Crystal structure of (((1E,1′E)-(cyclohexane-1,2-diylbis(azanylylidene-κ2N,N′))bis(methanylylidene))bis(2,1-phenylene))bis((2,6-diisopropylphenyl)amide-κ2N′′,N′′′)manganese(II), C44H54N4Mn