Self-assembly of metal(II) tetraaza macrocyclic complexes with cyclobutane-1-carboxylic acid-1-carboxylate ligand linked by hydrogen bond

Abstract

The reaction of [M(L)]Cl 2 Á 2H 2 O (M = Ni 2+ and Cu 2+ , L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4, 0 1.18 ,0 7.12 ]docosane) with 1,1-cyclobutanedicarboxylic acid (H 2 -cbdc) generates 1D and 2D hydrogen-bonded infinite chains [Ni(L)(H-cbdc -) 2 ] (1) and [Cu(L)(H-cbdc -) 2 ] (2).(H-cbdc -= cyclobutane-1-carboxylic acid-1-carboxylate). These complexes have been characterized by X-ray crystallography, spectroscopy, and cyclic voltammetry. The crystal structure of 1 shows a distorted octahedral coordination geometry around the nickel(II) ion, with four secondary amines and two oxygen atoms of the H-cbdc -ligand at the trans position. In 2, the coordination environment around the central copper(II) ion shows a Jahn-Teller distorted octahedron with four Cu-N bonds and two long Cu-O distances. The cyclic voltammogram of the complexes undergoes two oneelectron waves corresponding to M II /M III and M II /M I processes. The electronic spectra and electrochemical behavior of the complexes are significantly affected by the nature of the axial H-cbdc -ligand.

One-Dimensional Hydrogen-Bonded Infinite Chain from Nickel(II) Tetraaza Macrocyclic Complex and 1,2-Cyclopentanedicarboxylate Ligand

“…This interaction gives rise to a 1D hydrogen-bonded infinite chain, which is similar to that observed for the cyclo-aliphatic nickel(II) complexes [Ni(hatt)(H-chdc – ) 2 ] [19] and [Ni(L)(H-cbdc – ) 2 ] [20]. This fact may be due to the flexibility of the trans -1,2-cyclopentanedicarboxylate (H-cpdc – ) ligand as well as trans -1,2-cyclohexanedicarboxylate (H-chdc – ) and1,1-cyclobutanedicarboxylate (H-cbdc – ) ligands.…”

“…The nickel(II) ion exhibits a distorted octahedral coordination geometry with the four secondary amine nitrogen atoms of the macrocycle and two oxygen atoms of H-cpdc – ligands in axial positions. The average Ni-N distance of 2.063(4) Å is significantly longer than in the square-planar geometry of [Ni(L)]Cl 2 ·2H 2 O [1.948(4) Å] [ 22 ], but is similar to those observed for high-spin octahedral nickel (II) complexes with 14-membered macrocyclic ligands [ 15 – 20 ]. The Ni-O distance of 2.176(4) Å is similar to those previously reported values in closely related examples {[Ni(L)] 3 [μ-btc] 2 ·8H 2 O} n (btc 3− = 1,3,5-benzenetricarboxylate, 2.193(4) and 2.163(4) Å) [ 15 ], {[Ni(L)(H-chtc)]·H 2 O} n (chtc 3− = 1,3,5-cyclohexanetricarboxylate, 2.176(6) and 2.152(6) Å) [ 16 ], in which these complexes are 2D coordination and hydrogen-bonded infinite chains.…”

“…Especially, hydrogen bonding is one of the key interactions for the process of molecular aggregation and recognition in nature, which creates novel structures of molecular assemblies [ 14 ]. In particular, self-assembly of macrocyclic complexes containing the square-planar geometry with aromatic and aliphatic polycarboxylate ligands has been proved to be good building blocks for the construction of coordination polymers and metallosupramolecules [ 15 – 20 ]. For example, 1D nickel(II) complexes {[Ni(L)(tp)]·2H 2 O} n ( L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0 1.18 ,0 7.12 ]docosane; tp = terephthalate) [ 15 ] and {[Ni(L)(isotp)]·3H 2 O} n (isotp = isophthalate) [ 16 ] show distorted octahedral geometries and reveal weak antiferromagnetic interactions, which are assembled by square-planar nickel(II) complex [Ni(L)]Cl 2 ·2H 2 O and aromatic dicarboxylate ligands.…”

“…In addition, the octahedral nickel(II) complexes {[Ni(L)(oxalato)]·H 2 O} n [ 17 ] and [Ni(L)(malonato)] n [ 18 ] show that the nickel(II) ions in the complexes are bridged by the aliphatic dicarboxylate ligands to form 1D coordination polymers. However, the cyclo-aliphatic nickel(II) complexes [Ni(hatt)(H-chdc – ) 2 ] (hatt = 1,3,10,12,16,19-hexaazatetracyclo[17,3,1,1 12.16 ,0 4.9 ]tetracosane; H 2 -chdc = trans -1,2-cyclohexanedicarboxylic acid) [ 19 ] and [Ni(L)(H-cbdc – ) 2 ] (H 2 -cbdc = 1,1-cyclobutanedicarboxylic acid) [ 20 ] show the distorted octahedral geometries, which assemble in the solid state to form 1D hydrogen polymers. Therefore, the hydrogen-bonding interactions play a significant role in aligning the molecules and polymer stands in the crystalline solids.…”

Interplay of thermochemistry and Structural Chemistry, the journal (volume 19, 2008) and the discipline

“…In the following paper, Choi and Kim [252] reported the synthesis and characterization of [Ni(L)(H-cdbc -) 2 ] and [Cu(L)(H-cdbc -) 2 ], where L is 3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0 1.18 ,0 7.12 ]docosane and H-cdbc -is cyclobutane-1-carboxylic acid-1-carboxylate. They characterized these complexes using X-ray crystallography, spectroscopy, and cyclic voltammetry.…”