A new class of low-spin cobalt(II) chelates. Molecular structure and properties of bis(1-ethyl-3-phenyltriazene-1-olato)cobalt(II) and related complexes

trans-Bis{2-[1-(hydroxyimino)ethyl]phenolato}cobalt(II)

“…In the title compound, which is isostructural with the corresponding nickel(II) (Hatzidimitriou et al, 1997) and copper(II) (Zhou et al, 1985) complexes, the geometry of the cobalt(II) ion is best described as distorted square-planar. The Co-N bond lengths of 1.889 (3) and 1.892 (3) Å are in agreement with the corresponding distances found in other four-coordinated Co complexes (Fachinetti et al, 1979;Rudolf et al, 1988). The Co-O bond lengths are slightly shorter than those found in other structures (Horrocks et al, 1982;Larkworthy & Povey, 1983).…”

Influence of Ligand Substitution Pattern on Structure in Cobalt(II) Complexes of Bulky N,N′‐Diarylformamidinate N‐Oxides

“…In one other case, the stabilization of the square‐planar geometry at the Co centre is assisted by two intramolecular interactions of the X–H ··· Co type 19. This leaves only three other types of N , O ‐ligands, except the AMOXs, able to stabilise the square‐planar geometry of cobalt(II) bis(chelates) with five‐membered chelate rings: α‐imino alkoxide,11 carbohydrazide14e and triazene 1‐oxide derivatives 12c…”

Geometry and Spin Change at the Heart of a Cobalt(II) Complex: A Special Case of Solvatomorphism

“…[c] 2 – 4 : Co(L) 2 , L=amidine‐oxide‐type 7. [d] Compound 5 : Co(L) 2 , L=triazene 1‐oxide‐type (GESTED) 20. [e] Compound 6 : Co(L) 2 , L= o ‐aminophenol‐type (FESFAL) 21.…”

“…The participation of the Oa toms in hydrogenbondingi nteractions lowers their p-donationc haracter and combined with the overall packing interactions contributes to the stabilizationo ft he square-planar form of 1.F urther examination of the packing for 1-green also shows non-classical intermolecular interactions of H···pC(sp 2 )a nd pC(sp 2 )···pC(sp 2 ) [7] [d] Compound 5: Co(L) 2 ,L = triazene 1-oxide-type( GESTED). [20] [e] Compound 6:C o(L) 2 ,L = o -aminophenol-type( FESFAL). [21] [f] Compound 7:C o(L) 2 ,L = a -imino alkoxidetype (GIFJIQ).…”