Self-assembly of emissive supramolecular rosettes with increasing complexity using multitopic terpyridine ligands

Abstract

Coordination-driven self-assembly has emerged as a powerful bottom-up approach to construct various supramolecular architectures with increasing complexity and functionality. Tetraphenylethylene (TPE) has been incorporated into metallo-supramolecules to build luminescent materials based on aggregation-induced emission. We herein report three generations of ligands with full conjugation of TPE with 2,2′:6′,2″-terpyridine (TPY) to construct emissive materials. Due to the bulky size of TPY substituents, the intramolecular rotations of ligands are partially restricted even in dilute solution, thus leading to emission in both solution and aggregation states. Furthermore, TPE-TPY ligands are assembled with Cd (II) to introduce additional restriction of intramolecular rotation and immobilize fluorophores into rosette-like metallo-supramolecules ranging from generation 1-3 (G1−G3). More importantly, the fluorescent behavior of TPE-TPY ligands is preserved in these rosettes, which display tunable emissive properties with respect to different generations, particularly, pure white-light emission for G2.

Ddpd as Expanded Terpyridine: Dramatic Effects of Symmetry and Electronic Properties in First Row Transition Metal Complexes

“…At 263 K, this Jahn-Teller distortion is probably dynamic, as the difference between the short and long equatorial bonds (∆d sl = 0.028 Å) is less than that in [Cr(NCCH 3 ) 6 ][BPh 4 ] 2 at 110 K (Cr-N = 2.0655, 2.0918 and 2.4231 Å) [130]. The electronic and geometric situation is similar to that of the d 9 The neutral complex [Cr(tpy) 2 ] 0 is conveniently prepared from Cr(CO) 6 and tpy [27]. No heteroleptic intermediate complex Cr(CO) 3 (tpy) has been reported, probably due to the required meridional configuration of Cr(CO) 3 (tpy) with trans positioned CO ligands, in contrast to the stable fac-Cr(CO) 3 (py) 3 complex already prepared by Hieber [131,132].…”

“…Pincer-type [1,2] terpyridine ligands (2,2 :6 ,2 -terpyridine tpy; pincer ligands are tridentate, 6-electron donor ligands that enforce a meridional coordination geometry on the metal centre) and their manifold complexes [3] play a central role in key fields of coordination chemistry with important applications in supramolecular chemistry [4][5][6][7][8][9][10][11][12][13][14], spin-crossover (SCO) phenomena [15][16][17][18], homogeneous catalysis [19][20][21], biomedical applications [22], redox non-innocence [23][24][25][26][27] or photochemistry [6,7,28], to name just a few.…”

Tetraphenylethylene-Based Emissive Supramolecular Metallacages Assembled by Terpyridine Ligands

“…Currently, a series of discrete two-dimensional (2D) macrocycles, three-dimensional (3D) cages, and nanomaterials with well-defined sizes and shapes were constructed by coordination-driven self-assembly. [35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] In this field, Stang and co-workers 51 reported the first TPE-based supramolecular cage, which brought about the recent flourishing of AIE-active metalla-supramolecular cages with tunable properties. [52][53][54] Among most of these structures, the TPE moieties were either attached or embedded in the supramolecules, and their emissions still followed the classic AIE principle.…”

“…Accordingly, high fluorescent efficiency was mainly observed in their aggregate state, in which the rotations of the benzene rings were restricted effectively. 55 Nonetheless, in the solution state, as well as the isolated supramolecular cage scenario, these nonaggregate supramolecules were still nonemissive or weakly luminescent, 47,48,50,54,[56][57][58][59][60] which severely limited the application prospect of the TPE molecule.…”

A nano-cocktail of an NIR-II emissive fluorophore and organoplatinum(ii) metallacycle for efficient cancer imaging and therapy

“…[4][5][6][7][8][9] Meanwhile, Pt(II)-based SCCs demonstrate interesting photo-physical properties including the ability to emit in the visible spectrum, allowing the delivery and release of organoplatinum(II) to be monitored at the cellular level. 5,[10][11][12][13] Despite these excellent properties, the potential decomposition of organoplatinum(II)-based SCCs in the presence of amino acids (histidine, lysine, arginine etc.) is the major obstacle for successful in vivo applications.…”