A binuclear CuII/CaII thio-cyanate complex with a Schiff base ligand derived from o-vanillin and ammonia

The new heterometallic complex, aqua-1κO-bis-(μ2-2-imino-methyl-6-meth-oxy-phenolato-1κ2 O 1,O 6:2κ2 O 1,N)bis-(thio-cyanato-1κN)calcium(II)copper(II), [CaCu(C8H8NO2)2(NCS)2(H2O)], has been synthesized using a one-pot reaction of copper powder, calcium oxide, o-vanillin and ammonium thio-cyanate in methanol under ambient conditions. The Schiff base ligand (C8H9NO2) is generated in situ from the condensation of o-vanillin and ammonia, which is released from the initial NH4SCN. The title compound consists of a discrete binuclear mol-ecule with a {Cu(μ-O)2Ca} core, in which the Cu⋯Ca distance is 3.4275 (6) Å. The coordination geometries of the four-coordinate copper atom in the [CuN2O2] chromophore and the seven-coordinate calcium atom in the [CaO5N2] chromophore can be described as distorted square planar and penta-gonal bipyramidal, respectively. In the crystal, O-H⋯S hydrogen bonds between the coordinating water mol-ecules and thio-cyanate groups form a supra-molecular chain with a zigzag-shaped calcium skeleton.

Compartmentalization of Alkaline-Earth Metals in Salen-Type Cu- and Ni-Complexes in Solution and in the Solid State

The precise arrangement of metal ions in type and number by a ligand represents an important challenge in biology as well as in materials science. The preorganization of different metal ions such as alkaline-earth and transition-metal ions is of particular interest for the design of catalysts or precursors of oxides. This study is based on a Ω-shaped salen-derived ligand comprising N2O2 and O2O2 coordination sites. The selective binding of Cu(II) and Ni(II) and alkaline-earth-metal ions is influenced by many factors such as the size of the cation, the solvent, or the counterion. UV-vis and 1H NMR titrations and single-crystal X-ray structures reveal that the obtained complexes tend to adopt different structures in solution compared to the solid state. Mainly discrete motifs with a stoichiometry 1:1 (LM1 to alkaline-earth-metal ions) have been shown to form in the solid state, whereas in solution, the 2:1 complexes are predominant.

Non-covalent tetrel bonding interactions in hemidirectional lead(ii) complexes with nickel(ii)-salen type metalloligands

Tetrel bonding interactions have been investigated in hetero-dinuclear nickel(ii)/lead(ii) complexes using MEP and DFT calculations.

On the importance of Pb⋯X (X = O, N, S, Br) tetrel bonding interactions in a series of tetra- and hexa-coordinated Pb(ii) compounds

We study Pb⋯X (X = N, S, Br) tetrel bonding interactions in a series of tetra- and hexa-coordinated Pb(ii) compounds that exhibit hemidirectional coordination.

Formation of a water-mediated assembly of two neutral copper(ii) Schiff base fragments with a Cu2(NCS)4moiety: exploration of non-covalent C–H⋯π(bimetallo ring) interactions

The energetic features of dimer formation and water encapsulation in an interesting copper(ii) Schiff base complex, [(CuL)₂⊂(H₂O)][Cu₂(μ_1,3-NCS)₂(NCS)₂], have been studied using DFT calculations.

A double decker type complex: copper(i) iodide complexation with mixed donor macrocycles via [1 : 1] and [2 : 2] cyclisations

19-membered and a 38-membered macrocycles obtained as a mixture via respective [1 : 1] and [2 : 2] cyclisations were separated and their coordination behaviours with copper(i) iodide were investigated. One of the notable products isolated is a tetranuclear bis(macrocycle) complex with the larger macrocycle adopting a double decker type structure. Furthermore, removal of the lattice solvent molecules in the above complex in air motivates the displacement of the double decker units along the a-axis by sliding in a single-crystal-to-single-crystal manner.