Complexes of Zn(II) and Cd(II) with 2-acetylpyridine -aminoguanidine – Syntheses, structures and DFT calculations

Synthesis and structural characterization of Cd(II) complexes with 2-acetylpyridine-aminoguanidine - a novel coordination mode

“…Cd(II) being prone to form dimeric complexes with bridging coordination of ions. 22 Hence, in the attempt to examine the competitive coordination of these two cations to the ligand, in the reaction of metal chlorides and the chloride ligand salt in the aqueous solution, complex 1 was obtained in the form of yellow prismatic single crystals.…”

“…23 Having in mind the pronounced alkaline nature of the aminoguanidine residue it is not surprising that its Schiff bases in the complexes can have a role of both the ligand and the counter-ion. 22 The survey of Cambridge Structural Database (CSD) 24 revealed 49 complex compounds containing Schiff bases of aminoguanidine. Namely, the majority of these contain the Schiff base coordinated in the tridentate manner (33 structures), while there are only 4 structures with the Schiff base of AG having the role of a tetradentate [25][26][27][28] and only 1 structure in which monodentate 29 coordination was found.…”

“…Up to now several complexes of Cu(II), Zn(II), as well as Cd(II) with the same organic ligand, have been reported. 17,22,30 In these compounds the ligand is present in its neutral form and exhibits tridentate coordination by pyridine N5, azomethine N3 and imino N1 nitrogen of aminoguanidine. The specific feature of 1 and 2 is that the organic ligand is protonated at aminoguanidine nitrogen N1.…”

“…A similar bridge between the octahedrally coordinated Cd(II) centers is rare. It is found in two neutral Cd(II) complexes where the monodentate organic ligands bind next to the Cl (CSD Refcodes: LOYZAC 31 , FOKMEZ 32 ) and also in two anionic species where the water molecules bind next to the Cl ligands (QELLAX 22 and WIPTAQ 33 ). The structures show wide variation in bridging Cd-Cl bond lengths, with values ranging from 2.36 to 2.76 Å, and bridging Cd-Cl-Cd' angles, with values ranging from 91.8 to 105.6 Å.…”

Remarkable colorimetric sensing behavior of pyrazole-based chemosensor towards Cu(ii) ion detection: synthesis, characterization and theoretical investigations

“…[31][32][33] DFT calculations have been widely accepted as indispensable computational tools for prediction of reactive properties of new molecules, complexes and nanomaterials. [34][35][36][37][38][39][40][41] In the present study, we have synthesized and characterized HL and its Cu(II) complexes (1 and 2). Further, the HL is used as colorimetric sensor for the detection of Cu 2+ ion in the presence of various competing ions.…”