Organically Directed Iron Sulfate Chains: Structural Diversity Based on Hydrogen Bonding Interactions

Six organically directed 1-D iron sulfates hydrated and hydrolyzed to different extents have been prepared
hydrothermally. [C2H10N2]1.5[Fe(SO4)3]·2H2O (I), [C2H10N2][Fe(SO4)2(OH)]·H2O (II), [C6H18N2]0.5[Fe(SO4)2(H2O)2] (III),
and [C6H18N2]0.5[Fe2(SO4)(H2O)4(OH)]·H2O (V) possess the linear topological structures observed in ferrinatrite,
sideronatrite, kröhnkite, and copiapite minerals, respectively. [C4H12N2][Fe2(SO4)3(OH)2(H2O)2]·H2O (IV) shows a
novel linear structure that can be regarded as a hybrid of the tancoite and butlerite types. [C6N4H22]0.5[Fe(SO4)2(OH)]·2H2O (VI) adopts a cis configuration, compared with II, to give a rare inorganic helical iron sulfate chain
which is a new member of the organically directed transitional metal sulfates. The results reveal that the starting
molar proportion of the reactants and the type of amines are critical for the structural motif. There is an obvious
relationship between the constitution of chains and the type of amino groups, involving the amount of N−H···O
hydrogen bonds.