
You have already added 0 works in your ORCID record related to the merged Research product.
You have already added 0 works in your ORCID record related to the merged Research product.
<script type="text/javascript">
<!--
document.write('<div id="oa_widget"></div>');
document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=undefined&type=result"></script>');
-->
</script>
Phthalocyanine as a Chemically Inert, Redox-Active Ligand: Structural and Electronic Properties of a Nb(IV)-Oxo Complex Incorporating a Highly Reduced Phthalocyanine(4−) Anion

doi: 10.1021/ic902409n
pmid: 20225871
Phthalocyanine as a Chemically Inert, Redox-Active Ligand: Structural and Electronic Properties of a Nb(IV)-Oxo Complex Incorporating a Highly Reduced Phthalocyanine(4−) Anion
This report describes the reduction of a niobium(V) phthalocyanine complex and investigation of the electronic structure of the resulting products. The reduction of PcNbCl(3) (Pc = phthalocyanine dianion) with 5.5 equiv of potassium graphite in 1,2-dimethoxyethane (DME) resulted in the isolation of K(2)PcNbO.5DME (1a). Addition of 18-crown-6 to 1a gave [K(18-crown-6)](2)(mu-DME)PcNbO (1b). Both 1a and 1b were structurally characterized by single-crystal X-ray diffraction analysis. In both complexes, the niobium center adopts a square pyramidal geometry and is coordinated by four basal Pc nitrogen atoms and an apical oxo ligand. Notably, the Pc ligand in 1a is saddle-shaped, with significant bond length alternation, rather than flat with delocalized bonding. The production of ethylene during the reduction of PcNbCl(3), detected by gas chromatography/mass spectrometry (GC/MS), suggests that the oxo ligand likely results from double C-O bond activation of DME solvent. A combination of spectroscopic techniques and density functional theory (DFT) calculations were used to establish the electronic structure of 1a. The close correspondence of the electronic absorption spectrum of 1a to that of [PcZn](2-) with a di-reduced Pc(4-) ligand, indicates a similar electronic structure for the two complexes. Evaluation of the electronic transitions for 1a and [PcZn](2-) by time-dependent DFT calculations further suggests a similar electronic structure for both complexes, indicating that differences in symmetry between 1a and [PcZn](2-) do not significantly affect the nature of the electronic transitions. Electron paramagnetic resonance (EPR) spectroscopy of 1a in solution at room temperature gave a 10-line spectrum, while frozen-solution X- and Q-band EPR spectra are consistent with powder-pattern spectra defined by uniaxial g and (93)Nb hyperfine tensors: these imply the presence of a d(1) Nb(IV) metal center. EPR and electron nuclear double resonance spectroscopy suggests that the spin density in 1a is centered almost completely on the niobium, in agreement with the DFT calculations. These results illustrate the value of Pc as a chemically inert, redox-active ligand for stabilizing reactive metal centers.
- Simon Fraser University Canada
12 Research products, page 1 of 2
- 2006IsAmongTopNSimilarDocuments
- 2009IsAmongTopNSimilarDocuments
- 2011IsAmongTopNSimilarDocuments
- 2018IsAmongTopNSimilarDocuments
chevron_left - 1
- 2
chevron_right
citations This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).63 popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.Top 10% influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).Top 10% impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.Top 10%
