Cylindrical cryptands 2a-c, in which two 1,7-dioxa-4,10-diazacyclododecane rings are connected by two equally substituted propylene bridges, have been obtained in appreciable yields by a 'one-pot' synthesis. The assembling of the macrotricyclic structure is likely driven by the template effect of metal cations. These compounds, both as free receptors or as complexes, exist as cis and trans diastereoisomers, which do not interconvert and have been separated and characterized by X-ray analysis. The extraction constants (K(e)) of cryptands 2 for alkali picrates under CHCl3/H2O and solid/liquid two-phase conditions have been measured by UV-vis spectrophotometry. The complexation behavior of cryptands 2 has been rationalized analyzing the preorganization of binding sites in the minimum energy conformations obtained by molecular mechanics calculations. Minimum energy conformations have been calculated also for the previously reported cryptands 1 and have been compared with those of 2. Results fit reasonably well with those of X-ray structures.

Synthesis and properties of new lipophilic macrotricyclic cylindrical cryptands / S. Quici, A. Manfredi, L. Raimondi, A. Sironi. - In: JOURNAL OF ORGANIC CHEMISTRY. - ISSN 0022-3263. - 60:20(1995), pp. 6379-6388.

Synthesis and properties of new lipophilic macrotricyclic cylindrical cryptands

L. Raimondi;A. Sironi
1995

Abstract

Cylindrical cryptands 2a-c, in which two 1,7-dioxa-4,10-diazacyclododecane rings are connected by two equally substituted propylene bridges, have been obtained in appreciable yields by a 'one-pot' synthesis. The assembling of the macrotricyclic structure is likely driven by the template effect of metal cations. These compounds, both as free receptors or as complexes, exist as cis and trans diastereoisomers, which do not interconvert and have been separated and characterized by X-ray analysis. The extraction constants (K(e)) of cryptands 2 for alkali picrates under CHCl3/H2O and solid/liquid two-phase conditions have been measured by UV-vis spectrophotometry. The complexation behavior of cryptands 2 has been rationalized analyzing the preorganization of binding sites in the minimum energy conformations obtained by molecular mechanics calculations. Minimum energy conformations have been calculated also for the previously reported cryptands 1 and have been compared with those of 2. Results fit reasonably well with those of X-ray structures.
Cage-ligands; nucleic-acids; force-field; sodium; proteins
Settore CHIM/03 - Chimica Generale e Inorganica
Settore CHIM/06 - Chimica Organica
JOURNAL OF ORGANIC CHEMISTRY
Article (author)
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/187233
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 16
  • ???jsp.display-item.citation.isi??? 17
social impact