Metal ions as external stimuli in stereoselective self-sorting of koneramines and thiokoneramines12. (26th September 2017)

• Record Type: Journal Article
• Authors: Raje, Sakthi; Mani, Kalaikodikumaran; MinnathParsutkar, Mahesh; Angamuthu, Raja
• Is Part Of: New journal of chemistry. Volume 41:Number 20(2017)
• Page Start: 12303
• Page End: 12308
• Publication Date: 2017-09-26
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c7nj01941f
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : Stereoselective self-sorting of koneramines and thiokoneramines, which are N3 ligands, evolved from the system of pyridine-2-carboxaldehyde, mono- N -substituted ethylenediamine, primary alcohol or thiol, is observed when metal ions such as Ni(ii ), Cu(ii ), Zn(ii ) and Cd(ii ) are added as external stimuli to isolate the emergent molecule. Abstract : Stereoselective self-sorting of hemiaminal ethers (koneramines) and hemiaminal thioethers (thiokoneramines), which are N3 ligands, evolved from the system of pyridine-2-carboxaldehyde, mono- N -substituted ethylenediamine, primary alcohol or thiol, is observed when metal ions such as nickel(ii ), copper(ii ), zinc(ii ) and cadmium(ii ) are added as external stimuli to isolate the emergent molecule. Interestingly, copper(ii ) and zinc(ii ) ions are found to specifically coordinate with syn -hemiaminal ether or anti -hemiaminal thioether equatorially, while nickel(ii ) and cadmium(ii ) ions coordinate specifically with anti -hemiaminal ether facially or anti -hemiaminal thioether equatorially. Another system of pyridine-2-carboxaldehyde, N -phenylethylenediamine, methanol, copper(ii ) and cadmium(ii ) shows a beautiful example of emergent phenomena, where anti -cadmium complex precipitates out cleanly from the system while syn -copper(ii ) complexes stay in the solution, whereas the same system yields only syn -copper(ii ) complex when the amount of metal ions is doubled. Interestingly, nickel(ii ) is the emergent complex when Ni(ii ) and Cd(ii ) are used, while copper(ii ) is the emergent complex when Ni(ii ) and Cu(ii ) are used. Amazingly, copper(ii ) is the sole emergent complex when a mixture of Ni(ii ), Cu(ii ), Cd(ii ) and Zn(ii ) is used. Only anti forms of thiokoneramine are found to coordinate equatorially with Ni(ii ), Cu(ii ), Cd(ii ) or Zn(ii ) when the stereoselective self-sorting is performed in ethanethiol. This stereoselective self-sorting process has been substantiated by the analysis of isolated molecules with analytical techniques such as electrospray mass ionisation spectrometry, nuclear magnetic resonance spectroscopy and single crystal X-ray diffraction analysis.