Abstract
The coordination of f-block cations with Schiff base oligopyrrolic macrocycles is discussed. Analysis of the mesophase of a uranyl 2,5-diformylpyrrole-derived expanded porphyrin complex through temperature-dependent X-ray diffraction (XRD) methods has provided evidence for liquid-crystalline properties, and for molecular stacking into columns, arranged in a 2D hexagonal lattice. In separate studies, UV-vis spectral analysis has indicated the formation of three new f-block oligopyrrolic complexes. Addition of neptunyl ([NpO2]2+) or plutonyl ([PuO2]2+) chloride salts to the free base of a dipyrromethane-derived Schiff base macrocycle induces an immediate spectral change, namely the growth of a Q-like band at 630 nm. Such changes in the absorption spectra cause a dramatic color change from pale yellow to blue. It is postulated that oxidation of this macrocycle, stimulated by reduction of the metal center, leads to the observed spectral changes. An immediate visible and spectral change is also observed with the reaction of lutetium silylamide (Lu[N(Si(CH3)3)2]3), with a different, tetrapyrrole-containing Schiff base macrocycle. In this case, the formation of a complex with 1:1 metal-to-ligand binding stoichiometry is further supported by MALDI-TOF mass spectrometry.
Original language | English |
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Pages (from-to) | 171-177 |
Number of pages | 7 |
Journal | Journal of Alloys and Compounds |
Volume | 418 |
Issue number | 1-2 |
DOIs | |
State | Published - Jul 20 2006 |
Externally published | Yes |
Scopus Subject Areas
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry
Keywords
- Chemical synthesis
- Liquid crystals
- X-ray diffraction