Syntheses, crystal structures and supramolecular topologies of nickel(II)–s/p/d10/NH4+ complexes derived from a compartmental ligand

Abstract

The syntheses, characterization and crystal structures of ten complexes of composition [{NiIILLiI(H2O)2}{NiIIL}2](ClO4) (1), [NiIILNaI(ClO4)(CH3OH)] (2), [(NiIIL)2NaI](BPh4)·CH3COCH3 (3), [(NiIIL)2RbI](BPh4)·CH3COCH3 (4), [(NiIIL)2CsI](ClO4)·CH3CN (5), [{NiIILMgII(H2O)3}{NiIIL}2](ClO4)2 (6), [NiIILCaII(NO3)2(H2O)]·1.5H2O (7), [NiIILCdII(NO3)2]·CH3CN (8), [NiIILPbII(NO3)2] (9) and [(NiIIL)2(NH4)](PF6) (10) are reported, where H2L = N,N′-ethylenebis(3-ethoxysalicylaldimine). The crystal systems and space groups are: triclinic Pī for 1, 4, 5 and 8, monoclinic P21/c for 2, 3, 7 and 9, monoclinic C2/c for 6 and monoclinic P21/n for 10. In 1–10, the salen type N2O2 compartment of [L]2− is occupied by a NiII ion, while the larger and open O(phenoxo)2O(ethoxy)2 compartment interacts with LiI in 1, NaI in 2 and 3, RbI in 4, CsI in 5, MgII in 6, CaII in 7, CdII in 8, PbII in 9 and NH4+ in 10. Compounds 1 and 6 are [2 × 1 + 1 × 2] tetrametallic cocrystals of one diphenoxo-bridged dinuclear NiIILiI (for 1) and NiIIMgII (for 6) unit and two mononuclear [NiIIL] moieties. Compounds 2, 7, 8 and 9 are diphenoxo-bridged dinuclear NiIINaI, NiIICaII and NiIICdII and NiIIPbII systems, respectively. On the other hand, compounds 3, 4 and 5 are trinuclear NiII2NaI, NiII2RbI and NiII2CsI systems, respectively, in which each of the two adjacent pairs of metal ions is diphenoxo-bridged. The rubidium(I) and cesium(I) analogues are also double-decker sandwich systems. The ammonium ion in [(NiIIL)2(NH4)](PF6) (10) is sandwiched in between two [NiIIL] moieties due to hydrogen bonds between ammonium hydrogen atoms and O4 compartments. Weak interaction assisted following self-assemblies are observed: dimeric in 1 and one-dimensional in 10 due to Ni⋯Ni weak interaction; one-dimensional in 2 due to C–H⋯π and O–H⋯O hydrogen bonds; nice cyclic topology in 5 due to Ni⋯Ni interaction and C–H⋯O hydrogen bonds; one-dimensional in 6 due to Ni⋯Ni interaction and C–H⋯O hydrogen bond; one-dimensional in 8 due to π···π stacking.