Polydentate chelates. 3. Structures of egta^4–chelates of manganese(II) and copper(II): Sr[Mn(egta)].7H₂O and [Cu₂(egta)(OH₂)₂].2H₂O

Dinuclear EGTA-copper(II) chelates with imidazole as auxiliary ligand

“…In order to study that and as a part of our program on mixed-ligand Cu(II) complexes with N-heterocyclic auxiliary ligands [13,14], we report the synthesis, structure and properties of compound 1 [15] and its derivatives [Cu 2 (EGTA)(Him) 2 ] n (compound 2) [16] and [Cu 2 (EGTA)(Him) 4 ] AE 4H 2 O (compound 3) [17], which were obtained by reaction of Cu 2 CO 3 (OH) 2 and H 4 EGTA with or without an appropriate amount of Him in water. Our structural data for compound 1 (deposited in the CSD database) agree well with those reported by Dyatlova et al at 283-303 K [10] or by Anderson and Schauer at 143 K [4]. Coordination bond length and selected angles of the studied crystals of compounds 2 and 3 are reported in the legend of Figs.…”

“…On the other hand, it is also known that EGTA acts as a bridging-dinucleating chelating agent for Mg(II) [3], Cu(II) [4,10,11] or W(IV) [12]. In these dinuclear chelates, each half of l 2 -EGTA acts as NO 2 [4,10] and in the closely related mixed-ligand derivative [(en)Cu(l 2 -EGTA)Cu(en)] AE 4H 2 O (compound 4) [11]. The binding of en diamine in 1 to give 4 increases the Cu(II) coordination number (from 4 + 1 to 4 + 1 + 1 * ), the Cu-O(ether) bond length (from 2.409 Å [10] to 2.756(3) Å [11]) and the CuÁ Á ÁCu separation in the dinuclear unit (from 7.052 Å [10] to 7.688 Å [11]).…”

“…In addition of the crystal structure of H 4 EGTA [1] a series of reports concerns the octadentate role of EGTA in metal chelates of the 'hard acid' metal ions Ca(II) [2,3], Sr(II) [3], Ba(II) [3], Mn(II) [4], Cd(II) [2,5], La(III) [6], Ce(III) [6], Nd(III) [7], Gd(III) [8], Dy(III) [6], Ho(III) [6], Er(III) [7], Zr(IV) [9] and Hf (IV) [9]. On the other hand, it is also known that EGTA acts as a bridging-dinucleating chelating agent for Mg(II) [3], Cu(II) [4,10,11] or W(IV) [12]. In these dinuclear chelates, each half of l 2 -EGTA acts as NO 2 [4,10] and in the closely related mixed-ligand derivative [(en)Cu(l 2 -EGTA)Cu(en)] AE 4H 2 O (compound 4) [11].…”

From 1D Polymeric Chain to Two‐fold Parallel Interpenetration of (4,4) Net: Synthesis and Characterization of Two New Copper(II) Complexes Derived from Highly Polydentate Aminopolycarboxylate Ligand

“…In previously reported complexes based on the egta ligand, few examples of an open-up structure (with the µ-bridge) for the egta ligand have been observed and only binuclear entities obtained. 6,9,12,14 However, influenced by auxiliary exo-bidentate bipyridyl ligands, the adjacent [Cu 2 (egta)] entities self-assemble to form the 1D zigzag chain of 1. It should be mentioned that adjacent chains recognize each other to generate a 2D rectangular grid undulating framework parallel to the ac plane via hydrogen bonding between the uncoordinated carboxyl oxygen of the egta and the coordinated water molecules [O(1)…O(4), O(1)…O(6); 0.2702, 0.2817 nm], as shown in Figure 2.…”

“…Moreover, a few examples have been focused on understanding the vital role played by alkali metal ions in biological systems, while relatively little attention has been paid to the transition metal coordination polymers of egta to date. [5][6][7][8][9][10][11][12][13][14] To further understand the influence of transition metal ions on the structure and properties based on egta, here, we report on the synthesis, structures and magnetic properties of two new copper (II) 4,4'-bipyridyl]. Induced by hydrogen bond and dipyridyl spacers with different architectures, the 1D zigzag chain of 1 displays a parallel two-fold interpenetrated (4,4) net topological structure through unique hydrogen-bonded interlocked interactions, while the 1D meso-helix chains of 2 are packed to form a 2D supramolecular structures, which encapsulates a unique 1D water tape consisting of pentamer water clusters.…”