Novel isomorphism of two hexagonal non-centrosymmetric hybrid crystals of M(en)3Ag2I4 (M = transition metal Mn2+ or main-group metal Mg2+; en = ethylenediamine)

Abstract

In this study, two isomorphic hybrid crystals of iodoargentate, M(en)₃Ag₂I₄ (M = transition metal Mn²⁺ (1) or main-group metal Mg²⁺ (2) ion), have been prepared through in situ self-assembly in DMF solution at ambient temperature and characterized by microanalysis, IR spectroscopy, thermogravimetric analysis and powder X-ray diffraction and single crystal X-ray diffraction techniques. The magnetic properties of 1 have been investigated. The crystals of 1 and 2 crystallize in the hexagonal non-centrosymmetric space group P6₃22 with rather similar lattice parameters. The metal complex M(en)₃²⁺ (M = Mn²⁺ or Mg²⁺) with the symmetry of D₃ point group plays a crucial role in directing the formation of the three-dimensional hexagonal non-centrosymmetric framework of {Ag₂I₄²⁻}_∞. To the best of our knowledge, the hybrid Mg(en)₃Ag₂I₄ is the first example of a main-group metal complex used as a structure directing agent for the formation of a hybrid crystal structure, and this is also the first instance where isomorphic hybrid crystals are obtained using transition and main-group metal complexes. These findings can provide a basis for broadening the utilization of metal coordination cations/anions as structure directing agents in the design and construction of novel hybrid crystal structures in more effective ways.