Dawei Zhang

Les hémicryptophanes : Synthèse, Reconnaissance, Machines Moléculaires et Catalyse Supramoléculaire: Les hémicryptophanes, molécules constituées d’une unité cyclotriveratrylène (CTV) reliée à un autre groupement de symétrie C3, sont des molécules cages qui trouvent de nombreuses applications dans le domaine de la chimie hôte-invité. Dans une première partie, ce manuscrit présente une revue des développements récents de la chimie des hémicryptophanes et définit les objectifs de ce travail de thèse.Nos travaux concernent principalement le design d'hémicryptophanes spécifiquement conçus pour la reconnaissance moléculaire de substrats d'intérêt. Ainsi, des structures variées d'hémicryptophanes ont été conçues comme capteur fluorescent du phosphate de choline, ou pour la reconnaissance de paire d'ions. Des hémicryptophanes hétéroditopiques originaux portant des unités tris(2-pyridylmethyl)amine (TPA) ont été synthétisés et présentent un grand intérêt pour des applications ultérieures en reconnaissance. Nous avons étudié la reconnaissance stéréosélective de saccharides avec des hémicryptophanes énantiopurs qui associent trois types de chiralité sur sept centres stéréogènes. Enfin, nous décrivons le mouvement de "respiration" moléculaire de cages énantiopures, enrichissant ainsi les rares applications des hémicryptophanes comme machines moléculaires.Des complexes du vanadium(V) des hémicryptophanes ont été développés comme catalyseurs efficaces dans des réactions de sulfoxydation et pour l'oxydation catalytique de lignines. Des dérivés azaphosphatrane d’hémicryptohanes ont été développés comme organocatalyseurs de la réaction de polymérisation par ouverture du lactide. La dernière partie de ce manuscript est consacrée à des développements nouveaux dans le domaine de la formation de cages par auto-assemblage. Nous avons réussi à former par coordination des tétraèdres dont les quatre faces comportent une sous-unité azaphosphatrane. Nous montrons pour la première fois que dans ce type de cage l’unité azaphosphatrane joue un rôle prépondérant dans la complexation d’anions.

The development of nanoscale chiral materials with enhanced optical properties holds significant promise for advancing technologies in light-emitting devices and enantioselective sensing. Here, we report the self-assembly of chiral metal–organic cages from an axially chiral, AIE-active binaphthyl dicarboxylate ligand. This supramolecular architecture functions as a multifunctional platform, demonstrating a high affinity for anionic guests through synergistic electrostatic and hydrogen-bonding interactions. The rigid cage framework not only enhances the ligand’s intrinsic aggregation-induced emission (AIE) but also serves as a highly effective chiral amplifier. Notably, MOCs significantly boost the circularly polarized luminescence (CPL), achieving a luminescence dissymmetry factor (|g_lum|) of 1.2 × 10⁻³. This value represents an approximately five-fold enhancement over that of the unassembled ligand. The photophysical properties of this chiral supramolecular system provide a strategic blueprint for designing next-generation optical nanomaterials.

The management of iodine species, notorious for their environmental persistence and health risks, requires innovative materials capable of efficient capture and conversion. Herein, we report the self‐assembly and characterization of a Zr‐based metal–organic tetrahedron ( 1 ) functionalized with redox‐active triazatriangulenium (TATA ⁺ ) panels. The cage exhibits a high binding affinity for triiodide (I ₃ ⁻ ) (ca. 10 ⁶ M ⁻¹ ) in methanol. The strong host–guest complexation significantly facilitates the disproportionation hydrolysis of I ₂ to generate I ₃ ⁻ and HOI. It also enables photocatalytic aerobic oxidation of I ⁻ into I ₃ ⁻ within its cavity. Mechanistic investigations revealed the key steps involving guest‐to‐host photoinduced electron transfer (ET) to generate radicals I ^• and 1 ^• and ET from 1 ^• to dioxygen to generate superoxide. Solid‐state adsorption experiments showed the rapid removal of I ₂ and I ₃ ⁻ from water by 1 ‐NTf ₂ because of the high affinity for polyiodides. Importantly, although solid‐state 1 ‐NTf ₂ has no ability to directly adsorb I ⁻ from water, we have for the first time developed a light‐driven strategy that enables removal of I ⁻ through coupled photooxidation and sequestration. This work highlights the significant potential of integrating photoredox‐active moieties within stable metal–organic cages for controlling iodine binding and speciation and opens new avenues to address environmental and energy‐related sequestration challenges.

