Chemical Transformations of (2,3,9,10-Tetramethyl-1,4,5,7,8,11,12,14-octa-azacyclotetradeca-1,3,8,10- tetraenato)cobalt(II) Perchlorate
Journal
Journal of the Chinese Chemical Society
Journal Volume
43
Journal Issue
3
Pages
261-276
Date Issued
1996
Author(s)
Abstract
The monomeric octa-aza bis-α-diimine macrocyclic complex [CoII(C10H28N8)(H2O) 2](ClO4)2 I, undergoes various reactions on the macrocyclic ligand. Reaction of complex I with triethylamine in double molar proportions, followed by slow aerial oxidation, produces a molecular dimeric complex [CoII(C10H14N8)]2, III, and a novel Co(I) complex [CoIC10H19N8)], IV. Complex III is a staggered cofacial dimer with a cobalt-cobalt bond length 2.86(1) Å. The macrocyclic ligand of the complex contains an α-diimine function in each five-membered chelate ring, and a three-atom N-C-N- delocalized system in each six-membered chelate ring. Complex IV has the 5-5-6-6 chelate arrangement because one α-diimine moiety is rearranged to a syn-anti configuration. In the structure, the two fused six-membered chelate rings are fully conjugated and the two fused five-membered rings are saturated. However, when complex I reacts with excess triethylamine under the similar conditions, a dimeric complex of another type, [CoII(C10H16N8)]2, II, was generated, in which one N-N bond of the macrocyclic ligand is broken. Complex IV can be isolated also from the reaction of complex I with excess hydrazine, followed by slow aerial oxidation. When hydrazine in double molar proportions was used, complex [CoI(C10H17N8)(NHNH)] V, which contains a coordinated diazene ligand, was obtained. Only one six-membered chelate ring of complex V is deprotonated and oxidized to form a three-atom N-C-N- delocalized system. The structures of octa-aza complexes I-V are determined by X-ray crystallography: I, orthorhombic, C mca, a = 11.646(4), b = 17.049(3), c = 10.706(3) Å, Z = 4, R = 0.045, Rw = 0.047, based on 1024 reflections with I > 2σ(1); II, monoclinic, P 21/c, a = 9.814(3), b = 22.583(6), c = 14.632(9) Å, β = 98.90(5)°, Z = 4, R = 0.085, Rw = 0.101, based on 2033 reflections with I > 2σ(I); III, tetragonal, P 4/nmm, a = 15.614(3), c = 6.498(2) Å, Z = 4, R = 0.081, Rw = 0.115, based on 340 reflections with I > 2σ(I); IV, orthorhombic, P bca, a = 8.484(1), b = 16.662(3), c = 18.760(2) Å, Z = 8, R = 0.029, Rw = 0.024, based on 1441 reflections with I > 2σ(I); V, monoclinic, P 21/m, a = 7.892(3), b = 11.713(6), c = 9.326(4) Å, β= 108.03(3), Z = 2, R = 0.047, Rw = 0.056, based on 948 reflections with I > 2σ(I).
SDGs
Type
journal article