Related Experiment Video
Updated: Aug 9, 2026
Preparation of Contiguous Bisaziridines for Regioselective Ring-Opening Reactions
Published on: July 28, 2022
Antimony(V) Complexes of an N2O2-Type Tetradentate Azadipyrromethene Ligand and Their Near-Infrared Optical
Tomohiro Agou1, Ryo Moriyama1, Ryo Inoue1
1Graduate School of Science, University of Hyogo, Kamigori-cho, Ako-gun, Hyogo, Japan.
Abstract:
Antimony(V) azadipyrromethene complexes featuring a tetradentate N2O2-type ligand were synthesized to investigate the impact of axial ligands on their photophysical properties. Reaction of the azadipyrromethene ligand with SbCl5 afforded the benchtop-stable dichloro complex aza-LSbCl2 in high yield. Axial ligand substitution enabled the conversion of aza-LSbCl2 to its dihydroxy, chloromethoxy, and dimethoxy derivatives aza-LSb(OH)2, aza-LSbCl(OMe), and aza-LSb(OMe)2, respectively. Photophysical studies revealed a ligand-dependent fluorescence turn-on effect; while the dichloro complex aza-LSbCl2 and the chloromethoxy complex aza-LSbCl(OMe) are nearly nonemissive, the aza-LSb(OH)2 and aza-LSb(OMe)2 exhibit near-infrared (NIR) emission with photoluminescence quantum yields (PLQYs) of 8 and 6%, respectively. Time-dependent density functional theory (TD-DFT) calculations indicate that the fluorescence quenching in the dichloro and chloromethoxy complexes stems from a dissociative excited state characterized by Sb─Cl bond elongation, whereas oxygen-based ligands provide a structurally stable singlet excited state (S1) manifold. These findings demonstrate that post-complexation axial-ligand engineering at the antimony center is an effective strategy for modulating the optical properties of antimony(V) azadipyrromethene complexes, highlighting a distinctive feature not accessible in conventional coordinatively saturated aza-BODIPY systems.
More Related Videos
07:20Amide Coupling Reaction for the Synthesis of Bispyridine-based Ligands and Their Complexation to Platinum as Dinuclear Anticancer Agents
Published on: May 28, 2014
11:44Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds
Published on: October 18, 2018
Related Concept Videos
02:42Valence Bond Theory
03:02Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
02:30Chirality at Nitrogen, Phosphorus, and Sulfur
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
01:11Aryldiazonium Salts to Azo Dyes: Diazo Coupling
02:52Stereoisomerism
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
02:34Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...