Abstract
The pyrrolyldipyrrin motif is found in several naturally occurring prodigiosin pigments. The potential roles of the interactions of prodigiosins with transition metals and the properties of metal-bound pyrrolyldipyrrins, however, have been difficult to assess because of the very limited number of well-characterized stable complexes. Here, we show that the introduction of a meso-aryl substituent and an ethyl ester group during the sequential assembly of the three heterocycles affords a pyrrolyldipyrrin of enhanced coordinating abilities when compared to that of natural prodigiosins. UV-visible absorption studies indicate that this ligand promptly binds Zn(II) ions with 2:1 ligand-to-metal stoichiometry and Cu(II) ions with 1:1 stoichiometry. Notably, no addition of base is required for the formation of the resulting stable complexes. The crystal structures reveal that whereas the tetrahedral zinc center engages two nitrogen donors on each ligand, the pseudosquare planar copper complex features coordination of all three pyrrolic nitrogen atoms and employs the ester group as a neutral ligand. This first example of coordination of a redox-active transition metal within a fully conjugated pyrrolyldipyrrin framework was investigated spectroscopically by electron paramagnetic resonance to show that the 1:1 metal-to-ligand ratio found in the crystal structure is also maintained in solution.
Original language | English (US) |
---|---|
Pages (from-to) | 7518-7526 |
Number of pages | 9 |
Journal | Inorganic Chemistry |
Volume | 53 |
Issue number | 14 |
DOIs | |
State | Published - Jul 21 2014 |
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry
Fingerprint
Dive into the research topics of 'Prodigiosin analogue designed for metal coordination: Stable zinc and copper pyrrolyldipyrrins'. Together they form a unique fingerprint.Datasets
-
CCDC 994298: Experimental Crystal Structure Determination
Chang, T. M. (Creator), Sinharay, S. (Creator), Astashkin, A. V. (Creator) & Tomat, E. (Creator), Cambridge Crystallographic Data Centre, 2014
DOI: 10.5517/cc12cn47, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/cc12cn47&sid=DataCite
Dataset
-
CCDC 994299: Experimental Crystal Structure Determination
Chang, T. M. (Creator), Sinharay, S. (Creator), Astashkin, A. V. (Creator) & Tomat, E. (Creator), Cambridge Crystallographic Data Centre, 2014
DOI: 10.5517/cc12cn58, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/cc12cn58&sid=DataCite
Dataset