Enantiomorphic Helical Coordination Polymers of {[M(pyrimidine)(OH₂)₄][SiF₆]·H₂O}_∞ (M = Co²⁺, Cu²⁺, Zn²⁺)

Helical coordination complexes, {[M(pyrimidine)(OH₂)₄][SiF₆]·H₂O}_∞; (M = Co, 1; Cu, 2; Zn, 3), were inadvertently but reproducibly isolated when corresponding metal tetrafluoroborates were reacted with pyrimidine in glass vials in 1:1 molar ratios. The crystal structures of complexes 1−3 revealed spontaneously resolved helical coordination polymers in enantiomorphic space groups P4₃2₁2 (1) and P4₁2₁2 (2 and 3) despite the high molecular symmetry associated with the constituent building blocks. The individual helical polymer chains were linked together by hydrogen bonding involving the H₂O solvent and SiF₆^2- anions to form a topologically complex three-dimensional network.