Jump to main content
Jump to site search

Issue 44, 2017
Previous Article Next Article

Heteroleptic complexes via solubility control: examples of Cu(ii), Co(ii), Ni(ii) and Mn(ii) complexes based on the derivatives of terpyridine and hydroxyquinoline

Author affiliations

Abstract

We describe the construction of synthetically challenging heteroleptic complexes by capitalizing on the solubility properties of their corresponding favored homoleptic complexes. We demonstrate that the formation of a heteroleptic Cu2+ complex based on 2,2′:6′,2′′-terpyridine (Terpy) and 8-hydroxyquinoline (HQ) is not possible due to the insolubility of (HQ)2Cu2+. Replacing HQ with 8-hydroxy-2-quinolinecarbonitrile (HQCN) enabled the solubility of (HQCN)2Cu2+ in acetonitrile, leading to the formation of the heteroleptic complex Terpy(HQCN)Cu2+, TQCu. Applying these conditions to the synthesis of the corresponding heteroleptic Co2+ complex resulted in TerpyCo2+(acetate)2, which is insoluble in acetonitrile. Upon changing the solvent to methanol, the carbonitrile group of HQCN was converted to carboxyimidate HQOMe yielding a heteroleptic complex Terpy(HQOMe)Co2+, TQ′Co. Using this method, we also generated the heteroleptic complex TQ′Ni and the polynuclear heteroleptic complex Q′4Q′′2Mn4 (Q′′ = HQO2Me). Detailed analysis of the complexes included characterization by X-ray diffraction, EPR, UV-Vis, high resolution ESI MS, DFT calculations and electrochemistry. X-ray analysis of TQCu revealed distorted square pyramidal geometry, while TQ′Co and TQ′Ni exhibit distorted octahedral geometry, which includes metal coordination via the carboxyimidate nitrogen site. Interestingly, Q′4Q′′2Mn4 was found to contain a [MnII43-O)22-O)4N10]2+ core, which adopts a distorted octahedral geometry, and two types of HQ chelators. Thus, Q′4Q′′2Mn4 is also heteroleptic even though it does not contain a Terpy ligand. Solution studies revealed that while TQCu is stable in solution, TQ′Co and TQ′Ni go through ligand exchange and are partially converted to their corresponding homoleptic complexes. Based on these data we could propose a mechanism for the formation of TQ′Co and TQ′Ni and show that TQ′Co can be prepared directly from Terpy and HQOMe.

Graphical abstract: Heteroleptic complexes via solubility control: examples of Cu(ii), Co(ii), Ni(ii) and Mn(ii) complexes based on the derivatives of terpyridine and hydroxyquinoline

Back to tab navigation

Supplementary files

Article information


Submitted
12 Sep 2017
Accepted
09 Oct 2017
First published
09 Oct 2017

Dalton Trans., 2017,46, 15330-15339
Article type
Paper

Heteroleptic complexes via solubility control: examples of Cu(II), Co(II), Ni(II) and Mn(II) complexes based on the derivatives of terpyridine and hydroxyquinoline

M. Baskin, N. Fridman, M. Kosa and G. Maayan, Dalton Trans., 2017, 46, 15330 DOI: 10.1039/C7DT03387G

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.


Social activity

Search articles by author

Spotlight

Advertisements