these Cu(II) complexes were synthesized. The fluorescence of [Cu(I/II)(qdeta)]+/2+ and [Cu(I/II)(bpqa)]+/2+ in aqueoussolution was characterized; [Cu(I)(qdeta)]+ and [Cu(I)(bpqa)]+ were found to fluoresce in aqueoussolution, whereas the fluorescence of [Cu(II)(qdeta)]2+ and [Cu(II)(bpqa)]2+ was almost completely quenched. The chelation enhanced fluorescence effect was observed for both [Cu(I)(qdeta)]+
A series of isomorphic 3D layered rareearth hydroxide (LREH) frameworks RE3(OH)7(1,5-NDS) (RE = Y (1), Gd (2), Er (3), Yb (4); 1,5-NDS = 1,5-naphthalenedisulfonate) has been synthesized under hydrothermal conditions. The crystal structures, thermal stabilities, photoluminescence, and magnetic properties of these compounds have been investigated. The results demonstrate that the compounds are highly
Under hydrothermal conditions, reaction of Cu(II)/Cd(II) salts with 1,5-naphthalenedisulfonate (1,5-NDS) and 4,5-diazafluoren-9-one (dafo) afforded [Cu(dafo)(2)(1,5-NDS)](n) (1) and [Cd(dafo)(2)(1,5-NDS)](n) (2), respectively. The compounds were characterized by elemental analysis, IR, PXRD, TG-DSC, and single-crystal X-ray diffraction. Both 1 and 2, which are the first M(II)-1,5-NDS-dafo systems, exhibit 3-D supramolecular structures generated by 1-D chains via C-HO hydrogen bonds and - interactions. Solid-state photoluminescence properties of both 1 and 2 were investigated with emission bands at 426-496nm ((ex)=280, 270nm for 1 and 2, respectively).
Syntheses, structures, and photoluminescence properties of Zn(II)/Cd(II) supramolecular architectures based on 1,5-naphthalenedisulfonate and 1,10-phenanthroline ligands
Two new supramolecular transition metal compounds, [Zn(phen)(2)(1,5-NDS)(H2O)] and [Cd(phen)(2)(1,5-NDS)](n) (1,5-NDS = 1,5-naphthalenedisulfonate, phen = 1,10-phenanthroline), were obtained under hydrothermal/solvothermal conditions and structurally characterized by elemental analysis, IR, PXRD, TG-DSC, and single-crystal X-ray determination. They represent the first examples of Zn(II)/Cd(II) supramolecular compounds based on the 1,5-NDS/phen system. The Zn compound exhibits a 3D supramolecular structure via hydrogen bond (O-Ha <-O and C-Ha <-O) and pi-pi interactions. The Cd compound is a 3D supramolecular framework generated by 1D coordinated chains through a hydrogen bond (C-Ha <-O) and pi-pi interactions. In addition, photoluminescence properties for both have been discussed. [Zn(phen)(2)(1,5-NDS)(H2O)] shows an emission peak at 420 nm (lambda (ex) = 342 nm), and [Cd(phen)(2)(1,5-NDS)] (n) displays a strong emission peak at 388 nm with a shoulder peak at 369 nm (lambda (ex) = 332 nm)..
Cage‐To‐Cage Transformations in Self‐Assembled Coordination Cages Using “Acid/Base” or “Guest Binding‐Induced Strain” as Stimuli
Controlling supramolecular systems between different functional forms by utilizing acids/bases as stimuli is a formidable challenge, especially where labile coordination bonds are involved. A pair of acid/base responsive, interconvertible 1,5‐enedione/pyrylium based Pd2L4‐type cages are prepared that exhibit differential guest binding abilities towards disulfonates of varied sizes. A three‐state switch has been achieved, where (i) a weakly coordinating base induced cage‐to‐cage transformation in the first step, (ii) a strongly coordinating base triggered cage disassembly as the second step, and (iii) the third step shows acid(strong) promoted generation of initial cage, thereby completing the cycle. To our surprise, binding of a specific disulfonate guest facilitated cage‐to‐cage transformations by inducing strain on the cage assembly thereby opening the labile pyrylium rings of the cage. Through competitive guest binding study, we demonstrated superior guest binding capability of octa‐cationic pyrylium‐based cage over a similar‐sized tetra‐cationic cage. These results provide a reliable approach to reversibly modulate the guest binding properties of acid/base‐responsive self‐assembled coordination cages.