Search results for "coupling constant"
showing 10 items of 262 documents
Tetramethylditin complexes: A general method for the preparation of a class of compounds with an unusual tintin bond
1980
Abstract The preparation and physical and spectroscopic properties of eight compounds of the type Me4Sn2X2 (X O2CR, S2CNR2, S2P(OR)2) are described, starting from Me4Sn2Cl2. The spectroscopic data indicate that X functions as an isobidentate ligand. The tintin coupling constants are extremely large (ca. 11–15 kHz), and can be correlated with the pKa values of the corresponding acids HX.
Die kopplungskonstanten nJ(SnC) und n+1J(SnH) ineinigen verbindungen mit der tetramethyldizinngruppe
1977
Abstract Comparison of data on seven compounds containing the group tetramethylditin shows a variation in the coupling constants depending on the lone pair electrons of the substituents.
EXTENDED HÜCKEL MOLECULAR ORBITAL CALCULATION OF THE TEMPERATURE DEPENDENCE OF THE QUADRUPOLE SPLITTING OF [Fe(H2O)6] SiF6 AND KFeCl3
1976
A number of papers have appeared in which the temperature dependence of the quadrupole splitting has been treated, whereby covalency effects have been considered by introducing the orbital reduction factor k, with k ranging from 1.-0.7. There are, however, two problems : (1) k is unisotropic if the symmetry is lower than cubic, (2) the spin orbit coupling of the ligand electrons are usually neglected. These two problems have been treated here by using SCCEHMO [1] calculations on two examples, [Fe(H2O)6]SiF6 and KFeCl3, which have been previously delt with by other authors using ligand field theory [2, 3]. For both compounds the differences between the measured and the calculated quadrupole …
Complete basis set B3LYP NMR calculations of CDCl3solvent's water fine spectral details
2008
The assignment of singlet at 1.55 ppm and the 1:1:1 triplet at 1.519 ppm to H2O and HOD in the 400 MHz 1H NMR spectrum of CDCl3 solvent were supported by complete basis set (CBS) GIAO-B3LYP calculated chemical shift and the CBS B3LYP estimated 2J(D,H) spin–spin coupling constant (SSCC). The CBS fitting of B3LYP/cc-pCVxZ and B3LYP/pcJ-n predicted SSCC values, the accurate value of 2J(D,H) = − 1.082 ± 0.030 Hz of HOD in chloroform-d1 and the H/D isotopic shift of 0.0307(1) ppm were reported for the first time. The agreement between CBS B3LYP predicted chemical shift, spin–spin values and experiment was good. Copyright © 2008 John Wiley & Sons, Ltd.
Theoretical prediction of structural, vibrational and NMR parameters of plastic optical fiber (POF) material precursors. Cis and trans perhydro- and …
2014
Abstract Density functional theory (DFT) prediction of cis and trans perhydro- and perfluoro-2-methylene-4,5-dimethyl-1,3-dioxolanes structure, supported by vibrational analysis and calculation of multinuclear isotropic nuclear magnetic resonance (NMR) shieldings and indirect spin–spin couplings (SSCCs) was performed. The performance of the used methodology was verified on 1,3-dioxolane selected as model compound. The structures of hydrogenated and fluorinated monomers of POF materials were calculated using B3LYP and BLYP density functionals combined with 6-311 ++ G(3df,2pd) basis set. The BLYP/6-311++G(3df,2pd) level of theory was suggested for vibrational analysis. Gauge independent atomi…
A Unique Discrete Tetranuclear Cu′–Cu(N-N)2Cu–Cu′ Copper(II) Complex, Built from a μ3-1,2,4-Triazolato-μ-carboxylato Ligand, as an Effective DNA Clea…
2012
The title compound, characterized by means of an X-ray structure analysis, represents an easy example of a noncatena "1 + 2 + 1" tetranuclear copper(II) μ(3)-triazolate compound. [Cu(4)(atc)(2)(dien)(4)(ClO(4))(2)](ClO(4))(2)·2H(2)O (1), where H(2)atc = 5-amino-l,2,4-triazole-3-carboxylic acid and dien = diethylenetriamine = 1,4,7-triazaheptane, contains two copper atoms linked by a double diazinic bridge, each of which is further connected to a third and fourth copper atom (Cu') through the triply bridging triazolato ring and the bidentate carboxylato group of the atc(2-) ligands. The copper-copper distances within the tetranuclear unit are Cu-Cu = 4.059 Å, Cu-Cu' = 5.686 and 6.370 Å, and …
What is the form of muscimol from fly agaric mushroom (Amanita muscaria) in water? An insight from NMR experiment supported by molecular modeling.
2020
ARTYKUŁ Z BADAŃ SPECJALNYCH
On novel magnetic probe for fullerene characterization: Theoretical studies on NMR parameters of free and confined in fullerenes HD and H2 molecules
2015
Chemical characterization and separation of individual fullerenes from a raw reaction mixture need new and efficient tools, including rapid spectroscopic techniques. Recent "molecular surgery" synthesis of endohedral complexes of fullerenes with selected atoms and small molecules has opened a new path for experimental and theoretical studies on structural and spectroscopic properties of these molecular systems. Among them are fullerenes with molecular hydrogen confined within a nanoscale cavity. In this work we report on quantum-chemical prediction of nuclear magnetic shielding (and chemical shift) and indirect spin-spin coupling constant in free HD and H2 molecules, as well as models of co…
1H,13C,17O NMR and IR spectroscopic study of all methyl chloropropanoates
1994
1 H, 13 C and 17 O NMR chemical shifts, n J(H,H) and n J(C,H) spin-spin coupling constants and IR absorption maxima and intensities for the most characteristic bands of methyl propanoate and all eleven chloropropanoic acid methyl esters are reported
Effects of $CP$-violating internucleon interactions in paramagnetic molecules
2020
We demonstrate that electron electric dipole moment experiments with molecules in paramagnetic state are sensitive to $P,T$-violating nuclear forces and other $CP$-violating parameters in the hadronic sector. These experiments, in particular, measure the coupling constant $C_{SP}$ of the $CP$-odd contact semileptonic interaction. We establish relations between $C_{SP}$ and different $CP$-violating hadronic parameters including strength constants of the $CP$-odd nuclear potentials, $CP$-odd pion-nucleon interactions, quark-chromo EDM and QCD vacuum angle. These relations allow us to find limits on various $CP$-odd hadronic parameters.