Spin-Spin Coupling in Binuclear Complexes. III. The Magnetic Properties of Copper Salts of Substituted Benzoic Acids

1966 ◽  
Vol 5 (11) ◽  
pp. 1855-1858 ◽  
Author(s):  
William E. Hatfield ◽  
Carol S. Fountain ◽  
Robin Whyman
Keyword(s):  
Magnetic Properties ◽  
Spin Coupling ◽  
Binuclear Complexes ◽  
Benzoic Acids ◽  
Copper Salts ◽  
Substituted Benzoic Acids ◽  
Spin Spin Coupling

N-Substituted salicylaldimine complexes of iron(III). II. Magnetic properties

1968 ◽  
Vol 21 (6) ◽  
pp. 1517 ◽  
Author(s):  
den Bergen A van ◽  
KS Murray ◽  
BO West
Keyword(s):  
Magnetic Properties ◽  
Schiff Base ◽  
Spin Coupling ◽  
Coupling Mechanism ◽  
Ferric Ion ◽  
Binuclear Complexes ◽  
Magnetic Susceptibilities ◽  
Mononuclear Complexes ◽  
Bulk Susceptibility ◽  
Spin Spin Coupling

The magnetic susceptibilities of iron(111) N-substituted salicylaldimine complexes of types Fe(sal-XR)3, Fe(sal-NR)2X, [Fe(salH-KR)2X]X, (X = Cl, Br), and [Fe(sal-NR)2]2O have been measured over the temperature range 90-300�K.? The mononuclear complexes exhibit normal high-spin (S = 5/2), Curie-Weiss behaviour. The binuclear oxygen-bridged complexes show antiferromagnetic behaviour and the results have been analysed using the spin-spin coupling mechanism. The exchange interaction is found to be independent of the nature of the N-substituent on the Schiff base. It appears that bulk susceptibility measurements alone cannot unambiguously specify the formal spin state of the ferric ion in these binuclear complexes.

Binuclear and mononuclear nickel(II) and zinc(II) complexes of the tetradentate ligand 1,4-di(2′-pyridyl)aminophthalazine

1980 ◽  
Vol 58 (3) ◽  
pp. 221-228 ◽  
Author(s):  
James Alfred Doull ◽  
Laurence Kenneth Thompson
Keyword(s):  
Nickel Complexes ◽  
Zinc Complexes ◽  
Spin Coupling ◽  
Binuclear Complexes ◽  
Antiferromagnetic Exchange ◽  
Tetradentate Ligand ◽  
Metal Ratio ◽  
Spin Spin Coupling ◽  
Hydroxy Groups

Previous studies with the title ligand, PAP, have shown a predominance of binuclear complexes with cobalt and copper in which the ligand-to-metal ratio is 1:2. The nickel complexes produced are more varied in composition; e.g., 1:2 binuclear systems [PAPNi2X(OH)(H2O)4]X2 (X = Cl, Br); 1:1 binuclear systems [PAP2Ni2(H2O)4]X4 (X = Cl, Br), [PAP2Ni2(NCS)3]NCS, [PAP2Ni2(OH)I2]I•2H2O, [PAP2Ni2(OH)(H2O)2]X3 (X = ClO4, BF4, I); and 2:1 mononuclear systems [(PAPH)2Ni(H2O)2]X4 (X = I, BF4). Zinc forms both mononuclear, [PAPZnX2]•H2O (X = Br, I), and a 1:1 binuclear system, [PAP2Zn2Cl4]. Triple bridges are suggested between the nickel atoms in all binuclear systems involving bridging hydroxy groups. Weak antiferromagnetic exchange is observed (−J < 10 cm−1) in two binuclear nickel complexes, which is enhanced in the presence of a hydroxy bridge. Spin–spin coupling is assumed to occur via a superexchange mechanism. In all cases nickel appears to be six-coordinate while for the zinc complexes both four- and six-coordination are observed.

57Fe-15N Spin-Spin Coupling at Natural Abundance of the Isotopes in Binuclear Complexes Fe2(CO)6(μ-RNS) Containing a Sulfimide Bridge

1991 ◽  
Vol 46 (12) ◽  
pp. 1679-1683 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Ēriks Kupče ◽  
Berthold Distler ◽  
Klaus Dirnberger ◽  
Max Herberhold
Keyword(s):  
Magnetic Resonance ◽  
Polarization Transfer ◽  
Natural Abundance ◽  
Spin Coupling ◽  
Binuclear Complexes ◽  
Spin Spin Coupling ◽  
First Time ◽  
Multinuclear Magnetic Resonance

Complexes of the type Fe2(CO)6(μ-RNS) [R = H (la), tBu (lb), SiMe3 (lc), Si'BuMe2 (1d), SnMe3 (le)] have been studied by multinuclear magnetic resonance (1H13C, 14C, 14N, 15N, 17O, 29Si, 119Sn) with emphasis on natural abundance 15N NMR measurements. By application of various polarization transfer techniques 1J(57Fe15N) (6.1 Hz) in la has been determined for the first time, together with the isotope-induced shift 1Δ34/32S (-36 ppb). Compound ld has been prepared via the reaction between Me2tBuSiCl and Fe2(CO)6(μ-NaNS) (lf), available from la and sodium.