Developing synthetic hosts capable of binding sulfonate anions or sequestering perfluorosulfonates is highly important. In this work, the self‐assembly of a tripyridinium‐tricarboxylate ligand with Cp ₂ ZrCl ₂ (Cp = η ⁵ ‐C ₅ H ₅ ) is reported, yielding a highly cationic tetrahedral cage ( 1 ) engineered with acidic C−H protons. The hexadecacationic cage binds a variety of sulfonate anions with unprecedented charge‐discriminative phenomena: the cage binds monosulfonates in fast exchange on the NMR timescale, while di‐ and multisulfonates exhibit slow‐exchange binding. In particular, high‐capacity complexation of di‐ and trisulfonates by 1 is achieved, with the pronounced case of 1 accommodating three dianions. Molecular modeling suggests the existence of a “Y”‐shaped binding pocket on each edge of tetrahedron 1 (six in total), with each pocket capable of anchoring a guest bearing at least two sulfonate headgroups through electrostatic and hydrogen bonding interactions. Further investigations demonstrate that 1 in solid state is an exceptional adsorbent for perfluorooctane sulfonate (PFOS), with a maximum adsorption capacity of up to 1603 mg g ⁻¹ positioning it among the top PFOS adsorbents. Moreover, cage 1 exhibits rapid kinetics, high selectivity, and long‐life cycles in PFOS removal, and also effectively adsorbs shorter perfluorosulfonates.

Macrocyclic hosts are pivotal in supramolecular chemistry, yet the discovery of synthetically scalable platforms that combine rich host-guest behavior, facile crystallizability, and solid-state functionality remains a challenge. Here, we present the synthesis of a new cyclic BODIPY array, trimer 1, composed of three BODIPY units linked by m-phenylene spacers. Two dynamic conformers of 1, namely, cone-shaped c-1 and partial-cone-shaped pc-1, exist in solution and have been characterized by their X-ray crystal structures. These two conformers undergo interconversion in response to changes in external environments, including solvents and guests. Conformer c-1 is capable of hosting neutral guests bearing electron-deficient methyl groups in solution, driven by collective C-H···F interactions, while cationic guests with ammonium groups are preferentially hosted by conformer pc-1. Crystallization conditions were optimized, enabling the preparation of gram-scale crystals of c-1 with different packing arrangements, designated as c-1a and c-1b. Activation of these two samples led to transformations from single-crystal to single-crystal or to amorphous, yielding crystalline c-1a' and amorphous c-1b', respectively. Importantly, crystalline c-1a' exhibits excellent adsorption capacity and separation selectivity for hydrogen isotopes, benefiting from its permanent ultramicroporosity. In contrast, amorphous c-1b' is an effective adsorbent for molecular iodine, with binding interactions fully elucidated through X-ray crystallographic analysis. This work establishes cyclic BODIPY arrays as a highly tunable platform for creating adaptive molecular solids with applications in separation science, moving beyond their inherent optical properties.

Engineering molecular recognition events into catalytic systems to precisely control the up‐ or down‐regulation of catalysis in a biomimetic fashion is a challenging goal in supramolecular chemistry. In this work, we report on the construction of a new metal–organic cage, Zn ^II ₄ L ₄ tetrahedron 1 , using a protonated azacalix[3](2,6)pyridine‐based ligand as the capping faces. The cage features a large cavity and wide gaps between its faces, enabling the simultaneous binding of anionic guests centrally and peripherally. Encapsulation of α‐Mo ₈ O ₂₆ ⁴⁻ within the T ‐symmetric tetrahedron 1 leads to a C ₃ ‐symmetric inclusion complex Mo ₈ O ₂₆ ⁴⁻ ⊂ 1 . The apertures of Mo ₈ O ₂₆ ⁴⁻ ⊂ 1 act as secondary binding sites for accommodating tetraarylborate guests or for providing access to the included Mo ₈ O ₂₆ ⁴⁻ for catalyzing reactions. Catalytic experiments demonstrated that inclusion within 1 significantly enhances the catalytic activity of Mo ₈ O ₂₆ ⁴⁻ for the oxidation of sulfides into sulfoxides. In contrast, peripheral binding of the bulky tetraarylborate anion to the inclusion complex Mo ₈ O ₂₆ ⁴⁻ ⊂ 1 effectively inhibits its catalytic activity by obstructing access to the catalytic active sites of Mo ₈ O ₂₆ ⁴⁻ .

