Magnetic and spectroscopic properties

Absorption Spectra of Some Hydroxo-Bridged Ammine and Amine Complexes in Aqueous Solution 

Some representative spectral data are given in Table VI. The spectroscopic properties of /x-hydroxo-/i-peroxo and -hydroxo/x-superoxo dicobalt(III) complexes have recently been reviewed by Fallab and Mitchell (119) and seem reasonably well rationalized in terms of the molecular orbital (MO) models formulated by Lever and Gray (120). The spectra of -hydroxo -/x-peroxo and /i-hydroxo-/i-superoxo complexes of rhodium(III) show features similar to those of the cobalt(III) species (121-124). 

Glerup s model can be extended to many other systems (135,136). For example, an extension of the model has been used to interpret the magnetic properties of di-ji-hydroxo dichromium(III) complexes. It was 

Only a few trihydroxo-bridged chromium(III) complexes have been studied. The cation (metacn)Cr(OH)3Cr(metacn)3+ has J = 128 cm-1 (137, 138), and the corresponding tacd complex has J = 96 cm-1 (98). 

Inelastic neutron scattering experiments have been used to study the ground state splitting of singly bridged dichromium(III) complexes of 

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Nickel(ll) is the only common d ion and its spectroscopic and magnetic properties have accordingly been extensively studied. 

The binuclear iron unit consisting of a (p,-oxo(or hydroxo))bis(p.-carboxylato)diiron core is a potential common structural feature of the active sites of hemerythrin, ribonucleotide reductase, and the purple acid phosphatases. Synthetic complexes having such a binuclear core have recently been prepared their characterization has greatly facilitated the comparison of the active sites of the various proteins. The extent of structural analogy among the different forms of the proteins is discussed in light of their spectroscopic and magnetic properties. It is clear that this binuclear core represents yet another stractural motif with the versatility to participate in different protein functions. 

The tetranuclear complex [Fe20(O2CCH3)2 (tpbn)2 ] 2 recently reported(14) is not an 0x0-iron aggregate according to our definition but comprises two quasi-independent dinuclear p-oxo diiron units. Its spectroscopic and magnetic properties are consistent with this view. 

A third type of trinuclear cluster duplicates the Fe3S stoichiometry that is most accepted for protein-bound 3Fe clusters and in fact appears to be a structural isomer of the 3Fe cluster present in aconitase at least. The [Fe3S (SR) ]ion (3) is obtained by reaction of [Fe(SR) ] " with 1.4 equivalents of sulfur in MeCN, as indicated above (13, 16). It contains a central Fe(III) ligated tetrahedrally by four sulfides that connect it to two terminal Fe(IIl)(SR)2 units. The spectroscopic and magnetic properties of 3 are virtually identical with those of the 3Fe form of aconitase at high pH, but substantially different from those of aconitase under normal physiological conditions (23). Possible structures for the latter that are consistent with available data are shown in Figure 7. 

When KMnO is mixed with MnCl2,4H20 in cone. HCl followed by the addition of [Co(en)3]Cl3 at — 10"C, [Co(en)3][MnCl ],H20 is formed. Spectroscopic and magnetic properties = 4.94 BM at 293 K) have been reported. Polarized crystal spectra of MnClj" have been reported. The results indicate 2, symmetry for (bipH2)[MnCl5] (bipH2 = bipyridinium ion) and symmetry when Mn is doped into (Et N)2lnCl5. ... 

Bpy complexes, osmium, spectroscopic and magnetic properties, 37 329-330 Bpy polymers, osmium, spectroscopic and magnetic properties, 37 330 Bradyrhizobium japonicum, leghemoglobin in, 46 499-500... 

IV. Spectroscopic and Magnetic Properties of Coordination Complexes A. Monomers... 

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