Substituent effects on the fluorescent spin-crossover Fe(ii) complexes of rhodamine 6G hydrazones

Abstract

The magnetic properties of Fe(ii) pyridine-2-carbaldehyde rhodamine 6G hydrazone complexes are modulated by the substituents. The desolvated complex displays the correlation between the spin crossover and the fluorescence.

Crystal structure of the mixed methanol and ethanol solvate of bis{3,4,5-trimethoxy-N′-[1-(pyridin-2-yl)ethylidene]benzohydrazidato}zinc(II)

“…The aroylhydrazone ligands can form charged complexes or can easily be deprotonated due to tautomerism, thus forming neutral species. These dynamic reversible properties have led to the exploration of charged and neutral spin-crossover iron(II) and iron(III) complexes, some with multifunctional properties (Zhang et al, 2010;Shongwe et al, 2012;Romero-Morcillo et al, 2015;Yuan et al, 2019). As part of our continuing interest in studying 3d metal complexes formed by polydentate ligands bearing alkoxy substituents (Seredyuk, 2012;Seredyuk et al, 2006Seredyuk et al, , 2011Seredyuk et al, , 2016 and those based on polydentate ligands (Seredyuk et al, 2007(Seredyuk et al, , 2015, we report here the synthesis and crystal structure of a neutral Zn II complex formed with the tridentate ligand 3,4,5-trimethoxy-N 0 -[1-(pyridin-2-yl)ethylidene]benzohydrazide.…”

Controlled Synthesis of Luminescent Xanthene Dyes and Use of Ionic Liquid in Thermochromic Reaction

“…Although they have excellent spectroscopic properties (e.g., high quantum yields ~95%), some problems are also noticeable. They may photodecompose during heating [ 17 ], having relatively short luminescence lifetimes (around 4 ns) [ 18 ] for imaging applications [ 19 , 20 , 21 , 22 , 23 , 24 ]. It is, however, possible to modify the dye structure to change the luminescent properties (absorption and emission ranges).…”

“…The reaction can be reversible or irreversible ( Figure 1 A). Fluorans can therefore be considered functional compounds that can be used in thermo-, pH−, or pressure-sensitive recording systems [ 10 , 20 , 44 , 45 , 46 ]. The main two groups of leuco dyes based on fluoran skeletons possess different groups attached in position 6′ or positions 3′ and 6′ ( Figure 1 B).…”

Cation modulated spin state and near room temperature transition within a family of compounds containing the same [FeL2]2− center

“…The SCO behaviors can be manipulated by the substituent groups of the ligands, replacement of the counter-ions, and capture and release of the solvent molecules. 33,43–54 In reference to the counter-ion modulation, major works are devoted to the substitution of anions, but few reports are dedicated to organic amine cation alternation, even though organic amines span a broad range of molecular sizes, shapes, symmetries, and number of NH⋯X (X = acceptor atoms) hydrogen bonds. This is because the charge of most SCO mononuclear compounds in the literature is either neutral or positive, and SCO mononuclear compounds with a negative charge are extremely scarce.…”