Tetraaqua-μ4-(phenylenediaminetetracetato-O1:O2:O3,O4,N:O5,O6,N1)-dicopper(II) dihydrate

Dimer species in dimethyl sulfoxide–water (80∶20 w/w) solution of N,N′-bis(salicylideneimine)-m-phenylenediamine (H2sal-m-phen) and similar Schiff bases with CuII, NiII, CoII and ZnII. Crystal structure of [Co2(sal-m-phen)2]·CHCl3 ‡

“…Species having the ratio ligand : metal 1 : 2 are also obtained, in this case each metal is coordinated to each NO group of the Schiff base. 10 The log K order found for the majority of species was sal-2,4- toluen > sal-m-phen > sal-2,6-toluen. In sal-2,4-toluen the inductive electron-donor effect of the methyl group predominates over the repulsive steric effect, contrarily for sal-2,6-toluen.…”

“…[Ni (20), 312 (19) and 383 (7), peaks of dimer 447 (8) and 767 (21%); diffuse reflectance spectrum 540 nm (LMCT) and 700 nm (LFT). 29 (28), 185 (18), 236 (20), 353 (20) and 367 (24); peaks of dimer: 493 (11), 522 (10) and 578 (3%); diffuse reflectance spectrum 410 nm (LMCT), 582 (LFT) and 750 (br) (LFT). 29 (20), 132 (20), 145 (22), 183 (57), 225 (14) and 326 (9); peak of dimer 430 (15%); diffuse reflectance spectrum 380-410 (LMCT) and 760 nm (LFT).…”

“…These ligands are very versatile and can form monomers, dimers, with excess of metal and with excess of ligand species [equilibria (1)- (10)] with the metals Cu II , Ni II , Co II and Zn II , as shown in Table 2. All these species show different protonation extents.…”

“…Variable-temperature magnetic susceptibility measurements for the solid complexes The preparation of co-ordinating agents derived from aromatic diamines is of special interest since the use of nitrogen atoms for co-ordination of a single cation is directly related to their relative ortho, meta or para positions, as shown for tetramethylcarboxylic acids. [1][2][3][4][5][6][7][8][9][10][11] Thus, for Schiff bases derived from o-phenylenediamines, the proximity of the nitrogen atoms permits simultaneous co-ordination of both to the same metal cation, as has been established by the X-ray crystallographic determination of the structure of the complexes of N,NЈbis(salicylidene)-o-phenylenediamine (H 2 sal-o-phen) with Co II 12 and N,NЈ-bis(salicylidene)toluene-3,4-diamine (H 2 sal-3,4-toluen) with Ni II . 13 These Schiff bases are tetradentate and form complexes basically with a square-planar geometry with these metals.…”

Simulation of Internal Concentration Profiles in a Multimetallic Ion Exchange Process

“…All the possible chelates for copper and cobalt were checked, noting that the metal coordination number was 6 for copper and cobalt in the chelate obtained from a TGA data examination of samples fully saturated with each metal. Thus, the structures proposed for copper and cobalt chelates are those shown in Figure . , …”