Pseudotetrahedral C2-symmetrical Co/Zn(II)-achiral Schiff base complexes with Δ/Λ-chirality induction at-metal as a racemic mixture

Polymorphism, mesomorphism and anti-oxidant character of homoleptic bis[(E)-2-(1-((o-ethylphenyl)imino)ethyl)phenolato-κ2-N,O]Ni/Cu(ii) complexes

“…C 2 -symmetric pseudo-tetrahedral Co/Zn( ii ) complexes with the achiral Schiff bases ( E )-2-(1-((X-phenyl)imino)methyl)naphthalen-2-ol (X = p -methyl, o -ethyl), for example, form Δ -M and Λ -M (M = Co, Zn) stereoisomers as a racemic mixture. 31 In contrast, homoleptic Ni/Cu( ii ) complexes of the same ligand (X = p -methyl) present square-planar geometry, as expected from simple ligand field considerations. 32 Similarly, mononuclear Rh(η 4 -cod) Schiff base complexes of ( E )-2-(1-((X-phenyl)imino)methyl)-phenol/-naphthalen-2-ol (X = H, o -ethyl) are also square planar.…”

“…Thermal analysis via differential scanning calorimetry (DSC) was used to probe phase transformation temperatures and the associated enthalpy changes (Δ H ) for 1 , microcrystalline 2 isolated from the reaction mixture, and crystallized samples of 2a and 2b . 24,29,31–33 For the nickel complex 1 , the DSC heating curve showed an endothermic peak at 246 °C (Δ H = −36.24 kJ mol −1 ) assigned to melting a crystalline solid to form isotropic liquid (Fig. 6a); upon cooling, an exotherm is evident at 134 °C (Δ H = +22.35 kJ mol −1 ) assigned to solidification of the isotropic liquid phase.…”