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Due to their versatility and easy processing, Surface-Anchored Metal–Organic Frameworks (SurMOFs) have gained interest in recent times as promising electrochromic thin films. Herein a step forward in their use and characterization was achieved thanks to the integration of {Zn2(PDICl4)2} SurMOFs in a multi-layer electrochromic device (ECD), based on a membrane-like electrolyte. The optical and electrochemical properties of the ECD were fully characterized, revealing a two-step reduction process localized on the organic ligand and involving subsequent near infra-red (NIR) and cyan absorbing states, leading to optical modulation of the films. The species responsible for this absorption were isolated and identified in the reduced states. In parallel to experimental characterization, quantum chemistry was successfully used to investigate the structure–property relationship of the SurMOF, revealing additional information regarding the structure and the local environment of the electrochromic ligand. [ABSTRACT FROM AUTHOR]

Novel electrochromic hybrid thin films are synthesized following a liquid‐phase epitaxy in a layer‐by‐layer fashion, yielding highly oriented surface‐anchored metal–organic frameworks (SurMOFs). The initial orange color of this {Zn2(PDICl4)2} crystalline thin films is reversibly switched by electrochemical reduction. In a lithium‐based electrolyte, a dark blue color is obtained in few seconds with a color efficiency of 104.8 cm2 C−1 (λ = 645 nm). Interestingly, the color of the reduced state is easily modulated by changing the electrolyte composition. Clearly, two different mechanisms are implicated and the reduced species responsible of the color are identified. Taking advantage of this unusual property, electrochromic devices with a novel configuration are designed leading to an original prototype capable of reversibly switching from a single initial orange color to two different colors simultaneously, namely dark blue and cyan. [ABSTRACT FROM AUTHOR]

When chromophores are brought into close proximity, noncovalent interactions (π-π/CH-π) can lead to the formation of excitonically coupled states, which bestow new photophysical properties upon the aggregates. Because the properties of the new states not only depend on the strength of intermolecular interactions, but also on the relative orientation, supramolecular assemblies, where these parameters can be varied in a deliberate fashion, provide novel possibilities for the control of photophysical properties. This work reports that core-substituted naphthalene diimides (cNDIs) can be incorporated into surface-mounted metal- organic structures/frameworks (SURMOFs) to yield optical properties strikingly different from conventional aggregates of such molecules, for example, formed in solution or by crystallization. Organic linkers are used, based on cNDIs, well-known organic chromophores with numerous applications in different optoelectronic devices, to fabricate MOF thin films on transparent substrates. A thorough characterization of the properties of these highly ordered chromophoric assemblies reveals the presence of non-emissive excited states in the crystalline material. Structural modulations provide further insights into the nature of the coupling that gives rise to an excited-state energy level in the periodic structure. [ABSTRACT FROM AUTHOR]

Two azaBODIPY derivatives bearing two divergently oriented benzonitrile groups at the distal positions have been used as tectons for the construction of coordination polymers, upon assembly with Ag(i) salts. [ABSTRACT FROM AUTHOR]

Abstract: Photochemical reactions typically proceed via multiple reaction pathways, yielding a variety of isomers and products. Enhancing the selectivity is challenging. Now, the potential of supramolecular control for oxidative photocyclization of a tetraarylethylene, containing a stereogenic −C=C− bond, is demonstrated. In solution, this photochemical reaction produces three constitutional isomers (substituted phenanthrenes), with slow kinetics. When the reactant is assembled into a crystalline framework, only one product forms with accelerated kinetics. Key to this selectivity enhancement is the integration into a surface grown metal–organic framework (SURMOF); the dramatic gain in selectivity is ascribed to the hindrance of the rotational freedom of the −C=C− double bond. The structure of the MOF is key; the corresponding reaction in the solid does not result in such a high increase in selectivity. A striking change of luminescence properties after photocyclization is observed. [ABSTRACT FROM AUTHOR]

Abstract: Photochemische Reaktionen verlaufen typischerweise über mehrere Reaktionswege und führen zu einer Vielfalt von Produkten. Die Verbesserung ihrer Selektivität ist anspruchsvoll. Hier wird das Potential einer supramolekularen Steuerung für die photooxidative Zyklisierung eines Tetraaryleethylens (oder substituierten Stilbens) mit stereogener C=C‐Bindung demonstriert. In Lösung führt diese langsame photochemische Reaktion zu drei Phenantren‐Konstitutionsisomeren. Wird die Startverbindung in einen kristallinen Rahmen gesetzt, bildet sich nur ein Reaktionsprodukt, und die Reaktion wird erheblich beschleunigt. Entscheidend ist hier die Integration in ein SURMOF; die drastische Selektivitätszunahme wird auf die Einschränkung der Rotationsfreiheit der C=C‐Bindung zurückgeführt. Die Struktur des MOF ist verantwortlich für diesen Erfolg; die entsprechende Reaktion im Festkörper führt nicht zu einem solch starken Selektivitätsanstieg. Außerdem ist nach der photooxidativen Zyklisierung eine erhebliche Veränderung der Lumineszenzeigenschaften zu beobachten. [ABSTRACT FROM AUTHOR]