In the PbIIX2/bp4mo (4,4′-bipyridine N-oxide) system, four coordination polymers (CPs) with the formulation of [PbX2(bp4mo)] are obtained. Compounds 1 and 2, in which X = Cl and Br, are polymorphs whose acentric structures are based on 2D CPs. On the contrary, the compound 3 (X = I) shows a close, but centrosymmetrical, structure compared with the ones of 1 and 2. Finally, the structure of compound 4, in which X = NO3–, is described by two-interpenetrated 3D networks. They all exhibit phosphorescence properties characterized by a broad emission band at around 600 nm, with lifetimes longer than tens of µs and quite high quantum yields that increase in the halide series from 6 % (1) to 27 % (3) and up to 34 % for 4. They also exhibit mechanochromic luminescence (MCL) properties: the grinding (g) of samples 1–4 involves nearly complete extinction of the luminescence, as well as a crystal to amorphous transition of the corresponding samples 1-g to 4-g. This phenomenon, which can be also considered a crystallization-enhanced emission process, is reversible either by heating, exposure to vapour (H2O, acetone) or by recrystallization in a few drops of acetone; however, it is accompanied by a loss of emission intensity. These compounds represent the first examples of MCL materials based on Pb2+.

Toma, O., Mercier, N., Allain, M., Meinardi, F., Botta, C. (2017). Lead(II) 4,4′-Bipyridine N-Oxide Coordination Polymers – Highly Phosphorescent Materials with Mechanochromic Luminescence Properties. EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, 2017(4), 844-850 [10.1002/ejic.201601230].

Lead(II) 4,4′-Bipyridine N-Oxide Coordination Polymers – Highly Phosphorescent Materials with Mechanochromic Luminescence Properties

MEINARDI, FRANCESCO
Penultimo
;
2017

Abstract

In the PbIIX2/bp4mo (4,4′-bipyridine N-oxide) system, four coordination polymers (CPs) with the formulation of [PbX2(bp4mo)] are obtained. Compounds 1 and 2, in which X = Cl and Br, are polymorphs whose acentric structures are based on 2D CPs. On the contrary, the compound 3 (X = I) shows a close, but centrosymmetrical, structure compared with the ones of 1 and 2. Finally, the structure of compound 4, in which X = NO3–, is described by two-interpenetrated 3D networks. They all exhibit phosphorescence properties characterized by a broad emission band at around 600 nm, with lifetimes longer than tens of µs and quite high quantum yields that increase in the halide series from 6 % (1) to 27 % (3) and up to 34 % for 4. They also exhibit mechanochromic luminescence (MCL) properties: the grinding (g) of samples 1–4 involves nearly complete extinction of the luminescence, as well as a crystal to amorphous transition of the corresponding samples 1-g to 4-g. This phenomenon, which can be also considered a crystallization-enhanced emission process, is reversible either by heating, exposure to vapour (H2O, acetone) or by recrystallization in a few drops of acetone; however, it is accompanied by a loss of emission intensity. These compounds represent the first examples of MCL materials based on Pb2+.
Articolo in rivista - Articolo scientifico
Coordination polymers; Lead; Luminescence; N,O ligands; Solid-state structures;
Mechanochromic Luminescence, Coordination Polymers
English
844
850
7
Toma, O., Mercier, N., Allain, M., Meinardi, F., Botta, C. (2017). Lead(II) 4,4′-Bipyridine N-Oxide Coordination Polymers – Highly Phosphorescent Materials with Mechanochromic Luminescence Properties. EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, 2017(4), 844-850 [10.1002/ejic.201601230].
Toma, O; Mercier, N; Allain, M; Meinardi, F; Botta, C
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/143792
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