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.

Spin Spin Interactions in Polynuclear Nickel(II) Complexes. a Magnetic and Structural Study of Binuclear Nickel(II) Complexes of Enolic 1,3,5-Triketonates

1986 ◽  
Vol 39 (8) ◽  
pp. 1249 ◽  
Author(s):  
PDW Boyd ◽  
KS Lee ◽  
M Zvagulis
Keyword(s):  
Marked Decrease ◽  
Nickel Complexes ◽  
Spin Coupling ◽  
Spin Interaction ◽  
Binuclear Copper ◽  
X Ray ◽  
Spin Interactions ◽  
Spin Spin Coupling ◽  
Antiferromagnetic Spin ◽  
Oxygen Bond

The bulk magnetic susceptibilities of the binuclear nickel(II) complexes of the 1,3,5-triketonates from diethyl (2-oxocyclopentane- 1,3-diyl) bisglyoxylate (H2ecg) (1) and diethyl 2,4,6-trioxoheptanedioate (H2decg) (2) have been measured over the temperature range 6-300 K. Antiferromagnetic spin-spin coupling is observed in each case with Neel temperatures in the range 45-65 K. The X-ray crystal structure of [Ni( ecg )( py )2]2.( py ) has been solved. The complex crystallizes with one pyridine of solvation in the space group Pī [a 10.507(1), b 13.384(1), c 9.992(1) Ǻ, α 103.004(9), β 115.867(9), β 86.857(10)°, Z = 1]. The molecule is binuclear with two coplanar triketonate dianions bridging the two six-coordinate nickel atoms through a di-μ-oxo linkage [Ni-Ob-Ni angle 102.0(1)°]. Two pyridine molecules and four triketonate oxygen atoms are bound to each nickel atoms. Magnetostructural correlations are presented in comparison with binuclear copper(II) 1,3,5-triketonates. The marked decrease in spin-spin interaction in the nickel complexes is attributed to increasing metal-bridging oxygen bond lengths that decrease the efficacy of the σ antiferromagnetic pathway xy||Ob||xy and contributions from the ferromagnetic xy||Ob||z2 pathway.

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.

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.

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
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