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Hydrolysis of a Ni-Schiff-Base Complex Using Conditions Suitable for Retention of Acid-labile Protecting Groups
Published on: April 6, 2017
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Transmetalation for Flexible Pendant-Armed Schiff-Base Macrocyclic Complexes Influenced by Halide Effects
Fei-Fan Chang1, Lei Zhang1, Pei-Chen Zhao1
1State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing 210093, People's Republic of China.
Inorganic Chemistry
|January 12, 2018
Summary
This study synthesized novel Schiff-base macrocyclic complexes of cadmium and copper, investigating their transmetalation reactions. Halide ions significantly influenced the resulting complex structures and reaction outcomes.
Area of Science:
- Coordination Chemistry
- Supramolecular Chemistry
- Materials Science
Background:
- Schiff-base macrocycles are versatile ligands in coordination chemistry.
- Template-directed synthesis offers control over macrocycle formation.
- Metal ion templating and halide effects are crucial in macrocyclic complex assembly.
Purpose of the Study:
- To synthesize novel pendant-armed Schiff-base macrocyclic dinuclear cadmium(II) and copper(II) complexes.
- To investigate the transmetalation reactions of these macrocycles with other metal ions (Zn(II), Cd(II), Cu(II)).
- To elucidate the role of halide ions (Cl-, Br-) in directing the structural organization and reactivity of the macrocyclic complexes.
Main Methods:
- Template-directed condensation reactions using 1,2-bis(2-aminoethoxy)-ethane and extended Cl-dialdehyde.
- Synthesis of [2+2] and [1+1] macrocyclic complexes with Cd(II) and Cu(II) ions.
- Transmetalation studies involving pre-synthesized Zn(II) and Cd(II) macrocycles.
- Electrospray Ionization Mass Spectrometry (ESI-MS) for intermediate detection.
Main Results:
- Successfully synthesized three 46-membered [2+2] dinuclear complexes (2a, 2b, 3b) and one 23-membered [1+1] macrocycle (4a).
- Observed irreversible transmetalation reactions: Zn(II) → Cu(II) and Cd(II) → Cu(II) were faster than Cd(II) → Zn(II).
- Demonstrated distinct halide effects: CuCl2 promoted conversion to [1+1] macrocycles and configurational changes, while CuBr2 favored efficient formation of [2+2] dinuclear Cu(II) complexes.
Conclusions:
- Halide ions play a critical role in dictating the final structure and reactivity of metal-templated Schiff-base macrocycles.
- Transmetalation processes are influenced by both metal ion identity and the nature of the halide counterion.
- The study highlights the potential for controlling macrocyclic complex formation and transformation through judicious choice of metal ions and halide species.
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