Gravar-mail: Crystal structure of bis­(μ(2)-4-tert-butyl-2-formyl­phenolato)-1:2κ(3) O (1),O (2):O (1);3:4κ(3) O (1),O (2):O (1)-bis­(4-tert-butyl-2-formyl­phenolato)-2κ(2) O (1),O (2);4κ(2) O (1),O (2)-di-μ(3)-methoxido-1:2:3κ(3) O;1:3:4κ(3) O-di-μ(2)-methoxido-1:4κ(2) O;2:3κ(2) O-tetra­copper(II)