Extending substrate sensing capabilities of zinc tris(2‐pyridylmethyl)amine‐based stereodynamic probe

Abstract

Tripodal metal complexes have been widely used for catalysis and more recently also for molecular recognition applications. Their ability in recognition and signal amplification of chiral substrates is because of the setup of the ligand around the metal in a propeller shape. Within this subject, we have recently reported tris(2-pyridylmethyl)amine-and triphenolamine-based complexes for the determination of the enantiomeric excess of various substrates.Herein, we show the versatility of the zinc tris(2-pyridylmethyl)amine-based stereodynamic probe by performing a detailed study of the imine formation process, by the extension of the sensing capabilities to other chiral compounds. A principal component analysis study of the system together with TD-DFT studies highlights the molecular origin of the observed chiroptical properties.

Tripodal gold(i) polypyridyl complexes and their Cu+and Zn2+heterometallic derivatives. Effects on luminescence

“…The emission spectra of the solids are also an evidence of the correct formation of the zinc and copper heterometallic complexes. The large Stokes' shift is in agreement with phosphorescence emission with a metal-perturbed intraligand transition probably mixed with 3 MMLCT transitions, based on the literature. [9,18,25] It can be observed a gradual red shift in the emission wavelength in the order Au(I) complex -Au(I)/Zn(II) -Au(I)/CuCl -Au(I)/Cu(BF 4 ) as shown in the Figure 4 and Table 3.…”

“…530 nm both in DMSO/water mixtures (Figure S18) and in acetonitrile (Figure 1 interactions (in agreement with intra-and/or intermolecular aggregates). Thus, the emission has being assigned to triplet metal-perturbed intraligand -*(C≡C) transitions or 3 MMLCT transitions according to literature. 10,18,21,[25][26][27][28][29] The large Stokes shift and the increased emission intensity upon deoxygenation of the samples support the phosphorescence assignment.…”

“…Tris(2-pyridylmethyl)amine (TPA) which possesses four nitrogen atoms able for the ligation of a wide variety of metal ions, and its derivatives are a family of versatile ligands that has been extensively studied. [1] The mobility of its pyridine arms allows TPA to accommodate metal centers with different coordination geometries and electronic structures [2] with a wide variety of different application including optoelectronics, sensing [3][4][5][6] or catalysis [7,8] among others. The additional introduction of terminal alkynyl moieties allows the coordination with d 10 coinage-metals, such as gold(I), [9] that are very well known to favor the coordination by the establishment of metallophilic contacts.…”

Circular Dichroism Sensing: Strategies and Applications

“…Because the sign of the generated CD curves is causally linked to the chirality of the analyte it reveals its absolute configuration. Quantitative ee analysis is also possible and has been demonstrated numerous times with a very broad range of chiral compounds by Anslyn, [34][35][36][37][38][39][40][41][42][43] Nau and Biedermann, [44,45] Jiang, [46][47][48][49] Zonta, [50][51][52][53][54][55] Wolf [56][57][58][59][60][61][62][63][64][65] and through collaborative efforts from Chin, Hong and Kim [66][67][68] as well as Baik, Yoon and Kim. [69] These and several other laboratories [70][71][72][73][74][75][76] have developed assays that make use of the intensity of the induced CD amplitudes which is readily correlated to the ee of the analyte with the help of a calibration curve.…”

Mixed Multimetallic tris(2‐pyridylmethyl)amine Based Complexes: Synthesis and Chiroptical Properties

“…Recently, we have been working in the application of tris(2‐pyridylmethyl)amine ( TPMA ) [18] metal complexes both in catalysis [19–21] and supramolecular chemistry [22–25] . In particular, we exploited the sensor capabilities of a series of TPMA based molecular architectures in the determination of the enantiomeric excess of chiral molecules, using Circular Dichroism (CD), [26–31] Vibrational Circular Dichroism (VCD), [32] and Circular Polarised Luminescence (CPL) [30] . In a typical experiment, mixing a modified TPMA zinc complex with one equivalent of the desired amino acid and half equivalent of zinc perchlorate resulted in the almost exclusive formation of a crystalline solid, corresponding to the trinuclear architecture 3‐ZnZnZn (Scheme 1).…”