Investigation on structurally different Cu(II) and Ni(II) complexes constructed from a novel pyridine-terminal salamo-like ligand.

The Cu(II) and Ni(II) complexes self-assembled from a novel salamo-like ligand H 2 L containing double terminal pyridine groups, [Cu(LH)]NO 3 ⋅CH 3 CH 2 OH and [{Ni(L)} 2 ] n ·nC 5 H 5 N⋅nCH 3 COCH 3 were designed and synthesized. The Cu(II) atom is located at the N 2 O 2 cavity of the deprotonation ligand (L)2− moiety, but the N atoms of the terminal pyridine groups of the ligand (L)2− moiety is not involved in the coordination, and forms a four-coordinated twisted quadrilateral geometry. While the Ni(II) atom (Ni1 or Ni2) is sited in the N 2 O 2 cavity of the deprotonation ligand (L)2− moiety and forms a plane, the terminal pyridine N atoms from the two adjacent [Ni(L)] moieties also coordinated with the Ni(II) atom in the axial positions to form a slightly distorted octahedral geometry with six-coordination. The benzene and pyridine rings of the ligand (L)2− moiety are rotated and create an angle, result to form a chiral MOFs using an achiral ligand (L)2− moiety. • Containing double terminal pyridine groups novel salamo-like ligand was synthesized. • The structurally different Cu(II) and Ni(II) complexes were self-assembled. • The Cu(II) and Ni(II) complexes have huge structural differences. • Compared with the Cu(Ⅱ) complex, the Ni(Ⅱ) complex has better thermal stability. A novel structurally characterized salamo-like ligand H 2 L contained double terminal pyridine groups was designed and synthesized. The single crystals of the Cu(II) and Ni(II) complexes are grown up through coordination of H 2 L with Cu(II) and Ni(II) ions, respectively, determined as [Cu(LH)]NO 3 ⋅CH 3 CH 2 OH and [{Ni(L)} 2 ] n ·n3C 5 H 5 N·nCH 3 COCH 3. The Cu(II) atom is located at the N 2 O 2 cavity of the deprotonation ligand (L)2− moiety, but the N atoms of the terminal pyridine groups of the ligand (L)2− moiety is not involved in the coordination, and forms a four-coordinated twisted quadrilateral geometry. While the Ni(II) atom (Ni1 or Ni2) is sited in the N 2 O 2 cavity of the deprotonation ligand (L)2− moiety and forms a plane, the terminal pyridine N atoms from the two adjacent [Ni(L)] moieties also coordinated with the Ni(II) atom in the axial positions to form a slightly distorted octahedral geometry with six-coordination. In the formation of MOFs, the benzene and pyridine rings of the ligand (L)2− moiety are rotated and create an angle, result to form a chiral MOFs using an achiral ligand (L)2− moiety. View of MOFs in the C direction, the Ni(II) complex has four different size of apertures in its structure, and presences a large amount of protonic hydrogen. Spectroscopic analyses of H 2 L and its Cu(II) and Ni(II) complexes are performed using IR, UV–Vis and fluorescence spectroscopy. Compared with the Cu(II) complex, the Ni(II) complex has better thermal stability. The magnetic analyses were also carried out. Hirshfeld surfaces analyses are carried out to analyze various short-range interactions in H 2 L and its Cu(II) complex. [ABSTRACT FROM AUTHOR]