AbstractDie Entwicklung von multifunktionalen Materialien, die die Hell‐Dunkel‐Entkopplung der natürlichen Photosynthese nachahmen, ist eine zentrale Herausforderung im Bereich der Energieumwandlung. In diesem Artikel stellen wir MnBr‐253 vor, eine edelmetallfreie metall‐organische Gerüstverbindung (MOF), die aus Al‐Metallknotenpunkten, Bipyridin Linkern und MnBr(CO)3(Bipyridin)‐Komplexen aufgebaut ist. Bei Bestrahlung zeigen die MnBr‐253 Kolloide eine Elektronen‐Photoladekapazität von ~42 C ⋅ g−1MOF, mit kompetetiver Photoladerate (1.28 C ⋅ s−1 ⋅ g−1MOF) und einer Umwandlungseffizienz von einfallenden Photonen in Elektronen von ~9,4 % bei 450 nm. Spektroskopische und rechnerische Studien belegen eine effektive Elektronenakkumulation an dem Mn‐Komplex, während die hohe Porosität und Mn‐Beladung die bemerkenswerte Elektronenspeicherleistung erklären. Die geladenen MnBr‐253‐Pulver wurden erfolgreich für die Wasserstoffproduktion unter dunklen Bedingungen eingesetzt und damit die vom Licht entkoppelte Reaktivität der Photosynthese nachgeahmt.

Designing multifunctional materials that mimic the light-dark decoupling of natural photosynthesis is a key challenge in the field of energy conversion. Herein, we introduce MnBr-253, a precious metal-free metal-organic framework (MOF) built on Al nodes, bipyridine linkers and MnBr(CO)3(bipyridine) complexes. Upon irradiation, MnBr-253 colloids demonstrate an electron photocharging capacity of ~42 C ⋅ g-1 MOF, with state-of-the-art photocharging rate (1.28 C ⋅ s-1 ⋅ g-1 MOF) and incident photon-to-electron conversion efficiency of ~9.4 % at 450 nm. Spectroscopic and computational studies support effective electron accumulation at the Mn complex while high porosity and Mn loading account for the notable electron storage performance. The charged MnBr-253 powders were successfully applied for hydrogen evolution under dark conditions thus emulating the light-decoupled reactivity of photosynthesis.

The properties of cuprophilic compounds and the underlying fundamental principles responsible for the Cu(I)Cu(I) interactions have been the subject of intense research as their diverse structural and physical attributes are being explored. In this light, we performed a new study of the compound [Cu10O2(Mes)(6)] reported by Haakansson et al. using state of the art experimental and theoretical analysis techniques. Doing this, we found the compound to be a polymer in the solid state, best written as [Cu10O2(Mes)(6)](n), with unsupported Cu(I)Cu(I) contacts linking the monomers (2.776 & Aring;). The monomeric unit also exhibits various cuprophilic contacts bridged by mesityl and/or oxo ligands. The compound was analyzed in its solid state, revealing luminescent properties resulting from two distinct fluorescent emissions, as well as in solution, in which its polymeric structure reversibly decomposes. A quantum theory of atoms in molecules (QTAIM) analysis based on density functional theory (DFT) calculations allows to characterize the various Cu(I)Cu(I) contacts, in which only a few, and not necessarily the shortest, are associated with a bond critical point. Additionally, an energy decomposition analysis of the bonding between monomers indicates that it is dominated by dispersion forces in which the ligands play a dominant role, resulting in bonding energies significantly larger than found in previous DFT investigations based on less bulky models.

