Polymeric Zinc Ferrocenyl Sulfonate as a Molecular Aspirator for the Removal of Toxic Metal Ions

Abstract

A porous bilayered open coordination polymer [Zn(4,4'-bpy)(2)(FcphSO(3))(2)](n) (1; FcphSO(3)Na=m-ferrocenyl benzenesulfonate), has been assembled from Zn(NO(3))(2), m-ferrocenyl benzenesulfonate, and the bridging ligand 4,4'-bipyridine (4,4'-bpy). Ion-exchange induced products [Cd(0.6)Zn(0.4)(4,4'-bpy)(2)(FcphSO(3))(2)](n) (2), [Zn(0.75)Pb(0.25)(4,4'-bpy)(2)(FcphSO(3))(2)](n) (3), and [Cu(0.5)Zn(0.5)(4,4'-bpy)(2)(FcphSO(3))(2)](n) (4) could be obtained directly by suspending a big single crystal of 1 into concentrated solutions of Cd(NO(3))(2), Pb(NO(3))(2), and Cu(NO(3))(2), respectively. Most importantly, the big single crystal of 1 could be partly regenerated after immersion into concentrated aqueous solutions of Zn(NO(3))(2). On the other hand, powdered 1 could also be used as a metal ion adsorbent because of the well-defined pore size and pore shape. Ion exchange takes place along with the process of ion sorption. The big single crystal of 1 removes harmful metal ions by means of ion exchange, whereas powdered 1 removes toxic metal ions mainly through ion sorption. Also, compound 1 could be employed as a multi-ion analysis fluorescent probe to detect dangerous metal ions, such as Pb(2+), Cd(2+), Ag(+), and Cu(2+). The compounds described in this study may have potential applications in the design of new molecular devices.

Dynamic Equilibria in Solvent‐Mediated Anion, Cation and Ligand Exchange in Transition‐Metal Coordination Polymers: Solid‐State Transfer or Recrystallisation?

“…[35,36] Moreover, some single-crystal to single-crystal exchange processes have been reported. [25,37,38] Based upon these observations, a general view has formed that ion exchange processes in coordination polymers take place through a solidstate diffusion mechanism. [25,[29][30][31][32][33][34][35][36]39] Such a solid-state mechanism implies that ion exchange proceeds through the diffusion of free ions within channels of coordination polymer crystals or microcrystals.…”

“…[25,37,38] Based upon these observations, a general view has formed that ion exchange processes in coordination polymers take place through a solidstate diffusion mechanism. [25,[29][30][31][32][33][34][35][36]39] Such a solid-state mechanism implies that ion exchange proceeds through the diffusion of free ions within channels of coordination polymer crystals or microcrystals. [40,41] Recently, we have demonstrated [42,43] that ion exchange in Ag I polymers with heterocyclic ligands occurs through a solvent-mediated mechanism [44] and not through a solid-state process.…”

“…These materials have attracted a great deal of attention [1][2][3][4][5][6] not only because of their ability to form unusual structures [7] , but also due to their potential applications in physical and chemical adsorption, [8][9][10][11][12][13][14][15][16] ion exchange, [17][18][19] heterogeneous catalysis, [20][21] electronic and optical properties, [22] separation processes, [23][24][25] sensor technology, [26] and drug delivery. [27] Ion exchange, one of the most interesting properties of metal coordination polymers, has been extensively investigated, [17][18][19][28][29][30][31][32][33][34][35] and solvent-mediated ion-exchange reactions have been commonly assigned as "solid-state processes" even though often no unequivocal Providing that the solubility of the starting complex is sufficiently high, all the components of the coordination polymer, namely the anion, the cation and the ligand, can be exchanged on contact with a solution phase of a competing component.…”

Tunable Selectivity of Lanthanide Ion Exchange within a Coordination Polymer

“…8,9 In the latter case, the environment of the ion and the ligand should be different from that in a mononuclear complex. Consequently, it is expected that ion exchange within the framework of the CP entails a unique selectivity.…”

“…CPs show two types of ion-exchange phenomena: (i) exchange of extraframework ions (i.e., anions or cations as guests); [6][7][8] and (ii) exchange of central metal ions that are the part of the framework. 8,9 In the latter case, the environment of the ion and the ligand should be different from that in a mononuclear complex. Consequently, it is expected that ion exchange within the framework of the CP entails a unique selectivity.…”