Alkali Ion - Ce³⁺- DipicH₂System : Coordination Networks and Water Clusters.

Abstract

Heterometallic coordination polymers having the general formula [A3(H2O)nCe(dipic)3]⋅mH2O, where A denotes an alkali metal ion (Li–Cs), have been obtained by reacting an aqueous solution of Ce(NO3)3⋅6H2O with alkali hydroxides in presence of dipicH2. Ce(dipic)33– ion functions as a metallo‐ligand by linking the alkali ions. While the lightest alkali ion forms a 2D coordination network (1, n=6, m=3), all others form 3D networks (Na: 2, n=8, m=7; K: 3, n=9, m=3; Rb: 4 and 5, n=6, m=2; Cs: 6, n=6, m=3). The structure of compound 2 was inferred from the isomorphous Na−Gd compound (7) which formed better quality crystals. Remarkably, both Na and K networks are built around alkali ion‐water chains. In the case of the three lighter alkali ions, the lattice water molecules are assembled into water clusters: tetramer (Li); acyclic heptamer (Na); water tape (K). X‐ray powder diffraction studies show that the hydrated structures could be regenerated by exposure of the dehydrated samples to moisture in the case of Li, Na and K, but not for Rb and Cs.

Crystal structures of two SmIII complexes with dipicolinate [DPA]2− ligands: comparison of luminescent properties of products obtained at different pH values

“…More details of this method are described in the supporting information. Na 3 [Sm(DPA) 3 ]Á14H 2 O was found to be best described as having the shape of a tricapped trigonal prism (TTP), with ideal = 1.16, which is in good agreement with what has been reported for other isostructural Ln III complexes (Albertsson, 1970(Albertsson, , 1972Hojnik et al, 2015;Mondry & Starynowicz, 1995;Tancrez et al, 2005;Elahi & Rajasekharan, 2016). The donor set in [Sm(DPA)(HDPA)(H 2 O) 2 ]Á4H 2 O is less symmetric compared to Na 3 [Sm(DPA) 3 ]Á14H 2 O, consisting of two nitrogen atoms and seven oxygen atoms.…”

“…compounds previously reported for La III , Ce III , Pr III , Nd III , Sm III , Eu III , Gd III , Tb III , Dy III , Ho III , Yb III , and Lu III (Albertsson, 1970;Hojnik et al, 2015;Albertsson, 1972;Albertsson et al, 1972;Mondry & Starynowicz, 1995;Tancrez et al, 2005;Elahi & Rajasekharan, 2016). Crystal data of Na 3 [Sm(DPA) 3 ]Á14H 2 O have been deposited at the CCDC (CSD code SOPGOT; Hu et al, 1989); however, without atomic coordinates, which motivated us to reinvestigate the crystal structure.…”

Deciphering and quantifying linear light upconversion in molecular erbium complexes

“…the most simple triple helical Er( iii ) complex with rather long intramolecular Er···H distances of 5.37 Å, also failed in providing either downshifting or upconversion processes in the solid state 21. A careful look at the crystal structures of the latter complexes43 shows that interstitial water molecules accumulate along the threefold axis of the [Ln(2,6 dipicolinate) 3 ] 3– activators, thus leading to shorter intermolecular Er···H distances around 3.56 Å, an organization which appears to be incompatible with the detection of any radiative signals following excitation.…”

Contrasting impact of coordination polyhedra and site symmetry on the electronic energy levels in nine-coordinated Eu(iii) and Sm(iii) crystals structures determined from single crystal luminescence spectra

“…Cs 3 [Sm(DPA) 3 ]•9H 2 O was found to be isostructural to the Cs 3 [Ln(DPA) 3 ]•9H 2 O compounds, which has previously been reported for Ce 3+ , Eu 3+ , Tb 3+ , and Yb 3+ (CCDC entries FEMPUL, YOZRUA 1306070 1497223, HOYTEV 622323, and HOYTIZ 623104). 49,50,60 Fig. 2d illustrates the [DPA] 2− donor set that consists of three nitrogen atoms placed in the capping layer, and six oxygen atoms in the two trigonal layers in the assumed nine coordinated TTP coordination polyhedra.…”