Repozytorium

X-ray analyses, spectroscopic and magnetic properties of [Cu4(succinato)(tpmc)2](ClO4)6·2C2H5OH·4H2O and [Cu2(C6H5COO)tpmc](ClO4)3·0.5CH3OH·0.5H2O complexes.

Autorzy

G. Vučkovič

Mirjana Antonijević-Nikolić

Tadeusz Lis

Jerzy Mroziński

Maria Korabik

D. D. Radanovič

Rok wydania

2008

Czasopismo

Journal of Molecular Structure

Numer woluminu

872

Strony

135-144

DOI

10.1016/j.molstruc.2007.02.028

Kolekcja

Naukowa

Język

Angielski

Typ publikacji

Artykuł

Streszczenie

[Cu 4 (succinato)(tpmc) 2 ](ClO 4 ) 6 ·2H 2 O (tpmc=N,N′,N″,N‴-tetrakis-(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane, succinato=dianion of succinic acid) has been prepared and characterized by elemental analysis, UV/vis, IR, EPR (X-band) spectra, conductivity and magnetization measurements (SQUID). Based on a low-temperature measurements (100(2) K), X-ray analyses of the first tetranuclear Cu(II)-tpmc complex, single crystal of which corresponded to the [Cu 4 (succinato)(tpmc) 2 ](ClO 4 ) 6 ·2C 2 H 5 OH·4H 2 O (1) and of the previously described [Cu 2 (C 6 H 5 COO)tpmc](ClO 4 ) 3 ·0.5CH 3 OH·0.5H 2 O (2) were also done. The complexes crystallize in triclinic P1¯ (1) and monoclinic P2 1 /c (2) space groups. The geometry around the first Cu(II) coordination sphere in the tetranuclear complex (1) is almost regular square-based pyramidal, while significant distortion around the other metallic center was observed. The angular structural parameter (τ), which is applicable to five coordinate structures as an index of degree of trigonality, was found to be 0.05 and 0.40, respectively. In the binuclear complex (2) the geometry around the first Cu(II) coordination sphere is regular square-based pyramidal (τ=0.09), while around the other is distorted trigonal bipyramidal (τ=0.79). In complexes (1) and (2) the bridging carboxylate groups are coordinated to metallic centres in a syn–anti mode. Weak ferromagnetic interactions are observed between copper(II) ions, connected through syn–anti monocarboxylate bridges (2J=+1.26 and +1.84cm −1 in complexes (1) and (2), respectively). Additional antiferromagnetic interaction through succinato anion (zJ′=−1.57cm −1 ) gives finally rise to antiferromagnetic interactions, observed in magnetic measurements in tetrameric complex (1).

Adres publiczny

https://doi.org/ 10.1016/j.molstruc.2007.02.028

Strona internetowa wydawcy

http://www.elsevier.com

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