ic301744e_si_002.cif (172.64 kB)
Employment of a New Tripodal Ligand for the Synthesis of Cobalt(II/III), Nickel(II), and Copper(II) Clusters: Magnetic, Optical, and Thermal Properties
dataset
posted on 2012-10-01, 00:00 authored by Angelos
B. Canaj, Demetrios I. Tzimopoulos, Aggelos Philippidis, George E. Kostakis, Constantinos J. MiliosThe employment of 2-(β-naphthalideneamino)-2-(hydroxymethyl)-1-propanol
(LH3) in cobalt, nickel, and copper chemistry has led to
the isolation of five new metallic complexes with interesting magnetic
properties. More specifically, the reaction of Co(OAc)2·4H2O with LH3 in MeOH in the presence
of NEt3 under solvothermal conditions forms the complex
[CoIII2CoII3(L)2(LH)2(L′)(OAc)]·8.5MeOH (1·8.5MeOH;
L′ = monoanion of 2-hydroxy-1-naphthaldehyde), while in nickel
chemistry, a similar reaction of Ni(OAc)2·6H2O with LH3 in MeCN in the presence of NEt3 under
high pressure/temperature forms the complex [NiII(LH2)2]·2MeCN (2·2MeCN). Repeating
the same reaction in MeOH and switching from Ni(OAc)2·4H2O to NiSO4·4H2O produces the complex
[NiII4(HL)3(OMe)(MeOH)3](SO4)0.5·2MeOH (3·2MeOH)
under solvothermal conditions. Furthermore, in copper chemistry, the
reaction of Cu2(OAc)4·2H2O with
LH3 in the presence of NEt3 in MeOH under solvothermal
conditions affords the complex [CuII4(LH)4] (4), while the same reaction under ambient
temperature and pressure conditions forms [CuII4(LH)4] ·3.5MeOH·2.25H2O (5·3.5MeOH·2.25H2O). Complex 1 is
a mixed-valent [CoIII2CoII3] complex, consisting of three edge-sharing [Co3] triangles.
Complex 2 is a nickel(II) monomer in which the central
metal is found in an octahedral geometry, while complex 3 describes a [NiII4] cubane. Complexes 4 and 5 may be considered as structural isomers
because they possess the same formulas but different topologies: 4 describes a highly distorted [CuII4(OR)4]4+ eight-membered ring, while 5 consists of a distorted [CuII4(μ3-OR)4]4+ cubane. In addition, 5 can be converted to 4 in excellent yield under
solvothermal conditions. Direct-current magnetic susceptibility studies
have been carried out in the 5–300 K range for complexes 1 and 3–5, revealing the
possibility of a high-spin ground state for 1, an S = 4 ground state for 2, and diamagnetic ground
states for 4 and 5.