Room-Temperature Magnetic Liquid Complexes of 2-Hexyldecanoato Ligand with Cu(II), Ni(II) and Co(II) Ions

Abstract

Most of transition metal(II) carboxylates were reported to exist as multinuclear complexes due to the multibinding modes of the ligands 1,2. For example, most of the copper(II) carboxylates were dinuclear with the paddle-wheel structure 3-7 , while other metal(II) complexes (Mn, Co, Ni and Zn) were found to form polymeric structures 8-11. Hence, these complexes are attracting the interests of many researchers in various fields, such as catalysis, molecular electronics and molecular magnetism. The main reason is because they are easily prepared from relatively low cost, nontoxic and readily accessible starting materials and readily characterized by conventional analytical methods. However, these complexes are yet to be commercially used as functional materials due to physical limitations, such as insolubility, high-melting and low-decomposition temperatures. Currently, our research group is focused on designing, synthesizing and characterizing thermally stable and low melting temperatures magnetic metal(II) carboxylates to function as molecular magnetic, photonic and electronic materials and as precursors for functional coordination polymers. This paper reports the synthesis, structural, magnetic, thermal, optical and redox properties of three complexes of 2-hexyldecanoato ligand (L) with Cu(II) (1), Ni(II) (2) and Co(II) (3). These complexes were obtained as room-temperature viscous liquids from the reaction of NaL with the

Structures and mesomorphism of complexes of tetrakis(4-chlorobenzoate-μ-O,O′)bis(ethanol)dicopper(II) with different N-donor ligands

“…Since these data were similar to crystals of copper(II) complexes with the dimeric paddle-wheel structures reported in the literature [12][13][14][15] (table 3), we inferred that 1 also has this structure. The effective magnetic moment (μ eff ) for 1 was 1.8 BM at 300 K. The value was determined by the Gouy method, and calculated for the dimer using the equation:…”

“…This suggested a strong antiferromagnetic interaction between the Cu(II) ions in this complex. The value was also higher than reported for [Cu 2 (CH 3 (CH 2 ) 5 COO) 4 ] (1.6 BM) [14] and [Cu 2 (CH 3 COO) 4 (tnz) 2 ] (tnz = tinidazole; 1.3 BM) [15], suggesting a weaker antiferromagnetic interaction between the two Cu(II) atoms in 1. We ascribed this to the differences in the electronic effect of the group bonded to -COO of the carboxylate and the type of donor atom of the apical ligand (N-donors are stronger Lewis bases than O-donors).…”

“…The peak separations (560-1050 mV) far exceeded the theoretical value for a reversible one-electron redox process (56 mV at 298 K [48]), indicating quasireversible redox processes and hence extensive structural changes. These results were similar to [Cu 2 (C 6 H 5 COO) 4 (EtOH) 2 ] (E pc = −0.13 V, −0.35 V, and −0.74 V; E pa = +0.31 V, +0.46 V) [37], but quite different from [Cu 2 (4-ClC 6 H 4 CH 2 COO) 4 (pyr) 2 ] (E pc = −0.61 V; E pa = +0.66 V) [13] and [Cu 2 (CH 3 COO) 4 (tnz) 2 ] (E pc = −0.12 V; E pa = +0.20 V) [15]. From these, we infer that the dimers partially dissociated to monomers in these solvents prior to the redox process(es) (scheme 2).…”

“…Most copper(II) carboxylates are dimeric and have paddle-wheel structures [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. From EXAFS data, it was inferred that the dimers were linked into a 1-D oligomeric chain in the solid state [17], and remained intact in solutions [18,19].…”

Photophysical and Electrochemical Studies of Multinuclear Complexes of Iron(II) with Acetate and Extended Conjugated N‐Donor Ligands

“…The peaks were weak due to the presence of eight 14-carbon linear alkyl chains acting as an “insulating” layer for the transfer of electrons to/from the electrode surface [21]. The potential separation (Δ E ) between the anodic and cathodic peaks was 1150 mV, and the cathodic-to-anodic peak current ( I pc / I pa ) was close to unity.…”