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Nature et stabilité des complexes métalliques de cryptands dinucléants en solution. I. Polyazapolyoxa macrotricycle cylindrique et monocycle constitutif
Author(s) -
ArnaudNeu Francoise,
Sanchez Maria,
Yahya Raïda,
SchwingWeill MarieJosé,
Lehn JeanMarie
Publication year - 1985
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19850680219
Subject(s) - chemistry , protonation , cryptand , metal , aqueous solution , cobalt , crystallography , stability constants of complexes , stereochemistry , medicinal chemistry , inorganic chemistry , organic chemistry , ion
Nature and Stability of Some Metallic Complexes of Dinucleating Cryptands in Solution. I. A Polyazapolyoxa Cylindrical Macrotricycle and its Monocyclic Subunit pH‐metry and UV spectrophotometry were used to study the complexing properties of the cylindrical macrotricycle, 1,7,13,19‐tetraaza‐4,16‐dioxa‐10,22,27,32‐tetraoxatricyclo[17.5.5.5]tetratriacontane ( 1 ) and of its constitutive monocyclic subunit, 1,7‐diaza‐4,10‐dioxacyclododecane ( 2 ) with some transition and heavy metal cations (Cu 2+ , Co 2+ , Ni 2+ , Zn 2+ , Cd 2+ , Pb 2+ , Ag + ), in aqueous medium 0.1M Et 4 NClO 4 , at 25°. The protonation constants of the ligands as well as the nature and the stabilities of the complexes formed in the pH‐regions studied were determined. The tricycle 1 only formed dinuclear M 2 L complexes with Cu 2+ , Zn 2+ , and Ag + , accompanied in the latter case by a protonated mononuclear MLH species, and with Cu 2+ and Zn 2+ at high pH‐values by dinuclear hydroxo complexes. Only mononuclear complexes were evidenced with the other cations, ML being accompanied either by protonated or hydroxy mononuclear species. The mononuclear complexes of 1 , when they existed, were more stable than the corresponding complexes of 2 , except for cobalt which formed complexes of comparable stability with both ligands. In the other cases (Cd 2+ , Pb 2+ , Ag + ), the stability differences between the complexes of 1 and 2 increased with the size of the cation.