The 14-membered macrocyle 1,4,8,1 1-tetraazacyclotetradecane (cyclam), a weIl-known N4-donor cyclic system, exhibits great flexibility in accommodating a range of host metal ions and five different arrangements of the chiral nitrogen donor centers are possible in the resulting complexes (Lindoy, 1989). For instance, in cis-[CrCl2(cyclam)]+ (House and McKee, 1984) the absolute configuration is of the type (RRRR), in trans-[ReO2(cyclam)]+ (Luna et al., 1992) it is (RSSR), while in cis-[MoCl2(cyclam)]+ (Hyldtoft et al., 1989) it is (RSRR). In order to gain a deeper understanding of the flexibility of cyclam and of its doubly protonated form, H2cyclam2+, we evaluated the energy content of all conformations. In addition, we present the crystal structure of [H2cyclam] [O3SCF3]2 and a comparison with the data found in [H2cyclam] [ClO4]2 (Nave and Truter, 1974) is reported.

Structural investigation of [H2cyclam] [O3SCF3]2 (cyclam=1,4,8,11-tetraazacyclotetradecane)

BANDOLI, GIULIANO;DOLMELLA, ALESSANDRO;
1993

Abstract

The 14-membered macrocyle 1,4,8,1 1-tetraazacyclotetradecane (cyclam), a weIl-known N4-donor cyclic system, exhibits great flexibility in accommodating a range of host metal ions and five different arrangements of the chiral nitrogen donor centers are possible in the resulting complexes (Lindoy, 1989). For instance, in cis-[CrCl2(cyclam)]+ (House and McKee, 1984) the absolute configuration is of the type (RRRR), in trans-[ReO2(cyclam)]+ (Luna et al., 1992) it is (RSSR), while in cis-[MoCl2(cyclam)]+ (Hyldtoft et al., 1989) it is (RSRR). In order to gain a deeper understanding of the flexibility of cyclam and of its doubly protonated form, H2cyclam2+, we evaluated the energy content of all conformations. In addition, we present the crystal structure of [H2cyclam] [O3SCF3]2 and a comparison with the data found in [H2cyclam] [ClO4]2 (Nave and Truter, 1974) is reported.
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: https://hdl.handle.net/11577/2495703
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 6
  • ???jsp.display-item.citation.isi??? 6
social impact