Illuminating Metal-Ion Sensors: Benzimidazolesulfonamide Metal Complexes

Abstract

The synthesis, structure, and solution spectroscopy of several 2-sulfonamidophenylbenzimidazole metal complexes is reported. These ligands, which have been reported as selective molecular sensors for Zn2+, readily form complexes with Co2+, Ni2+, Cu2+, and Zn2+. Surprisingly, the ligand adopts different binding modes depending on the metal ion. The work here provides insight into the coordination chemistry of these ligands that may allow for the development of improved metal ion sensors and metalloprotein inhibitors.

High-Throughput Small-Molecule Crystallography at the ‘Belok’ Beamline of the Kurchatov Synchrotron Radiation Source: Transition Metal Complexes with Azomethine Ligands as a Case Study

“…The full list of geometrical parameters for 1-Fe is available as Supplementary Materials. The molecular structure of 1-Fe is relatively simple and similar to a series of other related compounds characterized earlier [64][65][66][67][68][69][70][71].…”

“…The bond angles within the ZnN4 core range from 91.9(3) to 146.4(3), with a dihedral angle between the flattened six-membered chelating rings (rms deviations are 0.070 and 0.101 Å) of 78.3(2). It is interesting to note that the intramolecular secondary Zn···O interactions in 2-Zn are substantially shorter and, consequently, the degree of distortion of the ZnN4 tetrahedron is larger than those observed in related zinc complexes [64,67,70]. This fact can be explained by specific packing effects due to the intermolecular hydrogen bonds (Table 2, Figure 4).…”

Investigating chelating sulfonamides and their use in metalloproteinase inhibitors

“…The result is that while the sulfonamide moiety of compound BIS1 generates a 6-membered chelate ring when bound to a metal ion, ZBG2 and ZBG4 will form a 5-membered chelate similar to that for ZBG3 or QS1 . Thus, ZBG2 and ZBG4 are structurally related to compound BIS1 but certain features similar to QS1 , making these ZBGs a hybrid our two earlier scaffolds (18, 27). Although the ZBG2 derivatives did not show any activity against MMP-2 or MMP-9 at 50 µM, most of the ZBG4 derivatives were active against both MMP-2 and MMP-9, with one compound ( ZBG4b ) giving an IC 50 of 40 µM against MMP-2.…”

“…While ZBG1 and ZBG3 were synthesized as analogues to compound QS1, ZBG2 and ZBG4 were synthesized to gain more insight around the phenylbenzimidazole sulfonamide ZBG found in compound BIS1 (27). ZBG2 and ZBG4 essentially preserve the steric and electronic features of compound BIS1 , but place the sulfonamide substituent in a position on the chelator that is more similar to that found in ZBG1, ZBG3 , and compound QS1 .…”

Synthesis, structural and optical properties of 1-alkyl-2-(2’-tosylaminophenyl)-5-nitrobenzimidazoles and their zinc(II) complexes

“…Besides, the replacement of tosyl amino group in the ortho-position of benzolic ring by hydroxy group allowed obtaining the zinc complexes with {ZnN 4 } coordination core. Based on the 2-(2'-tosylaminophenyl)benzimidazoles derivatives the very efficient selective fluorescent metal-ions (Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ ) sensors [14][15][16] were prepared.…”