Mono- and poly-nuclear cryptate complexes of cage-like azamacrocyclic compounds: A thermodynamic and electrochemical approach

Carla Bazzicalupi, Andrea Bencini, Antonio Bianchi, Vieri Fusi, Laura Mazzanti, Piero Paoletti, Barbara Valtancoli, Gilab Golub, Haim Cohen, Dan Meyerstein

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


The compounds 4,7,10,17,23-pentamethyl-1,4,7,10,13,17,23-heptaazabicyclo[11.7.5]pentacosane (L1) and 4,7,10,23-tetramethyl-17-oxa-1,4,7,10,13,23-hexaazabicyclo[11.7.5]pentacosane (L2), respectively comprised of a tetraaza and a monooxatriaza macrocycle overstructured by a triazabridge, formed mononuclear complexes with CuII, ZnII and CdII in aqueous solutions. The co-ordination of these metal ions by L2 has been studied by means of potentiometric and NMR techniques. Thermodynamic and NMR data indicate that the metal ion is accommodated in the N4 and in the N3O fourteen-membered cyclic moiety in the cases of L1 and L2, respectively, while the triaza bridge does not participate in the co-ordination. The complexation of CuI by these macrocycles has been studied by means of electrochemical measurements (cyclic voltammetry); both compounds stabilize the lowvalent copper complexes. This behaviour can be ascribed to the presence of only tertiary nitrogen donors, which leads to a hydrophobic macrocyclic cavity in which the metal ion is encapsulated. Both compounds also form binuclear complexes with CuII in methanol solution. In the case of L1, binuclear assemblies are formed in aqueous solution, allowing for the determination of their stability constants. Mono- and di-hydroxo complexes of the type [M2L1(OH)]+ and [M2L1(OH)2] are formed in aqueous media. The macrobicycle 4,7,10,23-tetramethyl-14-oxo-17-oxa-1,4,7,10,13,23-hexaazabicyclo[11.7.5] pentacosane (L3) has been isolated as its cadmium(II) complex [Cd(HL3)Cl2]ClO4·H2O the crystal structure of which was determined.

Original languageEnglish
Pages (from-to)2377-2384
Number of pages8
JournalJournal of the Chemical Society. Dalton Transactions
Issue number14
StatePublished - 1995
Externally publishedYes


Dive into the research topics of 'Mono- and poly-nuclear cryptate complexes of cage-like azamacrocyclic compounds: A thermodynamic and electrochemical approach'. Together they form a unique fingerprint.

Cite this