Synthesis of a novel dinucleating aminocarboxylate macrocycle and structures of its dinuclear complexes with di- and trivalent transition and lanthanide metal ions

Abstract

The synthesis of the new ligand L1(H4L1= 3,8,16,21-tetrakis(carboxylmethyl)-3,8,16,21,27,28-hexaazatricyclo[21.3.1.1(10,14)]octacosa-1(27),10,12,14(28),23,25-hexaen-5,18-diine) is reported. The solid-state structures of the four homodinuclear chelate complexes, [Zn2(L1)(H2O)2] x 6H2O, [Fe2(L1)(mu-O)] x 4H2O, [La2(L1)(NO3)2(H2O)2] x 6H2O and Na[Eu2(L1)(mu-AcO)3] x 3H2O, were determined by single-crystal X-ray structural analysis.

Macrocyclic coordination chemistry

“…The new macrocyclic ligand 3,8,16,21-tetrakis(carboxylmethyl)-3,8,16,21,27,28-hexaazatricyclo[21.3.1.1 10,14 ]octacosa-1(27),10,12,14(28),23,25-hexaen-5,18-diine, L 34 , was synthesised and bimetallic complexes of zinc(II), iron(III), lanthanum(III) and europium(III) were characterised by X-ray crystallography. 52 The analogue of this macrocycle with an additional pyridyl group at each end of the cavity, L 35 , was synthesised and complexed with copper(II) to produce a small molecule phosphoryl transfer catalyst. 53 The dicopper complex promotes the transesterification of simple inert dialkyl phosphates and the mechanism was investigated using DFT calculations.…”

17 Macrocyclic coordination chemistry

“…Both the monomeric [ML] 2+ and the dimeric [M 2 L] 4+ complexes were studied; the [Co 2 L] 4+ complexes binding oxygen. 2 The structural characterization of four Cd II macrocyclic complexes containing mixed N-, O-and S-donors [Cd(NO 3 ) 2 ([12]aneN 2 S 2 )], [Cd(NO 3 ) 2 ([12]aneNS 3 )], [Cd(NO 3 ) 2 ([15]aneNO 2 S 2 )] and [Cd(NO 3 )( [15]aneN 2 O 2 S)]NO 3 (L [7][8][9][10] ) has been achieved to evaluate the conformational flexibility of aza-thioether macrocycles. 3 The metal ion is coordinated outside of the macrocyclic cavity in the complexes of the smaller macrocycles ( [12]aneN 2 S 2 and [12]aneNS 3 ), whereas the flexibility of the larger macrocycles ( [15]aneN 2 O 2 S) and ( [15]aneNO 2 S 2 ) allow very different conformations to be adopted.…”

“…2 The structural characterization of four Cd II macrocyclic complexes containing mixed N-, O-and S-donors [Cd(NO 3 ) 2 ([12]aneN 2 S 2 )], [Cd(NO 3 ) 2 ([12]aneNS 3 )], [Cd(NO 3 ) 2 ([15]aneNO 2 S 2 )] and [Cd(NO 3 )( [15]aneN 2 O 2 S)]NO 3 (L [7][8][9][10] ) has been achieved to evaluate the conformational flexibility of aza-thioether macrocycles. 3 The metal ion is coordinated outside of the macrocyclic cavity in the complexes of the smaller macrocycles ( [12]aneN 2 S 2 and [12]aneNS 3 ), whereas the flexibility of the larger macrocycles ( [15]aneN 2 O 2 S) and ( [15]aneNO 2 S 2 ) allow very different conformations to be adopted. Two N-methylphosphonic acid derivatives, H 4 L 11 and H 6 L 12 , of a 14-membered tetraazamacrocycle containing pyridine have been synthesized; 4 complexes of these ligands have stability constants similar to or higher than those formed with ligands of the same macrocyclic backbone but with acetate arms.…”

Synthesis, characterization and crystal structures of mono and dinuclear macrocyclic cobalt(ii) complexes with a new tetraaza m-xylyl-based macrocyclic ligand

“…10,11 Such systems show interesting magnetic behaviour (antiferromagnetic or ferromagnetic coupling) and since the biological action of many metalloproteins such as hemocyanin and urease is associated with the occurrence of metal ions in pairs, they can be used as models to understand the reactivity changes caused by the proximity of the two metals, and also to understand the reactivity of metalloenzymes. [10][11][12][13][14][15][16][17][18][19][20] We have previously reported the complexation of copper(I) ions by the 20-membered macrocyclic Schiff base ligand (PL, Scheme 1). 11,21 Herein, we report the synthesis, properties and structural characterization of a series of mono-and di-cobalt(II) complexes of a macrocyclic ligand having a 20-membered inner large ring with N4 donors and containing different halogen counter ions.…”