The crystal structure of bis­[(E)-4-bromo-2-({[2-(pyridin-2-yl)eth­yl]imino}­meth­yl)phenol]nickel(II) bis­[(E)-4-bromo-2-({[2-(pyridin-2-yl)eth­yl]imino}­meth­yl)phenolato]nickel(II) bis(perchlorate) methanol monosolvate, a structure containing strong inter-species hydrogen bonds

The title compound, [Ni(C14H12BrN2O)2][Ni(C14H13BrN2O)2](ClO4)2·CH3OH consists of two mononuclear ([Ni(HL)2]2+ and [NiL2]) complex mol­ecules linked by strong hydrogen bonding [O⋯O separations of only 2.430 (5) A], which is the shortest reported to date for such species. In one of the complexes, both the coordinated phen­oxy groups retain their protons and thus this is the cationic equivalent species of the other complex where both coordinated phen­oxy groups are deprotonated. In addition, perchlorate anions are present for charge balance, as well as methanol solvate mol­ecules. For the neutral NiL2 complex, each 2-ethyl­amine­pyridine arm is disordered over two equivalent conformations with occupancies of 0.750 (8):0.250 (8). The perchlorate anion is disordered over two equivalent conformations with occupancies of 0.602 (8):0.398 (8). The perchlorate ions also link to the H atoms on the methanol methyl and hydroxyl groups. These inter­actions link the moieties into a complex three-dimensional array. The crystal studied was refined as a two-component twin.