N-HO and N-HCl supported 1D chains of heterobimetallic Cu/Ni-Sn cocrystals.

The Schiff base HL [N,N'-ethylenebis(3-methoxysalicylaldimine)] or HL [N,N'-ethylenebis(3-ethoxysalicylaldimine)] was reacted with MCl·xHO and SnCl·5HO to afford the supramolecular heterobimetallic systems (HED)·2[ML]·[SnCl] [M = Cu, L = L (1), L = L (2); M = Ni, L = L (3), L = L (4); ED = 1,2-ethylenediamine], whose structures were established by single crystal X-ray analyses. Each structure includes different entities, viz. a mononuclear [CuL]/[NiL] neutral complex (coformer), a hexachlorostannate dianion [SnCl], a 1,2-ethylenediammonium dication (HED) and, only in 2 and 4, a methanol molecule. Based on the work of Grothe et al. (Cryst. Growth Des., 2016, 16, 3237-3243), compounds 1 and 3 are cocrystal salts, 2 and 4 are cocrystal salt solvates. The ionic pairs (HED)·[SnCl] in 1-4 are encapsulated by the Cu- or Ni-complexes, and stabilized by N-HO and one N-HCl bond interactions leading to infinite 1D chains. The antimicrobial studies of 1-4 against yeasts (C. albicans and S. cerevisiae) and Gram-positive (S. aureus and E. faecalis) and -negative bacteria (P. aeruginosa and E. coli) indicate that the NiSn systems (3 and 4) are more active than the analogous CuSn ones (1 and 2).