Tuning the Properties of Neutral Tetraazamacrocyclic Complexes of Copper(II) and Nickel(II) for Use as Host–Guest Compounds with Bismacrocyclic Transition Metal Cations

Abstract

The synthesis and structural properties of tetraazamacrocyclic ligands and their neutral and protonated 14-, 15-and 16-membered complexes of Cu II and Ni II are described. Molecules of the free 14-membered ligands have a nonplanar, step-like structure of the central molecular fragments. Conformational changes are introduced upon protonation, with the protons pointing above and below the macrocycle plane. This prevents the formation of intramolecular N-H···N hydrogen bonds. On insertion of the transition metal ions a planar structure of the macrocycle is obtained, which has consequences for the electrochemical behaviour of the complexes. The deviations from planarity increase with increas-

Neutral Nickel(II) and Copper(II) Tetraazamacrocyclic Complexes as Molecular Rods Attached to Gold Electrodes

“…Transesterification of previously described dimethyl esters 1·Ni and 1·Cu [12] with 1,3-propylene glycol in the presence of sodium gave diols 2·Ni and 2·Cu. Treating 2·Ni and 2·Cu with mesyl chloride in the presence of A C H T U N G T R E N N U N G triA C H T U N G T R E N N U N G ethylamine resulted in the formation of dimesyl esters 3·Ni and 3·Cu, which were subsequently transformed into dithiols 5·Ni and 5·Cu after treatment with thiourea.…”

“…The formation of such hostguest complexes with 5·Cu in the gas phase was revealed by analyzing the ESI mass spectra (ESIMS). [12] Herein, we demonstrate that immobilization of the donor unit on the electrode does not remove such interactions; on the contrary it may enhance them and lead to the formation of a pseudorotaxane structure. These observations also indicate the possibility of tuning the donor-acceptor properties of the molecules by interacting them with appropriate ligands in the solution.…”

Synthesis of Trismacrocyclic and Macrotricyclic Compounds Possessing Structural Fragments of Aza- and Diazacrown Ethers, Cyclen and Cyclam via Pd-Catalyzed Amination Reactions

“…dioxane (8 mL), the mixture was stirred for 2-3 min, then corresponding diazacrown ether 15 or 16 (0.15 mmol) and t-BuONa (44 mg, 0.45 mmol) were added, and the reaction mixture was refluxed for 24-30 h. After cooling it down to ambient temperature the reaction mixture was diluted with CH 2 Cl 2 , the residue was filtered off, washed with dichloromethane, combined organic solvents were evaporated in vacuo, the residue was dissolved in CH 2 Cl 2 (5 mL), washed with distilled water (3×10 mL), organic layer was dried over molecular sieves 4 Å and evaporated in vacuo, and the residue was chromatographed on silica gel using a sequence of eluents: CH 2 [19.8.8.5 8,14 .1 2,6 .1 16,20 ]tetratetraconta-2(44), 3,5,16(38), 17,19-hexaene (20). 22, 25,30,7,10,13,19,13 .2 2,5 .2 15,18 ]tetratetraconta -2,4,15,17,36,43-hexaene (21 …”

“…[6] On the basis of these cryptands, mono-and bimetallic homonuclear and heteronuclear complexes were obtained with Cu(II) and Ni(II) cations. [7][8][9][10] 1,8-Ditosylcyclam, 1,8-diBoccyclam and 2,9-dioxocyclam were applied for the synthesis of macrotricycles and macrotetracycles comprising cyclam and porphyrin moieties, [11][12][13] while more sophisticated macropolycles possessing tetraazamacrocycles were obtained using functionalized porphyrins. [14,15] Homo-and heterobinuclear metal complexes with Cu(II), Fe(III) and Co(III) were synthesized on the basis of macrotetracycle and studied as cytochrome oxidase model.…”

Tetraaza[14]macrocyclic Transition Metal Complexes as DNA Intercalators

“…[13,23] The rings are π-electron rich and almost ideally planar. As a consequence, the π-π-stacking can be observed in most of X-ray structures of cyclidene derivatives [14,[23][24][25][26] The solubility of the complexes is determined by functional groups attached to the macrocycle and also depends on the type of counterion used for the crystallisation. However, small monomacrocyclic cyclidenes are usually well soluble in water.…”