Synthesis, Crystal Structures, and Magnetic Properties of Two Novel Cyanido-Bridged Heterotrimetallic {CuIIMnIICrIII} Complexes.
The self-assembly process between the heteroleptic [CrIII(phen)(CN)4]-and [CrIII(ampy)(CN)4]-metalloligands and the heterobimetallic {CuII(valpn)MnII}2+tecton afforded two heterotrimetallic complexes of formula [{CuII(valpn)MnII(μ-NC)2CrIII(phen)(CN)2}2{(μ-NC)CrIII(phen)(CN)3}2]·2CH3CN (1) and {[CuII(valpn)MnII(μ-NC)2CrIII(ampy)(CN)2]2·2CH3CN}n(2) [phen = 1,10-phenanthroline, ampy = 2-aminomethylpyridine, and H2valpn = 1,3-propanedyilbis(2-iminomethylene-6-methoxyphenol)]. The crystal structure of 1 consists of neutral CuII2MnII2CrIII4octanuclear units, where two [Cr(phen)(CN)4]-anions act as bis-monodentate ligands through cyanide groups toward two manganese(II) ions from two [CuII(valpn)MnII]2+units to form a [{Cu(valpn)Mn}2Cr2(CN)4]6+square motif. Two [Cr(phen)(CN)4]-pendant anions in 1 are bound to the copper(II) ions with cis-trans geometry with respect to the bridging [Cr(phen)(CN)4]-anion. Compound 2 is a sheet-like coordination polymer, where chains constituted by {CrIII(ampy)(CN)4} spacers act as bis-monodentate ligands toward the manganese(II) ions belonging to the {CuII(valpn)MnII} nodes, which are interlinked by another {CrIII(ampy)(CN)4} unit that acts as a bridge between the copper(II) and manganese(II) ions of adjacent chains. Magnetic susceptibility measurements in the temperature range of 1.9-300 K were performed for 1 and 2. An overall antiferromagnetic behavior is observed for 1, the ground spin state being described by a spin triplet from the square motif plus two magnetically isolated spin triplets from the two peripheral chromium(III) ions. Ferrimagnetic chains with interacting spins 1/2 (resulting spin of the trimetallic {CuII(valpn)MnII(μ-NC)CrIII} fragment) and 3/2 (spin from the bis-monodentate [CrIII(ampy)(CN)4]-with weak interchain ferromagnetic interactions across the cyanide bridge between the chromium(III) and the copper(II) ion from adjacent chains [θ = +3.83(2) cm-1]) occur in 2, resulting into a ferromagnetic ordering below 3.5 K. The values of the magnetic coupling between the Cu(II) and Mn(II) ions through the double phenoxide bridge [J = -63.1(2) (1) and -62(3) cm-1(2)] and those between the Cr(III) and the Mn(II) across the single cyanide bridge [J = -7.08(5) and -4.86(6) cm-1(1) and -8.59(3) cm-1(2)] agree with the values reported for these exchange pathways in other magnetostructural studies.
Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest , 1-7 Gh. Polizu Street, 01106 Bucharest, Romania.
Maria-Gabriela
MG
Alexandru
Coordination and Supramolecular Chemistry Laboratory, "Ilie Murgulescu" Institute of Physical Chemistry, Romanian Academy , Splaiul Independentei 202, Bucharest 060021, Romania.
Diana
D
Visinescu
"Petru Poni" Institute of Macromolecular Chemistry, Romanian Academy , Aleea Grigore Ghica Vodă 41-A, RO-700487 Iasi, Romania.
Sergiu
S
Shova
Inorganic Chemistry Laboratory, Faculty of Chemistry, University of Bucharest , Str. Dumbrava Rosie 23, 020464 Bucharest, Romania.
Marius
http://orcid.org/0000-0001-8224-4866
M
Andruh
Departament de Química Inorgànica/Instituto de Ciencia Molecular, Universitat de València , C/Catedrático José Beltrán 2, 46980 Paterna, València, Spain.
Francesc
F
Lloret
Departament de Química Inorgànica/Instituto de Ciencia Molecular, Universitat de València , C/Catedrático José Beltrán 2, 46980 Paterna, València, Spain.
Miguel
M
Julve