Unprecedented copper(ii)-assisted acetal formation of a formyl-substituted bispyrazole. The X-ray structures of copper[1,2-bis(3′-dimethoxymethylpyrazol-1′-yl)ethane] dichloride and dibromide

Abstract

The formation of two new acetal-containing ligands 1,2-bis(3Ј-dimethoxymethylpyrazol-1Ј-yl)ethane (bdmpe) and 1,2-bis(3Ј-diethoxymethylpyrazol-1Ј-yl)ethane (bdepe) in a Cu()-assisted alcoholysis of the initial ligand 1,2-bis(3Ј-formylpyrazol-1Ј-yl)ethane is described. The new ligands form polymeric complexes with Cu() salts of the general formula [Cu(L)X 2 ] x , where L = bdmpe or bdepe, and X = Cl or Br. The single-crystal X-ray structures of [Cu(bdmpe)Cl 2 ] x and [Cu(bdmpe)Br 2 ] x show that two of the four oxygen atoms of the acetal fragments are axially semi-coordinated to the copper() ions, adjusting the coordination sphere around the metal ion to a very distorted octahedron. The coordination of the oxygen atoms of the acetal groups to the metal ion may well be the driving force for the transformation of the initial aldehyde groups into the acetal fragments. The equatorial plane in [Cu(bdmpe)Cl 2 ] x is a trans-CuN 2 Cl 2 chromophore, while in [Cu(bdmpe)Br 2 ] x it is a cis-CuN 2 Br 2 species with a large in-plane distortion.

Ligand design in coordination chemistry: approaches to new catalysts, new materials, and a more sustainable environment

“…cases are the so-called Schiff-base couplings; 4 in other cases rather unique ligands can be formed only when the metal is present. 5,6 Although ligand design nowadays plays a major role in almost all sub-areas of coordination chemistry, we have decided to concentrate in the present Dalton Discussion conference (DD5) and this Dalton Transactions issue on 4 major themes, each of which will be detailed below. Of course one could think of many other areas where ligand design is extremely important, such as in Analytical Chemistry, and in Medicinal Chemistry, where the ligands such as those for Pt, Ru and Au determine the therapeutic or diagnostic properties of the coordination complexes.…”

“…More recently, Reinaud et al, 118 incorporated imidazole ligands onto a tert-butylcalix [6]arene, such that the resulting zinc complex contained solvent molecules coordinated to the zinc within the hydrophobic cavity of the calixarene (Fig. 18).…”

A Nanoporous Supramolecular Metal–Organic Framework Based on a Nucleotide: Interplay of the π···π Interactions Directing Assembly and Geometric Matching of Aromatic Tails

“…Within the framework of our works on the use of enantiopure nucleosides- [ 51 , 70 , 71 , 72 ] or nucleotides-based metal complexes [ 52 , 73 ] to generate supramolecular architectures of different dimensionality, we report here on the self-assembly of cytidine 5’-monophosphate (CMP) biomolecule and copper metal ions for the preparation of a unique supramolecular metal-organic framework with the formula [Cu 6 (bipy) 6 (CMP) 2 (µ-O)Br 4 ]·Br 2 ·46H 2 O ( CMP-MOF 1 ).…”