Polynuclear Complexes with Alkoxo and Phenoxo Bridges from In Situ Generated Hydroxy-Rich Schiff Base Ligands: Syntheses, Structures, and Magnetic Properties

Complexes of new Schiff base ligands generated in situ from the reaction of 1-aminoglycerol, aldehydes, and metal ions are reported. [Cu-4(HL1)(4)] (1) and [Ni4O(HL1)(3)(H2O)(3))]6H(2)ODMFDMSO (2) have M4O4 cubane cores, with the L/M molar ratios of 4:4 and 3:4, respectively. [(Mn3MnNaOCl4)-Mn-III-Na-II(HL1)(3)]3MeCN (3) has a unique pentanuclear trigonal propeller-shaped (Mn3MnNa)-Mn-III-Na-II core structure, and the coordination assemblies are linked by hydrogen bonds to afford a 3D channel structure. [Cu-2(HL2)(2)] (4) has a bis((2)-alkoxo)-bridged Cu2O2 core, with the binuclear species linked by hydrogen bonds to afford a 1D double-chain. [Ni-7(OH)(2)(OCH3)(4)(H2L3)(2)(MeOH)(2)(H2O)(2)]- (ClO4)(2)10H(2)O (5) has a heptanuclear structure containing heptadentate di-Schiff base ligands, with the nickel(II) ions bridged by phenoxo, alkoxo, hydroxo, and methoxo groups to afford a very rare face-sharing hexadruple defective cubane core with a Ni@Ni-6 arrangement. The lattice water molecules are linked by hydrogen bonds to form helical chains, which are further hydrogen-bonded to the coordination moieties to afford a 2D network. Variable temperature magnetic susceptibility measurements and nonlinear data-fitting revealed that the 2+4 type of cubane complex 1 shows medium intradimeric ferromagnetic interactions and weak interdimeric ferromagnetic interactions. For complexes 2 and 5, coexistent ferro- and antiferromagnetic couplings afford a non-zero spin ground state. However, compound 3 shows antiferromagnetic interactions between Mn-III and Mn-II, and ferromagnetic interactions between the Mn-III centers, resulting in a global antiferromagnetic behavior. In conclusion, the reaction of 1-aminoglycerol with aldehydes and metal salts afforded polynuclear complexes with a rich structural diversity and remarkable magnetic behavior.