A new tetraiminodiphenol macrocyclic ligand and its two dicopper(II) complexes: Syntheses, crystal structures, electrochemistry and magnetochemistry
- Autor(en)
- Samit Majumder, Michel Fleck, C. Robert Lucas, Sasankasekhar Mohanta
- Abstrakt
This paper deals with the diprotonated salt, [H4L](ClO4)2 (1), of the tetraiminodiphenolate macrocyclic ligand, H2L which is the [2 + 2] condensation product of 4-ethyl-2,6-diformylphenol and 2,2'-dimethyl-1,3-diaminopropane, and two diphenoxo-bridged dicopper(II) complexes [Cu2L(ClO4)2] (2) and [Cu2L(ClO4)](ClO4) (3). The syntheses, characterization and crystal structures of 1-3 and the magnetic and electrochemical properties of the metal complexes 2 and 3 are presented. The cationic macrocycle [H4L]2+ is stabilized by four intramolecular and symmetric Nsingle bondH-O-Hsingle bondN hydrogen bonds involving phenoxo oxygen and imino nitrogen atoms. One metal center in 3 is tetracoordinated and in a square planar geometry. The second metal ion of 3 and both the metal ions in 2 are pentacoordinated and in a square pyramidal geometry; one perchlorate oxygen atom occupies the apical position in each case. Both 2 and 3 exhibit quasireversible two-step one-electron couples in the reduction window. The E½ (?Ep) values (in mV) for the CuIICuII/CuIICuI couple is -0.466 V (0.067 V) for 2 and -0.490 V (0.076 V) for 3, while the E½ (?Ep) values (in mV) for the CuIICuI/CuICuI couple is -0.953 V (0.060 V) for 2 and -0.985 V (0.069 V) for 3. Variable-temperature (2-300 K) magnetic susceptibility measurements of the two compounds reveal that the metal centers in both of the complexes are coupled by strong antiferromagnetic interactions with 2J values (H = -JS1·S2) of -780 and -820 cm-1 for 2 and 3, respectively.
- Organisation(en)
- Institut für Mineralogie und Kristallographie
- Externe Organisation(en)
- University of Calcutta, Memorial University of Newfoundland
- Journal
- Journal of Molecular Structure
- Band
- 1020
- Seiten
- 127-133
- Anzahl der Seiten
- 7
- ISSN
- 0022-2860
- Publikationsdatum
- 2012
- Peer-reviewed
- Ja
- ÖFOS 2012
- 105113 Kristallographie
- Link zum Portal
- https://ucrisportal.univie.ac.at/de/publications/ca998eee-ccd8-4e0a-9a00-05bdd45b952f