The heterotopic divergent ligand N-oxide-4,4′-bipyridine (bipyMO) as directing-agent in the synthesis of oligo- or polynuclear heterometallic complexes

Dell’Amico, Daniela Belli; Ciattini, Samuele; Fioravanti, Lorenzo; Labella, Luca; Marchetti, Fabio; Mattei, Carlo Andrea; Samaritani, Simona

doi:10.1016/j.poly.2017.10.009

Cited by 8 publications

(14 citation statements)

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“… 36 − 38 Recently, we focused on lanthanide coordination chemistry with the heterotopic divergent N -oxide ligand 4,4′-bipyridine N -oxide (bipyMO). 39 − 41 The different affinities of 4f metal ions toward O- and N-donor ligands afford the synthesis of lanthanide dinuclear complexes with the composition [Ln 2 (β-diketonate) 6 (bipyMO) x ] ( x = 2, 3 depending on the β-diketonate) where the oxygen atom of bipyMO bridges two lanthanide ions and the nitrogen donor atom is not coordinated. 41 − 44 In this context, we developed a family (16 members) of homodinuclear Eu 3+ and Gd 3+ luminescent compounds to study the effect of the β-diketonato and N -oxide ligands on the thermometric properties of the complexes.…”

Section: Introductionmentioning

confidence: 99%

Composition–Thermometric Properties Correlations in Homodinuclear Eu³⁺ Luminescent Complexes

et al. 2020

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A family of homodinuclear Ln 3+ (Ln 3+ = Gd 3+ , Eu 3+ ) luminescent complexes with the general formula [Ln 2 (β-diketonato) 6 ( N -oxide) y ] has been developed to study the effect of the β-diketonato and N -oxide ligands on their thermometric properties. The investigated complexes are [Ln 2 (tta) 6 (pyrzMO) 2 ] (Ln = Eu ( 1 ·C 7 H 8 ), Gd ( 5 )), [Ln 2 (dbm) 6 (pyrzMO) 2 ] (Ln = Eu ( 2 ), Gd ( 6 )), [Ln 2 (bta) 6 (pyrzMO) 2 ] (Ln = Eu ( 3 ), Gd ( 7 )), [Ln 2 (hfac) 6 (pyrzMO) 3 ] (Ln = Eu ( 4 ), Gd ( 8 )) (pyrzMO = pyrazine N -oxide, Htta = thenoyltrifluoroacetone, Hdbm = dibenzoylmethane, Hbta = benzoyltrifluoroacetone, Hhfac = hexafluoroacetylacetone, C 7 H 8 = toluene), and their 4,4′-bipyridine N -oxide (bipyMO) analogues. Europium complexes emit a bright red light under UV radiation at room temperature, whose intensity displays a strong temperature ( T ) dependence between 223 and 373 K. This remarkable variation is exploited to develop a series of luminescent thermometers by using the integrated intensity of the 5 D 0 → 7 F 2 europium transition as the thermometric parameter (Δ). The effect of different β-diketonato and N -oxide ligands is investigated with particular regard to the shape of thermometer calibration (Δ vs T ) and relative thermal sensitivity curves: i.e.. the change in Δ per degree of temperature variation usually indicated as S r (% K –1 ). The thermometric properties are determined by the presence of two nonradiative deactivation channels, back energy transfer (BEnT) from Eu 3+ to the ligand triplet levels and ligand to metal charge transfer (LMCT). In the complexes bearing tta and dbm ligands, whose triplet energy is ca. 20000 cm –1 , both deactivation channels are active in the same temperature range, and both contribute to determine the thermometric properties. Conversely, with bta and hfac ligands the response of the europium luminescence to temperature variation is ruled by LMCT channels since the high triplet energy (>2...

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Section: Introductionmentioning

confidence: 99%

Composition–Thermometric Properties Correlations in Homodinuclear Eu³⁺ Luminescent Complexes

et al. 2020

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“…These polymers are characterized by the presence of two different regularly alternated coordination sites, M*[N] 2 and M*[O] 2 , (M* is the complementary metal coordination sphere and [N] and [O] specify the donor atom of the connector). Heterometallic CPs have been prepared for 3d [M II ‐M′ II = Mn‐Cu] or for 3d–4f metal centres [Ln III = Eu, M II = Cu, Zn; Ln III = Dy, M II = Co] . In these heterometallic polymers the perfect alternation of the coordination sites (Cu*[N] 2 and Mn*[O] 2 or M*[N] 2 and Ln*[O] 2 ) showed the efficient discrimination operated by bipyMO.…”

Section: Introductionmentioning

confidence: 99%

“…In these species the uncoordinated site (O or N, respectively) is engaged in hydrogen bonding, usually with water . Nevertheless, in the mononuclear platinum(II) derivative [PtCl 2 (PPh 3 )(bipyMO)], the hypodentate N‐coordinated ligand does not show significant interactions of the O‐site with other groups and the complex was successfully used as a metallo‐ligand …”

Section: Introductionmentioning

confidence: 99%

“…With the intent to extend our synthetic studies, on the coordination chemistry of the bipyMO ligand, its reactivity of the bipyMO ligand towards oxophylic open metal sites, as in [Ln(β‐dik) 3 ], appeared quite attractive. In this paper we report the synthesis of Eu 2 (dbm) 6 (bipyMO) 2 1 , Tb 2 (dbm) 6 (bipyMO) 2 2 , Eu 2 (tta) 6 (bipyMO) 2 3 Eu 2 (hfac) 6 (bipyMO) 3 4 , Tb 2 (hfac) 6 (bipy>MO) 3 ( 5 ) (Hdbm = dibenzoylmethane, Htta = thenoyltrifluoroacetone, Hhfac = hexafluoroacetylacetone).…”

