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1678160 
Journal Article 
Spontaneous and base-catalyzed nitrito to nitro linkage isomerization of trans-[Co(NH3)(4)(NH2CH3)ONO](2+) complex 
Bozoglian, F; Queirolo, M; Sienra, B 
1998 
1 
Polyhedron
ISSN: 02775387 
17 
20 
3551-3556 
WOS:000076844400010 
The nitrito ion trans-[Co(NH3)(4)(NH2CH3)ONO](2+) rearranges to its nitro form trans-[Co(NH3)(4) (NH2CH3)NO2](2+) in aqueous base according to the rate law k(obs) = k(s) + k(bc)[OH-]. At mu = 1.0 M, 25 degrees C k(s) = 1.01 x 10(-4) s(-1) Delta H-s* = 98 kJ mol(-1); Delta S-s* = 7 JK(-1); k(bc) = 3.3 x 10(-2) M(-1)s(-1); Delta H-bc* = 121 kJ mol(-1); Delta S-bc* = 132 JK(-1) mol(-1). The base-catalyzed isomerization proceeds enterely via an intramolecular conjugate-base mechanism. The reaction is fully retentive and trans-[Co(NH3)(4)(NH2CH3)NO2](2+) is the only species that could be detected by H-1 nmr after the reaction was completed. The results are discussed in the light of the reaction mechanisms proposed so far and in relation to the normal substitution chemistry of pentaammine-cobalt(III) complexes. (C) 1998 Elsevier Science Ltd. All rights reserved. 
nitrito ion; nitro linkage isomerization; pentaamminecobalt(III) complexes