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Gallo E, Bellucci L, Carlotto S, Bottaro G, Babetto L, Giordano L, Marchetti F, Samaritani S, Armelao L, Labella L. Aluminium 8-Hydroxyquinolinate N-Oxide as a Precursor to Heterometallic Aluminium-Lanthanide Complexes. Molecules 2024; 29:451. [PMID: 38257364 PMCID: PMC10821320 DOI: 10.3390/molecules29020451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 01/11/2024] [Accepted: 01/12/2024] [Indexed: 01/24/2024] Open
Abstract
A reaction in anhydrous toluene between the formally unsaturated fragment [Ln(hfac)3] (Ln3+ = Eu3+, Gd3+ and Er3+; Hhfac = hexafluoroacetylacetone) and [Al(qNO)3] (HqNO = 8-hydroxyquinoline N-oxide), here prepared for the first time from [Al(OtBu)3] and HqNO, affords the dinuclear heterometallic compounds [Ln(hfac)3Al(qNO)3] (Ln3+ = Eu3+, Gd3+ and Er3+) in high yields. The molecular structures of these new compounds revealed a dinuclear species with three phenolic oxygen atoms bridging the two metal atoms. While the europium and gadolinium complexes show the coordination number (CN) 9 for the lanthanide centre, in the complex featuring the smaller erbium ion, only two oxygens bridge the two metal atoms for a resulting CN of 8. The reaction of [Eu(hfac)3] with [Alq3] (Hq = 8-hydroxyquinoline) in the same conditions yields a heterometallic product of composition [Eu(hfac)3Alq3]. A recrystallization attempt from hot heptane in air produced single crystals of two different morphologies and compositions: [Eu2(hfac)6Al2q4(OH)2] and [Eu2(hfac)6(µ-Hq)2]. The latter compound can be directly prepared from [Eu(hfac)3] and Hq at room temperature. Quantum mechanical calculations confirm (i) the higher stability of [Eu(hfac)3Al(qNO)3] vs. the corresponding [Eu(hfac)3Alq3] and (ii) the preference of the Er complexes for the CN 8, justifying the different behaviour in terms of the Lewis acidity of the metal centre.
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Affiliation(s)
- Elisa Gallo
- Dipartimento di Chimica e Chimica Industriale and CIRCC, Università di Pisa, via Giuseppe Moruzzi 13, I-56124 Pisa, Italy (L.G.)
| | - Luca Bellucci
- Dipartimento di Chimica e Chimica Industriale and CIRCC, Università di Pisa, via Giuseppe Moruzzi 13, I-56124 Pisa, Italy (L.G.)
- ICMATE-CNR and INSTM, Presso Dipartimento di Scienze Chimiche, Università di Padova, via Marzolo 1, I-35131 Padova, Italy; (S.C.)
| | - Silvia Carlotto
- ICMATE-CNR and INSTM, Presso Dipartimento di Scienze Chimiche, Università di Padova, via Marzolo 1, I-35131 Padova, Italy; (S.C.)
- Dipartimento di Scienze Chimiche and INSTM, Università di Padova, via Marzolo 1, I-35131 Padova, Italy
| | - Gregorio Bottaro
- ICMATE-CNR and INSTM, Presso Dipartimento di Scienze Chimiche, Università di Padova, via Marzolo 1, I-35131 Padova, Italy; (S.C.)
| | - Luca Babetto
- Dipartimento di Scienze Chimiche and INSTM, Università di Padova, via Marzolo 1, I-35131 Padova, Italy
| | - Luca Giordano
- Dipartimento di Chimica e Chimica Industriale and CIRCC, Università di Pisa, via Giuseppe Moruzzi 13, I-56124 Pisa, Italy (L.G.)
| | - Fabio Marchetti
- Dipartimento di Chimica e Chimica Industriale and CIRCC, Università di Pisa, via Giuseppe Moruzzi 13, I-56124 Pisa, Italy (L.G.)
| | - Simona Samaritani
- Dipartimento di Chimica e Chimica Industriale and CIRCC, Università di Pisa, via Giuseppe Moruzzi 13, I-56124 Pisa, Italy (L.G.)
| | - Lidia Armelao
- Dipartimento di Scienze Chimiche and INSTM, Università di Padova, via Marzolo 1, I-35131 Padova, Italy
- Dipartimento di Scienze Chimiche e Tecnologie dei Materiali (DSCTM), Consiglio Nazionale Delle Ricerche, Piazzale A. Moro 7, I-00185 Roma, Italy
| | - Luca Labella
- Dipartimento di Chimica e Chimica Industriale and CIRCC, Università di Pisa, via Giuseppe Moruzzi 13, I-56124 Pisa, Italy (L.G.)
- ICMATE-CNR and INSTM, Presso Dipartimento di Scienze Chimiche, Università di Padova, via Marzolo 1, I-35131 Padova, Italy; (S.C.)
