[ N , N ′-Bis(2,6-diisopropylphenyl)pentane-2,4-diamine(1–)-2κ 2N , N ′]-μ 2 -chlorido-1:2κ 2Cl : Cl -chlorido-2κ Cl -bis(1,2-dimethoxyethane-1κ 2O , O ′)iron(II)lithium