Section: Introductionmentioning

confidence: 99%

“…In the literature, a few complexes have been reported where the bipyMO ligand behaves as connector producing homometallic CPs with metal centres belonging to the p ‐block [Pb II ,[3a], [3d] Bi III[3c] ] as well as to the d‐block [M II = Mn, Co, Cu and Zn] . These polymers are characterized by the presence of two different regularly alternated coordination sites, M*[N] 2 and M*[O] 2 , (M* is the complementary metal coordination sphere and [N] and [O] specify the donor atom of the connector).…”

Section: Introductionmentioning

confidence: 99%

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Homodinuclear Lanthanide Complexes with the Divergent Heterotopic 4,4′‐Bipyridine N‐Oxide (bipyMO) Ligand

et al. 2018

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The synthesis of dinuclear molecular complexes [Eu2(dbm)6(bipyMO)2], 1, [Tb2(dbm)6(bipyMO)2], 2, [Eu2(tta)6(bipyMO)2], 3 [Eu2(hfac)6(bipyMO)3], 4, [Tb2(hfac)6(bipyMO)3], 5 is here reported (bipyMO = 4,4′‐bipyridine N‐oxide, Hdbm = dibenzoylmethane, Htta = thenoyltrifluoroacetone, Hhfac = hexafluoroacetylacetone). The products were obtained in mild conditions and with high yields reacting anhydrous lanthanide β‐diketonates and bipyMO in 1:1 or 1.5 molar ratio in toluene. X‐ray single crystal studies on 2, 3, 4 showed that the heterotopic ligands are hypodentate, bridging the two lanthanide centres exclusively through the oxygen atom. Photoluminescence studies show bright red emissions from europium derivatives with absolute quantum yields up to 44 %.

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Size Selectivity in Heterolanthanide Molecular Complexes with a Ditopic Ligand

Bellucci

Fioravanti

Armelao

et al. 2022

Chemistry A European J

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The similar reactivity of lanthanides generally leads to statistically populated polynuclear complexes, making the rational design of ordered hetero‐lanthanide compounds extremely challenging. Here we report on the site selectivity in hetero‐lanthanide tetranuclear complexes afforded by the relatively simple ditopic pyterpyNO ligand (4’‐(4‐pyridil)‐2,2’:6’,2”‐terpyridine N‐oxide). The sequential room temperature reaction of RE2(tta)6(pyterpyNO)2 (where RE=Y, (1); Eu, (2), Dy, (3) Htta=2‐thenoyltrifluoroacetone) with La(tta)3dme (dme=dimethoxyethane) yielded Y2La2(tta)12(pyterpyNO)2 (4), Dy2La2(tta)12(pyterpyNO)2 (5) and Eu2La2(tta)12(pyterpyNO)2 (6). Single crystals X‐ray diffraction studies showed that 4, 5 and 6 are isostructural, featuring a tetranuclear structure with two different metal coordination sites with coordination numbers 8 (CN8) and 9 (CN9). The two smaller cations are mainly bridged by the O‐donor atoms of the NO groups of two pyterpyNO ligands (CN8), while the larger lanthanum centres are bound by a terpyridine unit (CN9). Size selectivity has been studied with structural and magnetic studies in the solid state and through 19F NMR and photoluminescence studies in solution, showing a direct dependence on the difference of ionic radii of the ions and yielding a 91 % selectivity for 4. Furthermore, 19F NMR, X‐ray and PL studies pointed out that the nature of the product is independent from the synthetic route for compound Eu2Y2(tta)12(pyterpyNO)2 (7), keeping the ion selectivity also for a self‐assembly reaction. Unexpectedly, these studies have evidenced that selectivity is not exclusively governed by electrostatic interactions related to size dimensions.

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The heterotopic divergent ligand N-oxide-4,4′-bipyridine (bipyMO) as directing-agent in the synthesis of oligo- or polynuclear heterometallic complexes

Cited by 8 publications

References 30 publications

Composition–Thermometric Properties Correlations in Homodinuclear Eu³⁺ Luminescent Complexes

Composition–Thermometric Properties Correlations in Homodinuclear Eu³⁺ Luminescent Complexes

Homodinuclear Lanthanide Complexes with the Divergent Heterotopic 4,4′‐Bipyridine N‐Oxide (bipyMO) Ligand

Size Selectivity in Heterolanthanide Molecular Complexes with a Ditopic Ligand

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The heterotopic divergent ligand N-oxide-4,4′-bipyridine (bipyMO) as directing-agent in the synthesis of oligo- or polynuclear heterometallic complexes

Cited by 8 publications

References 30 publications

Composition–Thermometric Properties Correlations in Homodinuclear Eu3+ Luminescent Complexes

Composition–Thermometric Properties Correlations in Homodinuclear Eu3+ Luminescent Complexes

Homodinuclear Lanthanide Complexes with the Divergent Heterotopic 4,4′‐Bipyridine N‐Oxide (bipyMO) Ligand

Size Selectivity in Heterolanthanide Molecular Complexes with a Ditopic Ligand

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Composition–Thermometric Properties Correlations in Homodinuclear Eu³⁺ Luminescent Complexes

Composition–Thermometric Properties Correlations in Homodinuclear Eu³⁺ Luminescent Complexes