Resolution of a Racemic Small Molecular Alcohol by a Chiral Metal−Organic Coordination Polymer through Intercalation

The resolution of racemic 2-butanol through intercalation by a chiral metal−organic coordination polymer [Cu(PPh₃)(N,N‘-(2-pyridyl-(4-pyridyl methyl)-amine))_1.5]·ClO₄ (1) constructed by an achiral building block provides new insight into the optical-resolution field. This provides encouragement for the role of crystal engineering in separating racemic mixtures and revives the historic practice of mechanically separating crystals of opposite chirality. Crystal data for 1:  C₆₉H₆₃Cl₂Cu₂N₉O₈P₂, trigonal, R3, a = 13.7382(2), b = 13.7382(2), c = 32.72480(10) Å, α = β = 90°, γ = 120°, V = 5348.78(11) ų, Z = 3, M = 1406.20, D_c = 1.310 Mg m^-3, R₁ = 0.0703, wR₂ = 0.1457, S = 0.928, T = 293 K, μ = 0.774 mm^-1; crystal data for 1·1.5 (S)-2-butanol (2):  C₇₅H₇₈Cl₂Cu₂N₉O_9.5P₂, trigonal, R3, a = 13.7282(4), b = 13.7282(4), c = 32.7155(12) Å, α = β = 90°, γ = 120°, V = 5339.6(11) ų, Z = 3, M = 1517.36, D_c = 1.416 Mg m^-3, R₁ = 0.0454, wR₂ = 0.0605, S = 1.019, T = 293 K, μ = 0.783 mm^-1.