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Bellucci L, Carlotto S, Bottaro G, Babetto L, Labella L, Gallo E, Marchetti F, Samaritani S, Armelao L. Competing excitation paths in luminescent heterobimetallic Ln-Al complexes: Unraveling interactions via experimental and theoretical investigations. iScience 2023; 26:106614. [PMID: 37250321 PMCID: PMC10214411 DOI: 10.1016/j.isci.2023.106614] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/15/2023] [Accepted: 03/31/2023] [Indexed: 05/31/2023] Open
Abstract
The interest for heterometallic lanthanide-d or-p metal (Ln-M) complexes is growing because of a potential cooperative or synergistic effect related to the proximity of two different metals in the same molecular architecture affording special tunable physical properties. To exploit the potentiality of Ln-M complexes, suitable synthetic approaches, and the in-depth understanding of the effect of each building block on their properties are mandatory. Here, we report the study on a family of heterometallic luminescent complexes [Ln(hfac)3Al(L)3], Ln= Eu3+ and Tb3+. Using different L ligands, we investigated the effect of the steric and electronic properties of the Al(L)3 fragment, highlighting the general validity of the employed synthetic route. A marked difference in the light emission of [Eu(hfac)3Al(L)3] and [Tb(hfac)3Al(L)3] complexes has been observed. Thanks to photoluminescence experiments and Density Functional Theory calculations, Ln3+ emissions are explained with a model involving two non-interacting excitation paths through hfac or Al(L)3 ligands.
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Affiliation(s)
- Luca Bellucci
- CNR ICMATE and INSTM, Dipartimento di Scienze Chimiche, Università di Padova, via Marzolo 1, 35131 Padova, Italy
- Dipartimento di Chimica e Chimica Industriale and CIRCC, Università di Pisa, via Giuseppe Moruzzi 13, 56124 Pisa, Italy
| | - Silvia Carlotto
- CNR ICMATE and INSTM, Dipartimento di Scienze Chimiche, Università di Padova, via Marzolo 1, 35131 Padova, Italy
- Dipartimento di Scienze Chimiche and INSTM, Università di Padova, via Marzolo 1, 35131 Padova, Italy
| | - Gregorio Bottaro
- CNR ICMATE and INSTM, Dipartimento di Scienze Chimiche, Università di Padova, via Marzolo 1, 35131 Padova, Italy
| | - Luca Babetto
- Dipartimento di Scienze Chimiche and INSTM, Università di Padova, via Marzolo 1, 35131 Padova, Italy
| | - Luca Labella
- CNR ICMATE and INSTM, Dipartimento di Scienze Chimiche, Università di Padova, via Marzolo 1, 35131 Padova, Italy
- Dipartimento di Chimica e Chimica Industriale and CIRCC, Università di Pisa, via Giuseppe Moruzzi 13, 56124 Pisa, Italy
| | - Elisa Gallo
- Dipartimento di Chimica e Chimica Industriale and CIRCC, Università di Pisa, via Giuseppe Moruzzi 13, 56124 Pisa, Italy
| | - Fabio Marchetti
- Dipartimento di Chimica e Chimica Industriale and CIRCC, Università di Pisa, via Giuseppe Moruzzi 13, 56124 Pisa, Italy
| | - Simona Samaritani
- Dipartimento di Chimica e Chimica Industriale and CIRCC, Università di Pisa, via Giuseppe Moruzzi 13, 56124 Pisa, Italy
| | - Lidia Armelao
- Dipartimento di Scienze Chimiche and INSTM, Università di Padova, via Marzolo 1, 35131 Padova, Italy
- Dipartimento di Scienze Chimiche e Tecnologie dei Materiali (DSCTM) Consiglio Nazionale delle Ricerche Piazzale A. Moro 7, 00185 Roma, Italy
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Lyczko K, Rode JE, Dobrowolski JC. Chiral Lanthanide Complexes with l- and d-Alanine: An X-ray and Vibrational Circular Dichroism Study. Molecules 2020; 25:E2729. [PMID: 32545530 PMCID: PMC7357152 DOI: 10.3390/molecules25122729] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/09/2020] [Accepted: 06/10/2020] [Indexed: 01/17/2023] Open
Abstract
A whole series of [Ln(H2O)4(Ala)2]26+ dimeric cationic lanthanide complexes with both L- and D-alanine enantiomers was synthesized. The single-crystal X-ray diffraction at 100 and 292 K shows the formation of two types of dimers (I and II) in crystals. Between the dimer centers, the alanine molecules behave as bridging (μ2-O,O'-) and chelating bridging (μ2-O,O,O'-) ligands. The first type of bridge is present in dimers I, while both bridge forms can be observed in dimers II. The IR and vibrational circular dichroism (VCD) spectra of all L- and D-alanine complexes were registered in the 1750-1250 cm-1 range as KBr pellets. Despite all the studied complexes are exhibiting similar crystal structures, the spectra reveal correlations or trends with the Ln-O1 distances which exemplify the lanthanide contraction effect in the IR spectra. This is especially true for the positions and intensities of some IR bands. Unexpectedly, the ν(C=O) VCD bands are quite intense and their composed shapes reveal the inequivalence of the C=O vibrators in the unit cell which vary with the lanthanide. Unlike in the IR spectra, the ν(C=O) VCD band positions are only weakly correlated with the change of Ln and the VCD intensities at most show some trends. Nevertheless, this is the first observation of the lanthanide contraction effect in the VCD spectra. Generally, for the heavier lanthanides (Ln: Dy-Lu), the VCD band maxima are very close to each other and the mirror reflection of the band of two enantiomers is usually better than that of the lighter Lns. DFT calculations show that the higher the multiplicity the higher the stability of the system. Actually, the molecular geometry in crystals (at 100 K) is well predicted based on the highest-spin structures. Also, the simulated IR and VCD spectra strongly depend on the Ln electron configuration but the best overall agreement was reached for the Lu complex, which is the only system with a fully filled f-shell.
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Affiliation(s)
- Krzysztof Lyczko
- Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw, Poland; (J.E.R.); (J.C.D.)
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