Dopamine interaction with a polyamine cryptand of 1H-pyrazole in the absence and in the presence of Cu(ii) ions. Crystal structure of [Cu2(H−1L](ClO4)3·2H2O

Abstract

Supramolecular chemistry has developed through the preparation of sophisticated molecular receptors which are able to discriminate and induce characteristic properties in given substrates. 1 Tridimensional cryptand-like receptors with appropriate arrangements of binding sites have yielded interesting patterns in many aspects of molecular recognition like metal ion or anion coordination chemistry. 1,2 We have previously reported the synthesis, basicity and complexing properties of polyamine coronands of 1H-pyrazole able to form Zn 2+ and Cu 2+ pyrazolate salts. 3,4 Herein we report on a polyamine cryptand of related structure. 5 We advance the results of a study on its interaction with Cu 2+ and on the formation of mixed complexes with the biologically relevant neurotransmitter dopamine. 6 Ligand L was prepared as reported in ref. 5 by reacting 3,5-pyrazoledicarbaldehyde and tris(2-aminoethyl)amine in 3+2 molar ratio in MeOH, followed by reaction in situ with NaBH 4 .

CuII and ZnII Coordination Chemistry of Pyrazole‐Containing Polyamine Receptors − Influence of the Hydrocarbon Side Chain Length on the Metal Coordination

“…(2) and L 3 (3) were prepared by treatment of the corresponding 3,5-pyrazoledicarbaldehydes with diethylenetriamine [L 1 (1) and L 3 (3)] or tris(2-aminoethyl)amine L 2 (2) as reported previously in refs. [10,11] , respectively. (3-aminopropyl)-1,3-propanediamine (525 mg, 4 mmol) in dry methanol (120 mL) over 2.5 h. The reaction was monitored by TLC (CHCl 3 / MeOH, 10:1) and when it was complete (ca.…”

Cu2+-Induced formation of cage-like compounds containing pyrazole macrocycles

“…[4][5][6] The first of these receptors L 1 takes up, both in solution and in the solid state, two Cu 2+ metal ions. Its X-ray structure revealed a strongly distorted square pyramidal coordination geometry around each copper centre.…”

“…The Cu(1)-Cu(2) distance of 3.967 Å falls within the range found for related complexes. † [4][5][6]8 Scheme 1…”

“…Recently we have reported on the Cu 2+ complex formation of the 1H-pyrazole polyamine coronand L 1 and of the cage ligand L 2 . [4][5][6] The first of these receptors L 1 takes up, both in solution and in the solid state, two Cu 2+ metal ions. Its X-ray structure revealed a strongly distorted square pyramidal coordination geometry around each copper centre.…”

Enantioselective binding of amino acids and amino alcohols by self-assembled chiral basket-shaped receptors

“…13 -20 More recently, a copper complex of a pyrazole-containing cryptand that binds dopamine in water with a high binding constant has been reported. 21,22 Diphenylglycoluril based clip molecules have been prepared and extensively studied in the Nolte group over the past 10 years. These hosts possess a well defined cavity that allows the binding of different phenolic guests via a combination of several non covalent interactions (H-bonding, p-p stacking, and the cavity effect).…”