High spin complex

SCHEME 9.R.4 Different electron occupancy patterns when there are six electrons in the d-orbitals in the case of a large splitting gap (left) versus a small splitting gap (right). When the gap is small, four of the electrons occupy solo four of the d-orbitals and form a high-spin magnetic complex with four identical (parallel) unpaired spins. 

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Tris(2,4-pentanedionato)iron(III) [14024-18-1], Fe(C H202)3 or Fe(acac)3, forms mby red rhombic crystals that melt at 184°C. This high spin complex is obtained by reaction of iron(III) hydroxide and excess ligand. It is only slightly soluble in water, but is soluble in alcohol, acetone, chloroform, or benzene. The stmcture has a near-octahedral arrangement of the six oxygen atoms. Related complexes can be formed with other P-diketones by either direct synthesis or exchange of the diketone into Fe(acac)3. The complex is used as a catalyst in oxidation and polymerization reactions. 

Table 26.6 CFSE values for high-spin complexes of 10 ions...

Electron distribution in low-spin and high-spin complexes of Fe2+. Depending on the magnitude of A , either of two different complexes may be formed by Fez+. 

Strategy First (1) find out how many 3d electrons there are in Fe3+. Now (2) consider how those electrons will be distributed if Hunds rule is followed that corresponds to the high-spin complex. Finally (3) sprinkle as many electrons as possible into the lower three orbitals this is the low-spin complex. 

Give the electron distribution in low-spin and/or high-spin complexes of... 

Heterogeneous Non-uniform composition, 4 catalysis, 305-306 equilibrium, 329-331 High-density lipoprotein, 603 High-spin complex A complex that, for a particular metal cation, has the largest number of unpaired electrons, 419 Hindenburg, 111... 

FIGURE 16.35 (a) A strong-field ligand is likely to lead to a low-spin complex (in this case, the configuration is that of Fe3+). (b) Substituting weak-field ligands is likely to result in a high spin complex. 

The majority of octahedral ferric complexes exhibit simple Curie or Curie-Weiss magnetic behavior (i.e., magnetic susceptibility 1/7. They can be classified as either "high spin or "low spin. In high-spin complexes, the lowest term (ground state) is Aig, which corresponds to the tag eg2 configuration. The low-spin complexes have the Tgg term as... 

The electronic spectra and magnetic susceptibility of [Ni(21)Cl2] were found to be consistent with a five-coordinate high spin complex. This complex has greater antitumor activity against P388 lymphocytic leukemia test system in mice than cobalt(II), copper(II), zinc(II) and platinum(II) complexes of 21 [187],... 

State which of the following octahedral high-spin complexes should be Jahn-Teller distorted. 

Table 17.4 Ligand field stabilization energies for Mn304, Fe304 and Co304. Values for high-spin complexes in all cases except for octahedral Co ...

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