Applications of nuclear quadrupole resonance spectroscopy to metal complexes
TL;DR: In this paper, the NQR spectra of a quadrupole resonance (NQR) was used to estimate the population of the nitrogen donor orbital directed toward the metal ion or other Lewis acid.
About: This article is published in Journal of Molecular Structure.The article was published on 1980-01-01. It has received 5 citations till now. The article focuses on the topics: Nuclear quadrupole resonance & Electric field gradient.
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21 Dec 1981TL;DR: In this article, an experimental and theoretical analysis of the nuclear double resonance (ENDOR) of transition metal complexes with organic ligands is considered from an experimental point of view, including second order effects, transitions probabilities and determination of signs of the magnetic parameters.
Abstract: Electron nuclear double resonance (ENDOR) of transition metal complexes with organic ligands is considered from an experimental and theoretical point of view In the experimental sections, instrumentations used in conventional ENDOR and multiple resonance spectroscopy and in some new double resonance methods are discussed Particular emphasis is placed on various experimental techniques which supplement the conventional ENDOR experiment The different methods are illustrated by a number of applications on transition metal complexes1 In the theoretical sections, the analysis of ENDOR spectra of complex spin systems is described including second order effects, transitions probabilities and determination of signs of the magnetic parameters Some of the approaches used in ENDOR to interpret ligand hyperfine and quadrupole data are outlined
32 citations
TL;DR: In this article, the 11B and 10B nuclear quadrupole resonance spectra of boric acid have been obtained at 77 K, by means of the technique of double resonance by level crossing.
16 citations
15 Mar 2008
TL;DR: The usefulness of NQR spectroscopy in inorganic and organometallic chemistry was discussed in this paper, where the authors mainly reviewed selected applications of halogen (35Cl, 79, 81Br, 127I) NQRs to specific bonding questions and divided these according to whether the halogen or other atoms are (a) single-bonded, (b) single bonded with secondary bonds with other atoms, or (c) bonded to several atoms.
Abstract: The article concerns the usefulness of nuclear quadrupole resonance (NQR) spectroscopy in inorganic and organometallic chemistry. NQR-active nuclei have spin I ≥ 1; those of high enough abundance to be commonly useful are found in the odd-numbered groups of the periodic table. These are tabulated and examples given for each. The number of NQR frequencies observed in a solid-state compound reflects the number of chemically different quadrupolar atoms in the compound and also the number of crystallographically inequivalent atoms; changes in the latter may indicate phase transitions or different polymorphs of a given compound. More commonly, one uses average NQR frequencies for chemically different atoms, and from these average frequencies, derives atomic parameters such as populations of valence orbitals, partial ionic charges, π-bond orders, and covalent bond orders of the quadrupolar atom. The article mainly reviews selected applications of halogen (35Cl, 79, 81Br, 127I) NQR to specific bonding questions in inorganic chemistry, and divides these according to whether the halogen or other atoms are (a) single bonded, (b) single bonded but with secondary bonds with other atoms, or (c) bonded to several atoms. For singly bonded atoms, the applications reviewed include (a1) relativistic effects, (a2) effects of nearby ionic charges on haloacetate ions, (a3) the contrasting effects of nearby ionic charges on halometallate ions, (a4) effects of intramolecular partial charges on chlorines in organosilicon compounds, (a5) cis-and trans- ligand effects in substituted halometallate complexes, and (a6) interpretations of multicentered bonding in trihalide ions. Secondary bonding of single-bonded halogen atoms are reviewed particularly in the cases of (b1) halocarbons as ligands, (b2) chloroacetates and chlorophenolates as chlorine-donor ligands, and (b3) in salts of weakly coordinated halogenated anions. Finally, some illustrations are given of NQR studies of central multicoordinated atoms (for example, transition-metal atoms in complexes).
Keywords:
nuclear quadrupole resonance (NQR) spectroscopy;
quadrupole coupling constant;
asymmetry parameter;
electric field gradient;
relativistic effects;
organosilicon compounds;
cis- and trans- effects;
multicentered bonding;
secondary bonding;
noncovalent interactions;
halocarbons as ligands;
weakly coordinating anions
5 citations
TL;DR: In this paper, the endor measurements on single crystals of CU(II) doped bis (salicylaldoxime) also provide quadrupole data, and the two data are compared.
Abstract: 14N NQR in pure salicylaldoxime is studied at 77 °K. ENDOR measurements on single crystals of CU(II) doped bis (salicylaldoxime) also provide quadrupole data. The two data are compared.
4 citations
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TL;DR: In this paper, all six 14N nuclear quadrupole resonances in imidazole were observed using deuterated samples, the EQR of the deuterium in bond and the first unambiguous identification of the quadrupoles coupling constants at a bi-coordinate N site were obtained.
28 citations
26 citations
9 citations