Fluorenyl Zinc Phosphonate Zn(H₂O)PO₃-C₁₃H₉·H₂O: Hybrid Columnar Structure with Strong C-H···π Interactions

Abstract

A new zinc phosphonate Zn(H2O)PO3–C13H9·H2O with a columnar structure was synthesized in hydrothermal conditions. This compound crystallizes in space group P21/c [a = 15.832(4) Å, b = 5.1915(10) Å, c = 17.519(4) Å and β = 114.479(6)°]. Its inorganic framework consists of isolated chains of corner‐sharing ZnO3(H2O) and PO3C tetrahedra. These chains are linked to fluorene cycles, forming hybrid columns, interconnected through C–H···π bonds. The photoluminescence properties of this hybrid material show that its emission bands are red shifted with respect to those of the mother phosphonic acid. This effect is explained on the basis of the structural constraints imposed by the inorganic Zn‐phosphonate chains.

Manganese Fluorene Phosphonates: Formation of Isolated Chains

“…The organic ligands form layers parallel to (010) in Figure 1a, but the orientation of the dimethyl fluorene ligands within these layers in Figure 1c is different from that generally observed in other layered or chain manganese-based phosphonates: they show a cross-like configuration characterized by an angle close to 90 • (88.316 • ) between two successive ligands. However such type of orientation was reported in other metal-phosphonate materials [26,30]…”

“…This rigidity associated with the presence of additional functionalities (e.g., carboxylic acid) influenced the structure of the final hybrid materials [25]. More recently, we and others [26][27][28] explored fluorene as a new rigid aromatic backbone for the synthesis of hybrid structures via hydrothermal synthesis [29,30] or by intercalation in layered inorganic materials [5]. In the series of manganese-phosphonate hybrids we noticed that only few structures that incorporate non-functionalized phosphonic acid were reported.…”

Layered Simple Hydroxides Functionalized by Fluorene‐Phosphonic Acids: Synthesis, Interface Theoretical Insights, and Magnetoelectric Effect

“…[32,33] Phosphonic acids, due to their coordination properties, are widely employed to prepare crystalline hybrid materials [34] that are studied for their porosity, [35,36] ionic conduction, [37,38] magnetic, [39,40] or fluorescent [41,42] properties or for their bactericidal effects. [49,50] In this paper, we extend the use of fluorene-based compounds proposing novel mono-and diphosphonic acids, with various alkyl chains in position 9 of the fluorene unit (H, CH 3 or (CH 2 ) 7 CH 3 ) (Scheme 1), to foster, so far unexplored, magnetoelectric phenomena into Cu and Co layered simple hydroxides. [45] The rigidity results from a direct connection of the phosphonic acid on an aromatic [46] or heteroaromatic ring [47] acting as a rigid molecular platform.…”

“…In this respect, fluorene stands as an interesting rigid platform in which the presence of the five-membered ring breaks the symmetry of the compound. [49,50] In this paper, we extend the use of fluorene-based compounds proposing novel mono-and diphosphonic acids, with various alkyl chains in position 9 of the fluorene unit (H, CH 3 or (CH 2 ) 7 CH 3 ) (Scheme 1), to foster, so far unexplored, magnetoelectric phenomena into Cu and Co layered simple hydroxides. We address this challenge discussing in the following the synthesis, characterization, structural modeling, and magnetic and dielectric properties of new layered hybrid compounds, which will be referred to as A⊂M, where A is the mono-or diphosphonic acid fluorene and M denotes Co or Cu hydroxide layers.…”