Diaqua­[methyl 4-O-benzyl-2,3,6-tri-O-(2-picol­yl)-α-D-mannopyran­oside]­cobalt(II) bis­(perchlorate) monohydrate: partial coordination of a ligand derived from D-mannose

The title compound, [Co(C₃₂H₃₅N₃O₆)(H₂O)₂](ClO₄)₂·H₂O, contains a cationic complex with a novel facultative hexa­dentate sugar-derived ligand coordinated in a tetra­dentate fashion to give a CoN₂O₄ coordination. The partial coordination is imposed by the rigid conformation of the sugar. The pyridine group that is not bound to the metal is free to participate in inter­molecular hydrogen bonding and π–π stacking inter­actions.

2,2-Dimethyl-5-nitroso-1,3-dioxan-5-yl benzoate, 2,2-dimethyl-5-nitroso-1,3-dioxan-5-yl 4-chloro­benzoate and 5-nitroso-1,3-dioxan-5-yl 4-chloro­benzoate

The crystal structures of 2,2-dimethyl-5-nitroso-1,3-dioxan-5-­yl benzoate, C₁₃H₁₅NO₅, (I), 2,2-dimethyl-5-nitroso-1,3-dioxan-5-yl 4-chloro­benzoate, C₁₃H₁₄ClNO₅, (II), and 5-nitroso-1,3-dioxan-5-yl 4-chloro­benzoate, C₁₁H₁₁NO₅, (III), have been determined in order to gain insight into the conformational preference of α-benzoyl­oxy­nitroso. Unfavourable 1,3-diaxial inter­actions force (I) and (II) to crystallize in the 2,5 twist-boat conformation, whereas compound (III), lacking this destabilizing inter­action, crystallizes in the chair conformation.