Solids linkage isomerization

Boldyreva EV (2001) Structural aspects of intramolecular solid-state linkage isomerization in Co(III) pentaammine nitro/nitrito complexes. Russ J Coord Chem 27 1-28... 

Masciocchi N, Kolyshev A, Dulepov V, Boldyreva E, Sironi A (1994) Study of the linkage isomerization [Co(NH3)5N02]Bt2 [Co(NH3)50NO]Br2 in the solid state by X-ray powder diffraction. Inorg Chem 33 2579-2585... 

Numerous additional examples of linkage isomerization in solids have been reported.13 Most studies have focused on elucidating the relative roles played by steric and electronic effects in determining the bonding mode of the nitrite or thiocyanate ligand. Interestingly, the bonding mode of thiocyanate has been found to be subject to counter-ion control in the solid state.20... 

Ab initio SCF-MO calculations327 and Hartree-Fock-Slater studies328 predict that the polarization of coordinated N2 will be Ru—N—N. Bands in the vibrational spectrum have been assigned329,330 to the N=N and Ru—N(N2) stretching modes. The frequency and intensity of rN=N are found to be dependent upon counterion and solvent, due to electrostatic interactions in solution.188,331 Mossbauer and 15N NMR studies on [Ru(NH3) N2]2+ have been reported.270 120,332,333 Linkage isomerism of coordinated N2 has been detected in the solid state (t1/2 = 2 1 days at 22°C in the dark) and solution (t1/2 = 2h at 25°C),318 a weak 7i-bonded intermediate being postulated318 (equation 34). 

The spontaneous isomerization from the nitrito (—ONO) to the nitro (—N02) pentaammine-rhodium(III) complex has been well studied, and compared to the isomerizations of the analogous Co, Ir and Cr complexes. Isomerization was shown to occur in both the solid state and, about an order of magnitude more rapidly, in aqueous solution.517 The volume of activation (AF ) in aqueous solution is comparable for [M(NH3)5ONO]2+ (M = Co, Ir and Rh, AF = —6.7, —5.9 and — 7.4 + 4 cm3 mol-1 respectively), which is consistent with the anticipated intramolecular isomerization.584 The linkage isomerization is catalyzed by OH-,585 and by Hg2+, 5B6 In alkaline solution, the linkage isomerization of nitritopentaamminerhodium(III) obeys the rate expression rate =... 

High photolability also is noted for L = CHjCN or Nj however, in these cases NHj labilization is smalF. A different situation is noted for L = SOj. Low-T photolysis of solid tranS lRuCNHjj CKSOjjjCl at 365 nm leads to linkage isomerization of the S-coordinated SOj group to the h -structure ... 

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