A New 3D Pb(II) Inorganic–Organic Hybrid Framework Based on Terephthalate Acid with the Inorganic Pb–O–Pb Connectivity

Site-selective Eu(iii) spectroscopy of highly efficient luminescent mixed-metal Pb(ii)/Eu(iii) coordination polymers

“…Single-crystal XRD studies of Pb 0.90 Eu 0.10 -BDC For approximately an 10% inclusion of Eu 3+ (Pb 0.90 Eu 0.10 -BDC), we were able to obtain single-crystals large enough which allowed an unequivocally structural elucidation using singlecrystal XRD at low temperature. As expected, the unit cell parameters and space group match those previously reported for the pure Pb 2+ material, [24][25][26][27] showing that the threedimensional network remain essentially unaltered. However, during the renement stages, a charge problem arose: because of the inclusion of +3 charges at the sites of the +2 charges, and in the absence of voids capable of accommodate partiallyoccupied counter-ions to balance the crystal charge, the metallic center site has mandatorily to also be occupied by vacancies.…”

“…As previously described for the other structural determinations, [24][25][26][27] the M center appear 7-coordinated, {MO 7 }, with the overall coordination polyhedron being signicantly distorted due to the presence of a stereoactive lone pair of electrons belonging to the Pb 2+ metallic center. Indeed, considering the position of this lone pair of electrons as a possible coordination site, the overall coordination sphere resembles very much a highly distorted pentagonal bipyramid, with the M-O distances ranging between 2.483(4) and 2.775(4)Å.…”

“…XRD and PXRD studies The PXRD patterns show clearly that the mixed-metal Pb 1Àx Eu x -BDC (x ¼ 0.05 and 0.10) compounds are structurally similar to [Pb(BDC)] n , whose structure was originally reported by Tan et al 24 and later re-determined a handful of times. [25][26][27] This was unequivocally conrmed by Rietveld renement, Fig. S1 and S2 (ESI †).…”

“…36 The Rietveld renement for Pb 1Àx Eu x -BDC (x ¼ 0.05, 0.10, 0.25, 0.50) were performed with the GSAS/EXPGUI 37 soware using as starting premise the atomic coordinates of the previously reported [Pb(BDC)] n (ref. [24][25][26][27] and [Eu 2 (BDC) 3 (H 2 O) 4 ] 28,29 structures. The preferential orientation was corrected using the spherical harmonic model (tenth order) proposed by Jarvinen, 38 the peak prole was adjusted by the Thompson-Cox-Hastings function modied by Young and Desai (pV-TCHZ), 39,40 the surface roughness correction was rened by the Pitschke function and the background was tted by an eighth-degree shied Chebyshev polynomial function.…”

“…The Pb 1Àx Eu x -BDC (x ¼ 0.05, 0.10, 0.25, 0.50 and 1.00) materials were characterized by X-ray powder diffraction, single crystal X-ray diffraction and luminescence spectroscopy. Whereas for x ¼ 0.05 and 0.10 the Pb 1Àx Eu x -BDC compounds are structurally similar to [Pb(BDC)] n , [24][25][26][27] for x ¼ 0.50 the CP exhibits the structure of the [Eu 2 (BDC) 3 (H 2 O) 4 ] hydrated phase. 28,29 The Pb 0.75 Eu 0.25 -BDC compound displays a mixture of both crystalline phases with a intriguing high emission quantum yield (69 AE 7%).…”