Coordination polymers (CP) and their subgroup metal–organic frameworks (MOF) are promising classes of modular multiphoton-absorption active materials. However, a detailed knowledge of the structure–property relationship or generalized design principles remains elusive. This study examines how various packings of the chromophore linker 9,9′-stilbene-bis-carbazole-3,6-dicarboxylic acid in three synthesized zinc-based CPs affect their MPA activity. Different spatial chromophore arrangements are achieved by the so-called "pillar-layer" synthesis approach, using the chromophore and two different additional pillar linkers (4,4′-bipyridine and 1,2-bis(4-pyridyl)ethane) for CP formation. Two novel pillar-layered CPs, Zn2n(sbcd)(bpy)(DMAc)2n(H2O)3n and Zn2n(sbcd)(bpe)(DMAc)3n(H2O), are reported and examined in their two-photon-absorption-induced photoluminescence and compared to a previously synthesized CP Zn2n(sbcd)(DMAc)2n(H2O)1.5n, containing the same chromophore but no pillars. The comparison shows significant differences for the two-photon absorption cross-sections of the materials, improving it by incorporating the pillar. Our findings point toward the significance of controlling the chromophore orientation to tailor the nonlinear optical properties of the materials. These insights pave the way toward an aim-directed development of MOFs for advanced photonic applications.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Three new coordination polymers (CPs) constructed from the linker 1,4-di(dithiocarboxylate) (BDDTC2-)-the sulfur-analog of 1,4-benzenedicarboxylate (BDC2-)-together with Mn-, Zn-, and Fe-based inorganic SBUs are reported with description of their structural and electronic properties. Single-crystal X-ray diffraction revealed structural diversity ranging from one-dimensional chains in [Mn(BDDTC)(DMF)(2)] (1) to two-dimensional (2D) honeycomb sheets observed for [Zn-2(BDDTC)(3)][Zn(DMF)(5)(H2O)] (2). Gas adsorption experiments confirmed a 3D porous structure for the mixed-valent material [Fe-2(BDDTC)(2)(OH)] (3). 3 contains a 1:1 ratio of Fe2+/3+ ions, as evidenced by Fe-57 Mossbauer, X-band EPR, and X-ray absorption spectroscopy. Its empirical formula was established by elemental analysis, thermal gravimetric analysis, infrared vibrational spectroscopy, and X-ray absorption spectroscopy in lieu of elusive single-crystal X-ray diffraction data. In contrast to the Mn- and Zn-based compounds 1 and 2, the Fe2+/3+ CP 3 showed remarkably high electrical conductivity of 5 x 10(-3) S cm(-1) (according to van der Pauw measurements), which is within the range of semiconducting materials. Overall, our study confirms that sulfur derivatives of typical carboxylate linkers (e.g., BDC) are suitable for the construction of electrically conducting CPs, due to acceptedly higher covalency in metal-ligand bonding compared to the electrically insulating carboxylate CPs or metal-organic frameworks. At the same time, the direct comparison between insulating CPs 1 and 2 with CP 3 emphasizes that the electronic structure of the metal is likewise a crucial aspect to construct electrically conductive materials.

Multiphoton absorption (MPA), as a subgroup of non-linear optical effects, is of high interest in modern materials research since it has a great applicability in optoelectronics. However, most of the commonly used materials featuring MPA properties are chromophore molecules, which are limited by their thermal stability and uncontrolled aggregation in high-concentration solutions. A prominent material class which could in principle overcome these problems are metal-organic frameworks and coordination polymers (CPs) as they can be modularly tuned to possess chemical and thermal stability. In addition, by incorporating chromophores as linkers in the framework, their molecular properties can be retained or even enhanced. In this article, we report the synthesis and characterization of three new and highly MPA-active CPs, Zn-2(sbcd)(DMAc)(2)(H2O)(1.5), Sr(fbcd)(DMAc)(0.25)(H2O)(3.5), and Ba(fbcd)(DMAc)(2.5)(H2O)(1.5), based on two carbazole-containing chromophore linkers: a previously reported 9,9'-stilbene-bis-carbazole-3,6-dicarboxylic acid (H(4)sbcd) and the new 2,7-fluorene-9,9'-dimethyl-bis-carbazole-3,6-dicarboxylic acid (H(4)fbcd). Single-crystal structure analysis of the zinc-based CP reveals a sql network, whereas the barium- and strontium-based CPs are isostructural, showing a 4,8-c network topology. Z-scan analysis of the networks shows large two-photon absorption cross-sections sigma((2)) of 2100 to 33,300 GM, which is an enhancement of up to 3 orders of magnitude in comparison to the solvated linker and is also one of the highest MPA-cross-sections reported for CPs up to date.

In the face of anthropogenic global warming the design and synthesis of materials, which enable energy transfer processes using sunlight as an energy source, are of high interest. Perylenediimides are a highly absorbing class of chromophores suitable for sunlight absorption and conversion. Therefore, metal–organic frameworks (MOFs) and coordination polymers (CPs) with incorporated organic perylene chromophores are highly interesting materials both for applied, but also fundamental, photophysical research. MOFs/CPs have the advantage of a modular adjustability of interchromophoric distances and angles, and the choice of metal nodes can be used to further tune the material towards the desired photophysical properties. In the present paper, we present a study using a reported organic perylenediimide (PDI) chromophore (H2tpdb) as a linker to be incorporated into coordination polymer and test towards applicability within the photochemical 1O2 generation. In detail, a novel zinc 2D -coordination polymer Zn(tpdb)(DMF)3 is reported, which is synthesized using a solvothermal synthesis with Zn(NO3)2 and a ditopic organic perylene linker. Both the linker and Zn-CP are fully characterized, including SC-XRD, showing a strong aggregation of tightly packed chromophores in the solid state. The photophysical properties are examined and discussed, including the observed shifts within the absorption spectra of the CP are compared to the linker in solution. These shifts are mainly attributed to the for PDIs known H-type aggregation and an additional charge transfer in the framework structure, causing a limited quantum yield of the emission. Finally, the photosensitization of triplet oxygen to singlet oxygen using 1,3-diphenylisobenzofurane (DBPF) as a trapping agent is investigated both for the free linker and the Zn-CP, showing that the perylene chromophore is an efficient photosensitizer and its activity can, in principle, be retained after its incorporation in the coordination polymer.