Synthesis, structure and oxygen reduction reaction activity of a Ni-containing tartratoborate Na[Ni(py)2]2·[(C4H2O6)2B]·H2O (py = pyridine) and a copper complex borate [Cu(H2O)2(1-EI)4]·[B5O6(OH)4]2·H2O (1-EI = 1-ethylimidazole)

Two new metal hybrid borates , Na[Ni(py) 2 ] 2 ·[(C 4 H 2 O 6 ) 2 B]·H 2 O (py = pyridine) ( 1 ) and [Cu(H 2 O) 2 (1-EI) 4 ]·[B 5 O 6 (OH) 4 ] 2 ·H 2 O (1-EI = 1-ethylimidazole) ( 2 ), have been successfully synthesized. 1 features an interesting structure based on mixed borate-tartrate motifs. Two tartrate anions are condensed with one BO 4 to form the hybrid anionic group [(C 4 H 2 O 6 ) 2 B] 5− . The structure of 2 is composed of [B 5 O 6 (OH) 4 ] − clusters and [Cu(H 2 O) 2 (1-EI) 4 ] 2+ complexes, which exhibits hydrogen-bonded network formed by [B 5 O 6 (OH) 4 ] − clusters. These compounds are further confirmed by FTIR, PXRD and UV–vis. In addition, the catalyst prepared from 2 shows excellent electrocatalytic oxygen reduction reaction (ORR) activity.