Synthesis and crystal structure study of (<i>R</i>,<i>R</i>)-TMCDA ethanol derivatives doubly protonated with FeCl₄ ⁻ and Cl⁻ as counter-ions

The synthesis and structural characterization of the crystal forms of (<i>R</i>,<i>R</i>)-TMCDA and its ethanol derivative, both doubly protonated with FeCl₄ ^- and Cl^- as counter-ions, are reported, namely, (<i>R</i>,<i>R</i>)-<i>N</i> ¹,<i>N</i> ¹,<i>N</i> ²,<i>N</i> ²-tetra-methyl-cyclo-hexane-1,2-bis-(aminium) tetra-chlorido-ferrate chloride, (C₁₀H₂₄N₂)[FeCl₄]Cl (<b>1a</b>), and (<i>R</i>,<i>R</i>)-<i>N</i> ¹-(2-hy-droxy-eth-yl)-<i>N</i> ¹,<i>N</i> ²,<i>N</i> ²-tri-methyl-cyclo-hexane-1,2-bis-(aminium) tetra-chlorido-ferrate chloride (C₁₁H₂₆N₂O)[FeCl₄]Cl (<b>2a</b>). A notable feature across both synthesized compounds is the presence of N-H⋯Cl hydrogen bonds of moderate strength in the solid state. In the case of the ethanol derivative of (<i>R</i>,<i>R</i>)-TMCDA, the structure also reveals the formation of inter-molecular O-H⋯Cl hydrogen bonds.