endo- versus exo-Cyclic coordination in copper complexes with methylthiazolylcarboxylate tacn derivatives

Abstract

We explore the impact of methylthiazolylcarboxylate pendant arms on the endo-or exo-cyclic coordination of Cu(ii) with tacn derivatives.

Is Less More? Influence of the Coordination Geometry of Copper(II) Picolinate Chelate Complexes on Metabolic Stability

“…The axially elongated octahedron of Cu(3) is comprised of an equatorial plane of nitrogen and oxygen donors from the dissociated picolinate arms from mpatcn bound to Cu(1) and Cu(2) [N(4), O(1) and N(8), O(7), respectively], while the elongated apical sites are μ 2 -1,1-carboxylates from mpatcn [O(5) and O(9)]. As noted, a similar trinuclear structural motif is observed for the triazacyclononane-based chelates no2th1tha and no3tha; however, the apical sites of these elongated octahedra are oxygen atoms of the perchlorate counterion rather than a bridged carboxylate …”

“…This is similar to the trinuclear species detected during potentiometric and X-ray diffraction studies for a mixed heterocycle/carboxylate chelate based on triazacyclononane, Cu(no2th1tha). 24,36 In our hands, we have not been able to obtain X-ray-quality single crystals of the mononuclear complex [Cu(mpatcn)] − ; however, the desired mononuclear species is the dominant species in solution with stoichiometric or excess ligand. The formation of a 3:2 metal/ligand complex under radiochemical-labeling conditions is strongly disfavored because typical conditions involve a metal/ligand ratio of 1:100 or 1:1000.…”

“…As noted, a similar trinuclear structural motif is observed for the triazacyclononane-based chelates no2th1tha and no3tha; however, the apical sites of these elongated octahedra are oxygen atoms of the perchlorate counterion rather than a bridged carboxylate. 36 Computational Studies. While an initial snapshot of the possible binding modes of nompa, nompa-ac, and mpatcn with copper(II) was provided by single-crystal X-ray diffraction experiments, a detailed investigation of the possible solution structures was pursued using DFT.…”

A Six‐Armed Phenhomazine Ligand with a Potential “Turn‐Off” Copper(II) Sensing Capability through Terbium(III) Luminescence Quenching

“…To get a deeper insight concerning the coordination mode of Cu II with 1 , a new titration was performed by using 1 H NMR spectroscopy. Owing to the paramagnetic nature of Cu II , the diamagnetic ion Zn II was used as a model, as several reports show that the coordination mode and stoichiometry should not vary substantially between these two ions …”

Complexes of NOTA‐Monoamides with CuII Ions: Structural, Equilibrium, and Kinetic Study

“…[1][2][3][9][10][11] However, several tacn derivatives with other coordinating pendant arms have been investigated as chelators for copper radionuclides. [1][2][3][4][5][6][7][8][9][12][13][14][15][16][17][18][19][20] Complexes of H 3 nota, as highly hydrophilic and lowmolecular-weight compounds, show a non-specific uptake in organs and a fast body clearance. To reach the desired biodistribution, these complexes are conjugated to biologically active targeting vectors.…”