Engineering molecular recognition events into catalytic systems to precisely control the up‐ or down‐regulation of catalysis in a biomimetic fashion is a challenging goal in supramolecular chemistry. In this work, we report on the construction of a new metal–organic cage, Zn ^II ₄ L ₄ tetrahedron 1 , using a protonated azacalix[3](2,6)pyridine‐based ligand as the capping faces. The cage features a large cavity and wide gaps between its faces, enabling the simultaneous binding of anionic guests centrally and peripherally. Encapsulation of α‐Mo ₈ O ₂₆ ⁴⁻ within the T ‐symmetric tetrahedron 1 leads to a C ₃ ‐symmetric inclusion complex Mo ₈ O ₂₆ ⁴⁻ ⊂ 1 . The apertures of Mo ₈ O ₂₆ ⁴⁻ ⊂ 1 act as secondary binding sites for accommodating tetraarylborate guests or for providing access to the included Mo ₈ O ₂₆ ⁴⁻ for catalyzing reactions. Catalytic experiments demonstrated that inclusion within 1 significantly enhances the catalytic activity of Mo ₈ O ₂₆ ⁴⁻ for the oxidation of sulfides into sulfoxides. In contrast, peripheral binding of the bulky tetraarylborate anion to the inclusion complex Mo ₈ O ₂₆ ⁴⁻ ⊂ 1 effectively inhibits its catalytic activity by obstructing access to the catalytic active sites of Mo ₈ O ₂₆ ⁴⁻ .

Three new coordination polymers, {[M(nbpdc)(DMF)(H₂O)₂]·H₂O}_∞ (M = Co and Ni) and [Zn(nbpdc)(DMF)(H₂O)]_∞, were synthesized from 2-nitrobiphenyl-4,4′-dicarboxylate (nbpdc²⁻). The isomorphous Co(II) and Ni(II) compounds exhibited a two-dimensional coordination network in which the chains with single-water bridges and the chains with single-nbpdc²⁻ bridges intersected each other by sharing the metal ions. The coordination networks were connected with uncoordinated water molecules through hydrogen bonds. The rarely identified single-water-bridged coordination chain was reinforced by water-based intrachain hydrogen bonds. The single-water bridges mediated modest antiferromagnetic superexchange in both Co(II) and Ni(II) compounds and afforded a spin-canting structure for the Co(II) compound at low temperatures. Water molecules played a distinct structural role in the Zn(II) compound, which was a one-dimensional coordination polymer with single-nbpdc²⁻ bridges. Instead of bridging metal ions, each water molecule was coordinated to one metal ion and hydrogen-bonded to the coordination spheres of other two metal ions, resulting to an infinite ladderlike hydrogen-bonding motif. The ladders interlinked the nbpdc-bridged chains into a three-dimensional supramolecular architecture featuring the 5-conneted {4⁴.6⁴} net.

Flexible metal–organic cages can provide confined active metal sites and show promise in mimicking metalloenzymes. In this study, we synthesized two flexible chiral bimetallic coordination cages, [(PEt3)6Pt3(R,R,R-VL)2]6+ and its enantiomer, through the self-assembly of platinum(II) precursors with enantiopure tripodal vanadium(V) complexes bearing pendant pyridyl groups (VL). The cages show guest binding with chiral camphorsulfonate anions, concomitant with changes in the cage conformation. The catalytic properties of the cage for oxidizing thioethers into chiral sulfoxides were investigated in comparison with a simple chiral vanadium(V) complex. While the simple complex, either alone or along with camphorsulfonate, does not show any enantioselectivity, the cage alone enables enantioselective oxidation even though the enantiomeric excess is low. The stereoselectivity is significantly improved after the camphorsulfonate guest is introduced to the cage. The chiral guest acts like an allosteric effector for enzymes to modulate the cage conformation and the local microenvironment around the catalytic site in favor of chiral induction. This work highlights the potentials of leveraging cage-confined catalytic sites and host–guest interactions for advancing supramolecular asymmetric catalysis.

Intensified host-guest electronic interplay within stable metal-organic cages (MOCs) presents great opportunities for applications in stimuli response and photocatalysis. Zr-MOCs represent a type of robust discrete hosts for such a design, but their host-guest chemistry in solution is hampered by the limited solubility. Here, by using pyridinium-derived cationic ligands with tetrakis(3,5-bis(trifluoromethyl)phenyl)borate (BAr_F⁻) as solubilizing counteranions, we report the preparation of soluble Zr-MOCs of different shapes (1-4) that are otherwise inaccessible through a conventional method. Enforced arrangement of the multiple electron-deficient pyridinium groups into one cage (1) leads to magnified positive electrostatic field and electron-accepting strength in favor of hosting electron-donating anions, including halides and tetraarylborates. The strong charge-transfer (CT) interactions activate guest-to-host photoinduced electron transfer (PET), leading to pronounced and regulable photochromisms. Both ground-state and radical structures of host and host-guest complexes have been unambiguously characterized by X-ray crystallography. The CT-enhanced PET also enables the use of 1 as an efficient photocatalyst for aerobic oxidation of tetraarylborates into biaryls and phenols. This work presents the solution assembly of soluble Zr-MOCs from cationic ligands with the assistance of solubilizing anions and highlights the great potential of harnessing host-guest CT for boosting PET-based functions and applications.