Amphiphilic copper(II) complexes modeled after the metal-complexation subunit of bleomycin antibiotics

Giovanna Ghirlanda, Paolo Scrimin, Paolo Tecilla, Antonio Toffoletti

Research output: Contribution to journalArticle

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Abstract

A series of lipophilic ligands, structurally related to Bleomycins (BLMs) metal-binding subunit, have been synthesized. They comprise a 4-alkoxypyridine substituted in the 2- and 6-positions with methylhistamine or methylethylenediamine moieties. With respect to native BLMs, pyridine replaces the pyrimidine ring and the amide function in one of the two sidearms has been reduced to amine. Long hydrocarbon chains in the alkoxy moiety provide lipophilicity. Hydrophilic ligands were also synthesized to get insight on the effect of micellization upon protonation and complex formation. All ligands form 1:1 complexes with Cu II ions, and those of the lipophilic ligands form micellar aggregates (metallomicelles) with critical micelle concentrations (cmc) in the 9 × 10 -5-1.4 × 10 -4 M concentration interval. Micellization affects acid/base and coordination equilibria as well, as suggested by titration, 1H NMR, and UV-vis spectroscopic investigations, but does not affect the geometry of coordination. The information obtained indicates that, upon micellization, the amines become less basic although the difference in basicity between aggregate and nonaggregate systems tends to disappear with the proceeding of the protonation. Micellization affects the pH at which the complexes switch from tetra- to pentacoordinate: this explains the pH and aggregation-dependence of the redox potential of the Cu II/Cu I couple we have previously reported (Langmuir 1996, 12, 5188) for these systems.

Original languageEnglish
Pages (from-to)1646-1655
Number of pages10
JournalLangmuir
Volume14
Issue number7
Publication statusPublished - Mar 31 1998

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Micellization
antibiotics
Bleomycin
Antibiotics
Complexation
Copper
Metals
Ligands
Anti-Bacterial Agents
copper
ligands
Protonation
metals
Amines
amines
Methylhistamines
Critical micelle concentration
pyrimidines
Alkalinity
Hydrocarbons

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

Cite this

Amphiphilic copper(II) complexes modeled after the metal-complexation subunit of bleomycin antibiotics. / Ghirlanda, Giovanna; Scrimin, Paolo; Tecilla, Paolo; Toffoletti, Antonio.

In: Langmuir, Vol. 14, No. 7, 31.03.1998, p. 1646-1655.

Research output: Contribution to journalArticle

Ghirlanda, G, Scrimin, P, Tecilla, P & Toffoletti, A 1998, 'Amphiphilic copper(II) complexes modeled after the metal-complexation subunit of bleomycin antibiotics', Langmuir, vol. 14, no. 7, pp. 1646-1655.
Ghirlanda, Giovanna ; Scrimin, Paolo ; Tecilla, Paolo ; Toffoletti, Antonio. / Amphiphilic copper(II) complexes modeled after the metal-complexation subunit of bleomycin antibiotics. In: Langmuir. 1998 ; Vol. 14, No. 7. pp. 1646-1655.
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