive excited states and their deactivation dynamics was interpreted, revealing XMLCT transitions in the [(AgX)(2-pica)] compounds, a TADF behaviour in the case of 3-pica derivatives, and a dual emission at room temperature for the [(AgX)(4-pica)] family.
View Article and Find Full Text PDFJ Comput Chem
January 2025
Institute of Fundamental Technological Research Polish Academy of Sciences, Warsaw, Poland.
The suitability of a range of interatomic potentials for elemental tin was evaluated in order to identify an appropriate potential for modeling the stanene (2D tin) allotropes. Structural and mechanical features of the flat (F), low-buckled (LB), high-buckled (HB), full dumbbell (FD), trigonal dumbbell (TD), honeycomb dumbbell (HD), and large honeycomb dumbbell (LHD) monolayer tin (stanene) phases, were gained by means of the density functional theory (DFT) and molecular statics (MS) calculations with ten different Tersoff, modified embedded atom method (MEAM), and machine-learning-based (ML-IAP) interatomic potentials. A systematic quantitative comparison and discussion of the results is reported.
View Article and Find Full Text PDFJ Comput Chem
January 2025
Physics Department and CICECO-Aveiro Institute of Materials, University of Aveiro, Aveiro, Portugal.
Lanthanide (Ln) tetrakis complexes, C[Ln(L)], are important for applications due to their high quantum yields, solubility, and stability. Their luminescent properties depend on the structure, particularly the coordination polyhedron, the assessment of computational methods for calculating their structures is paramount. Usually, this assessment uses the RMSD of distances in the [Ln(L)] complex or {LnO} polyhedron between crystallographic and calculated structures.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!