3,5-Lutidine coordinated zinc(II) aryl carboxylate complexes: Precursors for zinc(II) oxide

Abstract The reaction of Zn( κ 2 O,O′–OAc) 2 ·2H 2 O with two equiv of 3,5-lutidine in methanol at room temperature for 12 h afforded [Zn(OAc) 2 (3,5-lutidine) 2 ]· H 2 O ( 1 ) in 91% yield. The acetate exchange reaction of 1 with two equiv of aryl carboxylic acids in methanol at room temperature for 12 h afforded [Zn( μ 2 - κ 1 O: κ 1 O′–O 2 CAr) 2 (3,5-lutidine)] 2 [Ar = C 6 H 5 ( 2 ) and C 6 H 4 Me-3 ( 3 )], [Zn(OC(O)C 6 H 4 Me-2) 2 (3,5-lutidine) 2 ] ( 4 ) and [Zn( κ 2 O,O′−O 2 CC 6 H 4 Me-4) 2 (3,5-lutidine) 2 ] ( 5 ) in ⩾90% yield. Complexes 1 – 5 were characterized by microanalytical, IR, solution ( 1 H and 13 C) and solid-state cross-polarization magic angle spinning 13 C NMR and X-ray diffraction data. The zinc atom in 1 is surrounded by nitrogen atom of two 3,5-lutidine and oxygen atom of two monodentate acetate moiety and thus attains a tetrahedral geometry. One of the acetate moieties is hydrogen bonded with a water molecule in the crystal lattice. Complexes 2 and 3 possess a dinuclear paddlewheel framework with a square pyramidal geometry around the zinc atom whereas 4 and 5 are mononuclear species with the zinc atom in tetrahedral and an octahedral geometry, respectively. Thermogravimetric analyses of 2 – 5 suggested ZnO as the decomposed product followed by the confirmation from the powder X-ray diffraction patterns. Enormous gas evolution resulting in porous ZnO during thermal decomposition was evidenced from scanning electron microscopic images.