Spin-spin coupling in copper(II) complexes of Pentane-2,4-dione

1974 ◽  
Vol 27 (9) ◽  
pp. 1843 ◽  
Author(s):  
CG Barraclough ◽  
RW Brookes ◽  
RL Martin
Keyword(s):  
Magnetic Properties ◽  
Liquid Nitrogen ◽  
Spin Coupling ◽  
Spin Spin Coupling ◽  
Binuclear Unit

A number of complexes in the series Cu(acac)(X), where X = OMe-, OEt-, OCH2Ph-, N3- and pz- (the pyrazolate anion), have been prepared and their magnetic properties determined down to liquid nitrogen temperatures. Also reported is the complex Cu2(acac)2(OH)(pz). In each case, the magnetism is interpreted in terms of spin coupling within a binuclear unit. All coupling is antiferromagnetic in nature, except for X = N3- which appears to be weakly ferromagnetic.

Spin-Spin Coupling in Binuclear Complexes

1964 ◽  
Vol 86 (18) ◽  
pp. 3888-3889 ◽  
Author(s):  
William E. Hatfield ◽  
John S. Paschal
Keyword(s):  
Spin Coupling ◽  
Binuclear Complexes ◽  
Spin Spin Coupling

Vibrational and thermal averaging of the indirect nuclear spin-spin coupling constants of CH4, SiH4, GeH4 and SnH4

1997 ◽  
Vol 91 (5) ◽  
pp. 897-907 ◽  
Author(s):  
SHEELA KIRPEKAR ◽  
THOMAS ENEVOLDSEN ◽  
JENS ODDERSHEDE ◽  
WILLIAM RAYNES
Keyword(s):  
Nuclear Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

Kinetics and Mechanism of Decomposition of 1,3-Bis(4-methylphenyl)triazene Catalyzed with Substituted Benzoic Acids in 25% Aqueous Methanol-General or Specific Catalysis?

1994 ◽  
Vol 59 (9) ◽  
pp. 2029-2041
Author(s):  
Oldřich Pytela ◽  
Taťjana Nevěčná
Keyword(s):  
Benzoic Acids ◽  
Hammett Equation ◽  
Aqueous Methanol ◽  
Mechanism Of Decomposition ◽  
Kinetics Of Decomposition ◽  
Independent Variable ◽  
Amino Derivatives ◽  
Substituted Benzoic Acids ◽  
The Individual ◽  
Kinetics Of

The kinetics of decomposition of 1,3-bis(4-methylphenyl)triazene catalyzed with 13 substituted benzoic acids of various concentrations have been measured in 25 vol.% aqueous methanol at 25.0 °C. The rate constants observed (297 data) have be used as values of independent variable in a series of models of the catalyzed decomposition. For the catalytic particles were considered the undissociated acid, its conjugated base, and the proton in both the specific and general catalyses. Some models presumed formation of reactive or nonreactive complexes of the individual reactants. The substituent effect is described by the Hammett equation. The statistically best model in which the observed rate constant is a superposition of a term describing the dependence on proton concentration and a term describing the dependence on the product of concentrations of proton and conjugated base is valid with the presumption of complete proton transfer from the catalyst acid to substrate, which has been proved. The behaviour of 4-dimethylamino, 4-amino, and 3-amino derivatives is anomalous (lower catalytic activity as compared with benzoic acid). This supports the presumed participation of conjugated base in the title process.

Kinetic study of hydrolysis of benzoates. part xxvii. ortho substituent effect in alkaline hydrolysis of phenyl esters of substituted benzoic acids in aqueous Bu4NBr

2009 ◽  
Vol 74 (1) ◽  
pp. 29-42 ◽  
Author(s):  
Vilve Nummert ◽  
Mare Piirsalu ◽  
Signe Vahur ◽  
Oksana Travnikova ◽  
Ilmar A. Koppel
Keyword(s):  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Pure Water ◽  
Substituent Effects ◽  
Benzoic Acids ◽  
Resonance Effects ◽  
The Media ◽  
Substituted Benzoic Acids ◽  
Hydrolysis Of ◽  
Ortho Substituent

The second-order rate constants k (in dm3 mol–1 s–1) for alkaline hydrolysis of phenyl esters of meta-, para- and ortho-substituted benzoic acids, X-C6H4CO2C6H5, have been measured spectrophotometrically in aqueous 0.5 and 2.25 M Bu4NBr at 25 °C. The substituent effects for para and meta derivatives were described using the Hammett relationship. For the ortho derivatives the Charton equation was used. For ortho-substituted esters two steric scales were involved: the EsB and the Charton steric (υ) constants. When going from pure water to aqueous 0.5 and 2.25 M Bu4NBr, the meta and para polar effects, the ortho inductive and resonance effects in alkaline hydrolysis of phenyl esters of substituted benzoic acids, became stronger nearly to the same extent as found for alkaline hydrolysis of C6H5CO2C6H4-X. The steric term of ortho-substituted esters was almost independent of the media considered. The rate constants of alkaline hydrolysis of ortho-, meta- and para-substituted phenyl benzoates (X-C6H4CO2C6H5, C6H5CO2C6H4-X) and alkyl benzoates, C6H5CO2R, in water, 0.5 and 2.25 M Bu4NBr were correlated with the corresponding IR stretching frequencies of carbonyl group, (ΔνCO)X.

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