Isolation of Two Different Ni₂Zn Complexes with an Unprecedented Cocrystal Formed by One of Them and a “Coordination Positional Isomer” of the Other

Abstract

A new homometallic trinuclear Ni(II) complex [(NiL)2Ni(NCS)2] (1) and three heterometallic trinuclear Ni(II)-Zn(II)-Ni(II) complexes [(NiL)2Zn(NCS)2] (2), [(NiL)2Zn(NCS)2(CH3OH)2]·2CH3OH (3) and {[(NiL)2Zn(NCS)2(CH3OH)2]} {[(NiL)2Zn(NCS)2]} (4) have been synthesized by using the "complex as ligand" approach with the "metalloligand" [NiL] (H2L = N,N'-bis(salicylidene)-1,3-propanediamine) and thiocyanate in different ratios. All the complexes have been structurally and magnetically characterized. In the isomorphous complexes 1 and 2, the two terminal square planar Ni atoms and the central octahedral nickel atom (in 1) or zinc atom (in 2) are arranged in a bent structure where two cis κN-SCN(-) thiocyanate ions are coordinated to the central atom. The chemical composition of 3 is very similar to that of 2 but, in 3, the central Zn atom is tetrahedral and the κN-SCN(-) thiocyanate ions occupy an axial position of each terminal nickel atom (which now are octahedral with the sixth position occupied by a methanol molecule). Complex 4 consists of two closely related trinuclear units 4A and 4B. In 4A, the coordination environments of the metals are identical to those of 3 whereas 4B is a "coordination position isomer" of complex 2 with the central square pyramidal Zn and one of the terminal square pyramidal Ni atoms coordinated by two κN-SCN(-) thiocyanate ions. Complex 4 is a unique example of a cocrystal formed by two similar trinuclear units (4A and 4B) where 4A is identical to an existing complex (3) and 4B is a "coordination position isomer" of another existing complex (2).

An investigation of structure, Hirshfeld surface, and fluorescence properties of two dinuclear Ni (II) and Zn (II) salamo‐type complexes

“…Complex 2 crystallizes in the C 2 /c space group of the monoclinic system, and the crystal structure indicated that complex 2 contains three discrete neutral dinuclear 2 A, 2 B and 2 C units (Figure 6a), [ 1,2 ] at the same time, three crystallized CHCl 3 and one CH 3 OH. Each unit contains one completely deprotonated ligand (L) 3− , two Zn (II) ions in N 2 O 3 coordination environment, one μ ‐OMe − anion.…”

“…In summary, two novel dinuclear Ni (II) and Zn (II) salamo-type complexes [Ni 2 L(MeOH)(μ-OAc)]Á 2CHCl 3 (1) and [{Zn 2 L(μ-MeO)} 3 ]Á3CHCl 3 ÁCH 3 OH (2), have been successfully synthesized by wet-chemical method. Complex 1 consists of two closely related dinuclear 1A and 1B units, and complex 2 consists of three closely related dinuclear 2A, 2B and 2C units, which are unique example of complexes formed by crystallographically independent but chemically identical molecules.…”

“…Complex 1 crystallizes in the P 2 1 /n space group of the monoclinic system, and the crystal structure indicated that complex 1 contains two discrete neutral dinuclear units 1A and 1B (Figure 3a). [1,2] Each unit contains one completely deprotonated (L) 3À , two Ni (II) atoms in N 2 O 4 coordination environments, one coordinated methanol molecule, one μ-OAc À counter anion, as well as two crystallized CHCl 3 . The Ni (II) atom (Ni1) of 1A molecule is in a hexa-coordinated N 2 O 4 coordination environment, and four of the equatorial sites about the Ni1 center are occupied by the donor atoms (N1, N3, O1 and O6) of the ligand (L) 3À unit, while the remaining available axial areas are occupied by O14 atom of the methanol molecule and O13 atom of μ-OAc À counteranion, respectively, finally, the distorted octahedron geometry around the Ni1 is formed (Figure 3b).…”

“…), which are allowed for during refinement, this disordered orientation is similar to that for previously reported. [5] 3.3.2 | The crystal structure and supramolecular interactions of complex 2 Complex 2 crystallizes in the C 2/c space group of the monoclinic system, and the crystal structure indicated that complex 2 contains three discrete neutral dinuclear 2A, 2B and 2C units (Figure 6a), [1,2] at the same time, three crystallized CHCl 3 and one CH 3 OH. Each unit contains one completely deprotonated ligand (L) 3À , two Zn (II) ions in N 2 O 3 coordination environment, one μ-OMe À anion.…”

“…As an important part of chemistry, coordination chemistry has always been active in various fields therein. [1][2][3][4][5][6][7][8][9][10] In salen-based ligands and their corresponding complexes, due to their potential application values, for several decades, the research heat is still great in modern coordination chemistry. Therefore, the construction of novel and functional metal complexes has become a research hotspot of salen-based ligands, with the further study of N 2 O 2 -donor ligands and their corresponding complexes, which has widely used in the fields of magnetism, [11][12][13] fluorescent materials [14][15][16][17][18] and catalysis.…”