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Rational Design of Homo and Hetero Hexanuclear Coordination Compounds: Syntheses and Magnetic Properties of [Cu 2 II M 4 II ] (M = Cu, Ni) Species and the Crystal Structure of {[Cu(tmen)(H 2 O)] 2 [Cu(tmen)] 2 [Cu 2 L](H 2 O)}(ClO 4 ) 4 · 2 H 2 O
Author(s) -
Aukauloo Ally,
Ottenwaelder Xavier,
Ruiz Rafael,
Journaux Yves,
Pei Yu,
Rivière Eric,
Mun˜oz M. Carmen
Publication year - 2000
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(200005)2000:5<951::aid-ejic951>3.0.co;2-r
Subject(s) - cyclam , chemistry , crystallography , intramolecular force , ion , crystal structure , magnetic susceptibility , ligand (biochemistry) , stereochemistry , biochemistry , receptor , organic chemistry , metal
New homo‐ and heterometallic hexanuclear complexes of formula {[Cu(tmen)(H 2 O)] 2 [Cu(tmen)] 2 [Cu 2 L](H 2 O)}(ClO 4 ) 4 · 2 H 2 O [Cu 6 ‐tmen] {[Cu(pmdien)] 4 [Cu 2 L]}(ClO 4 ) 4 · 4 H 2 O [Cu 6 ‐pmdien] and {[Ni(cyclam)] 4 [Cu 2 L]}(ClO 4 ) 4 · 4 H 2 O [Cu 2 Ni 4 ‐cyclam] [H 8 L = tetrakis(aminomethylene)methanetetrakis(oxamic acid), tmen = N,N,N′,N′ ‐tetramethylethylenediamine, pmdien = N,N,N′,N′,N″ ‐pentamethyldiethylenetriamine, and cyclam = 1,4,8,11‐tetraazacyclotetradecane] have been synthesized. The crystal structure of [Cu 6 ‐tmen] has been determined by single‐crystal X‐ray diffraction. The structure consists of cationic {[Cu(tmen)(H 2 O)] 2 [Cu(tmen)] 2 [Cu 2 L](H 2 O)} 4+ hexanuclear units. The hexanuclear cation is made up of two symmetry‐related oxamato‐bridged trinuclear units connected through the central carbon atom C(6) of the L 8– ligand. Variable‐temperature magnetic susceptibility measurements (1.8–300K) have been performed for these series of complexes including the dinuclear precursors of formula Na 4 [Cu 2 L] · 10.5 H 2 O [Cu 2 ‐Na] , (NMe 4 ) 4 [Cu 2 L] · 4 H 2 O [Cu 2 ‐NMe 4 ] and (PPh 4 ) 4 [Cu 2 L] · 6 H 2 O [Cu 2 ‐PPh 4 ] . The magnetic data have been interpreted. Evidence of a weak intramolecular ferromagnetic interaction between the two Cu II ions in [Cu 2 L] 4– has been observed. For the hexanuclear species, the interaction through the oxamato bridge was found to be equal to –6790, –2650, and –1643 yJ (–342, –133, and –82cm –1 ) for [Cu 6 ‐tmen] , [Cu 6 ‐pmdien] , and [Cu 2 Ni 4 ‐cyclam] , respectively. In these complexes, the weak intramolecular ferromagnetic coupling between the two Cu II ions within the dinuclear synthon was masked by intermolecular interactions or local anisotropy.