Self-Assembly of Two Novel Cadmium(II) Complexes: One from Tripodal Imine−Phenol Ligand and the Other from In situ Partial Degradation of Dipolar Imine−Phenol Ligand

Abstract

Through different synthetic strategies, two novel cadmium(II) complexes have been synthesized and characterized. The first mesocate complex Cd3L1 2 (1) with S 6 symmetry based on tris[(2-salicylaldeneimino)ethyl]-amine (H3L1 or H3trensal) is constructed from the self-assembly of Cd2+ ion and two chiral building block units, Δ- and Λ-[Cd(trensal)]−, in which the coordination numbers of six and seven for Cd(II) ions are rarely found in one discrete compound without any auxiliary ligand. However, under the same reaction conditions, CdL3(H2O)(NO3) (2) with N3O4 donors is obtained from CdII coordination induced partial hydrolysis of dipolar imine−phenol Schiff base ligand N,N′-bis(salicylidene)-3, 6-dioxa-1,8-diaminooctane (H2L2), which provides the first example of hydrated CdII salt promoting partial degradation of the imine−phenol ligand. The strong fluorescence emission of 1 makes it a potentially useful photoactive material for its high thermal and chemical stability.

A Useful Route to Metal Complexes of Poorly Coordinating Sulfonamides

“…A cleavage mechanism similar to that previously reported for the partial hydrolysis of an imino-phenol ligand mediated by Cd 2+ ions must be also operative in the present case. [26] Next, the reactivity of the ring tautomer H 2 L TQ towards both Zn 2+ and Cd 2+ ions was also studied in an aprotic solvent (Scheme 2). For this purpose, we used an electrochemical method, [23] through which the protons potentially available in the medium were reduced to dihydrogen, as release of this gas could be detected during the syntheses.…”

Two 3D supramolecules with helices constructed by hydrogen bonds based on p-thioacetatebenzoic acid ligand

“…The enhancement of luminescence in the coordination may be attributed to the rigidity of them. The coordination enhances the ''rigidity'' of the ligand and thus reduces the loss of energy through a radiationless pathway [45] (Fig. 9).…”

Anion Effect on the Formation of Zinc‐Salicyaldimine Compounds in Neutral and Anionic Complex Forms: Synthesis, Characterization, 1H NMR Studies, and Photophysical Properties

“…Salicyaldimines, also called salicylaldehyde Schiff bases or imine-phenol Schiff bases, [1] are half-salen-type ligands showing coordinate properties similar to that of 8-hydroxyquinoline since those ligands usually demonstrate the chelation of imine nitrogen atom and phenoxo oxygen atom to metal center, [2] i. e., a N,O-chelating systems in coordination chemistry. In addition, salicyaldimines and 8-hydroxyquinoline have similar delocalized π-systems which result in an analogy between the emission behaviors of both types of compounds.…”