Synthesis, structure and magnetic properties of Ni(II) and Cu(II), [2 × 2] grid complexes of pyrimidine-based symmetric ditopic ligands.

Graphical abstract Three new tetranuclear square Cu(II) and Ni(II), [2 × 2] grid complexes comprising Symmetrical ditopic open chain ligands with terminal carboxylate/oxime functions and central pyrimidine ring are reported. These [2 × 2] square grids are dominated by intramolecular antiferromagnetic exchange coupling. Highlights • Synthesis of symmetrical ditopic open chain ligands with terminal carboxylate/oxime functions and central pyrimidine ring are reported. • Three new tetranuclear square Cu(II) and Ni(II), [2 × 2] grid complexes have been isolated and structurally characterized. • Reported complexes show dominantly intramolecular antiferromagnetic exchange coupling. • The reported ligands demonstrate the propensity for expanded cluster growth, if the right combination of donor components and reaction conditions are chosen. Abstract The successful synthesis of new pyrimidine based organic ligands with terminal carboxylate and oxime functional groups, followed by their employment in metallogrid self-assembly has yielded three tetranuclear [Ni 4 (L1) 4 ]∙2CH 3 CN∙4CH 3 OH·4H 2 O (1), [Cu 4 (HL1′) 4 ]∙8CH 3 OH·28H 2 O (2) and [Ni 4 (H 2 L2) 4 ](CF 3 SO 3) 8 ∙4CH 3 NO 2 ·8H 2 O (3), [2 × 2] metallogrid complexes. The complexes have been well characterized by elemental analyses, IR spectra, UV-vis spectra and X-ray structural analyses. Variable temperature magnetic measurements/studies done on these three complexes followed by magnetic data fitting suggest that all the three complexes are dominated by intramolecular antiferromagnetic exchange coupling. [ABSTRACT FROM AUTHOR]