[Cr{tren(impy)3}](ClO4)3, where tren(impy)3 = N[CH2CH2N= C(H)(py)]3

McLachlan, Grant A.; Fallon, GD; Spiccia, Leone

doi:10.1107/s0108270195008870

Cited by 9 publications

(14 citation statements)

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“…Tren-based imines synthesized from the reaction of tris(2-aminoethyl)amine (tren) and an aldehyde are versatile ligands for transitional metals (Salehzadeh et al, 2006;McLachlan et al, 1996). Because of the simplicity, such imines are often converted directly into the corresponding amines, which are potential to bind a wide range of cations and anions (Bianchi et al, 1997;Kang et al, 2005).…”

Section: S1 Commentmentioning

confidence: 99%

Tris{2-[(3-thienyl)methylideneamino]ethyl}amine

et al. 2010

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The title compound, C21H24N4S3, is a tripodal Schiff base that was obtained from the reaction of tris(2-aminoethyl)amine (tren) and thiophene-3-carbaldehyde. The compound forms a cavity with approximate C3 symmetry. One of the thiophene units is disordered in a 0.764 (2):0.236 (2) ratio. In the crystal, the three thiophene ligands are involved in intramolecular C—H⋯π interactions and the molecules are connected by C—H⋯N interactions, forming hydrogen-bonded chains.

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Section: S1 Commentmentioning

confidence: 99%

Tris{2-[(3-thienyl)methylideneamino]ethyl}amine

et al. 2010

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“…Photochemical studies on a few chromium complexes ligated by multidentate amine ligands − or tethered bipyridines , have uncovered long-lived 2 E excited states, although it should be noted that all of these species are yellow and do not absorb strongly in the visible spectrum. However, a structural study for [Cr(tren(impy) 3 )](ClO 4 ) 3 reports a “wine red” color for crystals of the hexadentate ligand-containing Cr(III) complex salt, which contrasts with the typical bright yellow coloration of the hetero- and homoleptic tris(bidentate) polypyridyl complexes of Cr(III) . Thus, complexes featuring tripodal ligands could have enhanced absorption in the visible wavelengths coupled simultaneously with increased stability against ligand exchange in photoreduced species.…”

Section: Introductionmentioning

confidence: 99%

Syntheses and Photophysical Investigations of Cr(III) Hexadentate Iminopyridine Complexes and Their Tris(Bidentate) Analogues

et al. 2013

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We report the preparation, photophysical characterization, and computed excited state energies for a family of Cr(III) complexes based on iminopyridine (impy) Schiff base ligands: compounds 1 and 2 feature hexadentate ligands where tren (tris-(2-aminoethyl)amine) caps three impy groups; compounds 3 and 4 are tris(bidentate) analogues of 1 and 2; compounds 2 and 4 contain methyl ester substituents to alter ligand donation properties relative to 1 and 3, respectively. Cyclic voltammograms exhibit multiple reversible ligand-based reductions; the hexadentate and tris(bidentate) analogues have almost identical reduction potentials, and the addition of ester substituents shifts reduction potentials by +200 mV. The absorption spectra of the hexadentate complexes show improved absorption of visible light compared to the tris(bidentate) analogues. Over periods of several hours to days, the complexes undergo ligand-substitution-based decomposition in 1 M HCl((aq)) and acetonitrile. For freshly prepared sample solutions in CH(3)CN, time-resolved emission and transient absorption measurements for 4 show a doublet excited state with 17-19 μs lifetime at room temperature, while no emission or transient absorption signals from the doublet states are observed for the hexadentate analogue 2 under the same conditions. The electronic structure contributions to the differences in observed photophysical properties are compared by extensive computational analyses (UB3LYP MD-DFT and TD-DFT-NTO). These studies indicate that the presence of nonligated bridgehead nitrogen atoms for 1 and 2 significantly reduce excited state doublet, quartet, and sextet energies and change the character of the low lying doublet states in comparison to species that show population of doublet excited states.

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“…The Ag-N bond lengths to the imine nitrogen atoms (Ag1/ N2 2.2948 (13) A, Ag1/N3 2.3138(12) A, Ag1/N4 2.2946(13) A) are significantly shorter than the Ag1-N1 distance (2.4554 (12) A). The rigidity of Schiff-base linkages and the positioning of the aromatic end groups appear to inhibit further coordination of solvent or anion groups to the Ag(I) centre.…”

Section: X-ray Structures Of the Ag(i) Complexesmentioning

confidence: 93%

“…A subsequent study indicated the presence of similar pseudo-seven coordination in the corresponding Fe(II) complex. 12 Cr(III) 13 and Tc(II) 14 complexes of 3 have also been reported, with the smaller Cr(III) ion yielding a six-coordinate species, 13 while the larger Tc(II) ion shows a tendency for coordination of the apical tertiary amine. 14 More recent studies have expanded the range of complexes of 3 to include those of Cd(II) 15 and Ca(II).…”

Section: Introductionmentioning

confidence: 89%