Isoindoline-derived ligands and applications

Abstract

REVIEW This journal isDuring the past decade isoindoline-based ligands became subject of growing interest due to their modular set-up. In this review the structure and reactivity of these ligands and their transition metal complexes are covered. Beyond the discussion of the structural properties particular attention is paid to the expanding fields of applications of these compounds.

Joining Chromophores: a Porphyrin‐BPI Fused System

“…In the last decade, the syntheses of such BPIs have attracted significant interest, due to their tunable and versatile structure, which makes them suitable building blocks for the construction of more complex molecular architectures. The applications of BPIs span different fields, ranging from materials science to asymmetric catalysis . The synthesis of BPI derivatives is extremely versatile, allowing easy access to a large variety of compounds through the fine‐tuning of the substituents on both the isoindolato backbone and pendant pyridine rings, owing to their modular assembly.…”

“…For this compound we obtained X-ray quality crystals by the slow diffusion of methanol into a dichloromethane solution ( Figure 3). During the crystal growth a trans-esterification process occurred and the crystallographic structure shows a meth- The second fraction collected corresponded to the desired functionalized ZnTPP-BPI (5), obtained in 31 % yield. To avoid the competition between solvent and reagent in the nucleophilic attack upon the iminoisoindoline, the reaction was run by replacing butanol with toluene, and with the simple and cheaper 2-NH 2 -pyridine as building block for the porphyrin-BPI formation.…”

“…The applications of BPIs span different fields, ranging from materials science to asymmetric catalysis. [2][3][4][5][6] The synthesis of BPI derivatives is extremely versatile, allowing easy access to a large variety of compounds through the fine-tuning of the substituents on both the isoindolato backbone and pendant pyridine rings, owing to their modular assembly. Generally BPIs are synthesized following the Elvidge and Linstead procedure, [7][8][9] involving the condensation of diiminoisoindoline and 2-aminopyridine in boiling butanol; an alternative and cheaper approach uses phthalonitrile [10,11] as starting material (Scheme 1), thus avoiding the critical step of isoindoline preparation.In general, pyridine-arm isoindolines might coordinate metal ions as tridentate pincer ligands either as deprotonated anions, or (in one instance) as the iminium zwitterion.[a] 655 phyrin complex was then subject to Zn ion removal from the porphyrin core, allowing the isolation of the corresponding free base derivative.…”

1,3-Bis(5′-methyl-4′-phenyl-2′-thiazolylimino)isoindoline

“…The ligand family originates from diiminoisoindolines and phthalocyanines that are building blocks of supramolecular architectures. It has been proven in a couple of biological studies that they may possess antiproliferative activity and they can act as diuretic or blood pressure regulator agents [1]. BAI with thiazole arms can add an extra function to transition metal complexes they coordinate to.…”

“…Bulky aliphatic or aromatic functional groups on the thiazole arm can easily block homoleptic complex formation that is characteristic for isoindoline complexes [1]. This can create an advantageous situation for cyclometallation [3] or intramolecular oxidative CH bond (benzylic and/or aromatic) activation reactions via peroxo or high valent oxo species [4].…”