First Examples of Metal–Organic Frameworks with the Novel 3,3′-(1,2,4,5-Tetrazine-3,6-diyl)dibenzoic Spacer. Luminescence and Adsorption Properties

Abstract

We report the synthesis of a novel ligand, 3,3'-(1,2,4,5-tetrazine-3,6-diyl)dibenzoic acid (1). In this fragment, we have introduced two carboxylate groups with the aim of using this ligand as a linker to construct three-dimensional metal-organic frameworks (MOFs). We have been successful in the formation of zinc (2) and lanthanum (3) MOFs. The zinc compound is a two-dimensional structure, while the lanthanum material is a three-dimensional MOF with interesting channels. We include the luminescence and adsorption studies of these materials. Moreover, we have evaluated the in vitro toxicity of this novel ligand, concluding that it can be considered negligible.

An efficient and mild oxidant for the synthesis of s-tetrazines

“…1,2 In recent years, the bioorthogonal reactions of strained alkenes with s -tetrazines have served as tools for rapid bioorthogonal labeling, with applications that extend to cell biology, 3–5 nuclear medicine 6–8 and materials science. 9–12 In particular, the bioorthogonal reactions of s -tetrazines with trans- cyclooctene (TCO) derivatives have been shown to be exceptionally rapid, with rate constants in excess of k 2 = 10 6 M −1 s −1 13,14. …”

Luminescence and Magnetic Properties of Two Three-Dimensional Terbium and Dysprosium MOFs Based on Azobenzene-4,4′-Dicarboxylic Linker

“…The emission of 2, however, is significantly blue-shifted compared to that of 1, with similar emission bands centered at λ = 475 and 508 nm. The latter shift should be derived from a charge-transfer phenomenon attributed to the breach of a conjugated system of σ and π bonds in the carboxylate groups arisen from the coordination of the ligand and Ln centers, as reported in recent literature in the field [28][29][30].…”

Mononuclear and One‐Dimensional Cobalt(II) Complexes with the 3,6‐Bis(picolylamino)‐1,2,4,5‐tetrazine Ligand

“…[5] Accordingly, symmetric ditopic ligands, prepared either by a modified Pinner synthesis involving the condensation of the corresponding nitriles [1b] or by nucleophilic substitution of the chloro substituents in 3,6dichloro-TTZ, provided a series of dimetallic complexes or coordination polymers. [2] Such ligands include 3,6-dipyridyl-TTZ and its analogues, [6] 3,6-dipyrimidyl-TTZ, [3f,7] 3,6-dibenzocarboxylate-TTZ, [8] 3,6-dicarboxymethyl ester [9] and, more recently, 3,6-groups in equatorial positions and two trans-positioned pyridine nitrogen atoms build the coordination polyhedron around Co1 to form a neutral zigzag chain compound, which cocrystallizes with the mononuclear species trans-[Co 2 (hfac) 2 (CH 3 OH) 2 ]. The magnetic properties of 2 and 3 were investigated in the temperature range 1.9-300 K. The decrease of the M T values of 2 and 3 upon cooling is mainly due to the depopulation of the higher energy Kramers doublets of the magnetically isolated six-coordinate cobalt(II) ions.…”

“…The 1,2,4,5‐tetrazine (TTZ) ring constitutes an interesting platform for mono‐ and ditopic ligands, as the resulting metal complexes can benefit from (i) the strong electron‐withdrawing character of the platform, which allows access to stable radical anion species, (ii) the occurrence of anion–π interactions in the solid state and (iii) emission properties that are highly dependent on the substitution scheme Accordingly, symmetric ditopic ligands, prepared either by a modified Pinner synthesis involving the condensation of the corresponding nitriles[1b] or by nucleophilic substitution of the chloro substituents in 3,6‐dichloro‐TTZ, provided a series of dimetallic complexes or coordination polymers . Such ligands include 3,6‐dipyridyl‐TTZ and its analogues, 3,6‐dipyrimidyl‐TTZ,[3f], 3,6‐dibenzocarboxylate‐TTZ, 3,6‐dicarboxymethyl ester and, more recently, 3,6‐bis(hydrazine)‐TTZ . Moreover, the nucleophilic monosubstitution of 3,6‐dichloro‐TTZ allowed the preparation of monotopic chelating ligands such as dipicolylamine‐TTZ and pyrazolyl‐TTZ derivatives and complexes.…”