Phosphonate Metal–Organic Frameworks: A Novel Family of Semiconductors

Herein, the first semiconducting and magnetic phosphonate metal–organic framework (MOF), TUB75, is reported, which contains a 1D inorganic building unit composed of a zigzag chain of corner‐sharing copper dimers. The solid‐state UV–vis spectrum of TUB75 reveals the existence of a narrow bandgap of 1.4 eV, which agrees well with the density functional theory (DFT)‐calculated bandgap of 1.77 eV. Single‐crystal conductivity measurements for different orientations of the individual crystals yield a range of conductances from 10−3 to 103 S m−1 at room temperature, pointing to the directional nature of the electrical conductivity in TUB75. Magnetization measurements show that TUB75 is composed of antiferromagnetically coupled copper dimer chains. Due to their rich structural chemistry and exceptionally high thermal/chemical stabilities, phosphonate MOFs like TUB75 may open new vistas in engineerable electrodes for supercapacitors.TU Berlin, Open-Access-Mittel - 202

Semiconductive microporous hydrogen-bonded organophosphonic acid frameworks

Herein, we report a semiconductive, proton-conductive, microporous hydrogen-bonded organic framework (HOF) derived from phenylphosphonic acid and 5,10,15,20‐tetrakis[p‐phenylphosphonic acid] porphyrin (GTUB5). The structure of GTUB5 was characterized using single crystal X-ray diffraction. A narrow band gap of 1.56 eV was extracted from a UV-Vis spectrum of pure GTUB5 crystals, in excellent agreement with the 1.65 eV band gap obtained from DFT calculations. The same band gap was also measured for GTUB5 in DMSO. The proton conductivity of GTUB5 was measured to be 3.00 × 10−6 S cm−1 at 75 °C and 75% relative humidity. The surface area was estimated to be 422 m2 g−1 from grand canonical Monte Carlo simulations. XRD showed that GTUB5 is thermally stable under relative humidities of up to 90% at 90 °C. These findings pave the way for a new family of organic, microporous, and semiconducting materials with high surface areas and high thermal stabilities.DFG, 414044773, Open Access Publizieren 2019 - 2020 / Technische Universität Berli

A 3D Cu‐Naphthalene‐Phosphonate Metal–Organic Framework with Ultra‐High Electrical Conductivity

A conductive phosphonate metal–organic framework (MOF), [{Cu(H2O)}(2,6‐NDPA)0.5] (NDPA = naphthalenediphosphonic acid), which contains a 2D inorganic building unit (IBU) comprised of a continuous edge‐sharing sheet of copper phosphonate polyhedra is reported. The 2D IBUs are connected to each other via polyaromatic 2,6‐NDPA's, forming a 3D pillared‐layered MOF structure. This MOF, known as TUB40, has a narrow band gap of 1.42 eV, a record high average electrical conductance of 2 × 102 S m−1 at room temperature based on single‐crystal conductivity measurements, and an electrical conductance of 142 S m−1 based on a pellet measurement. Density functional theory (DFT) calculations reveal that the conductivity is due to an excitation from the highest occupied molecular orbital on the naphthalene‐building unit to the lowest unoccupied molecular orbital on the copper atoms. Temperature‐dependent magnetization measurements show that the copper atoms are antiferromagnetically coupled at very low temperatures, which is also confirmed by the DFT calculations. Due to its high conductance and thermal/chemical stability, TUB40 may prove useful as an electrode material in supercapacitors.TU Berlin, Open-Access-Mittel – 202

Recent chemo-/biosensor and bioimaging studies based on indole-decorated BODIPYs

BODIPY is an important fluorophores due to its enhanced photophysical and chemical properties including outstanding thermal/photochemical stability, intense absorption/emission profiles, high photoluminescence quantum yield, and small Stokes' shifts. In addition to BODIPY, indole and its derivatives have recently gained attention because of their structural properties and particularly biological importance, therefore these molecules have been widely used in sensing and biosensing applications. Here, we focus on recent studies that reported the incorporation of indole-based BODIPY molecules as reporter molecules in sensing systems. We highlight the rationale for developing such systems and evaluate detection limits of the developed sensing platforms. Furthermore, we also review the application of indole-based BODIPY molecules in bioimaging studies. This article includes the evaluation of indole-based BODIPYs from synthesis to characterization and a comparison of the advantages and disadvantages of developed reporter systems, making it instructive for researchers in various disciplines for the design and development of similar systems

Absolute structure determination as a reference for the enantiomeric resolution of racemic mixtures of cyclophosphazenes via chiral high-performance liquid chromatography

Reversed-phase chiral high-performance liquid chromatography (HPLC) is a potentially powerful technique for the enantiomeric resolution of racemic mixtures, although the elution order of enantiomers is only relative and it is necessary to fully characterize reference systems for this method to provide absolute configurational information. The enantiomeric resolution of a series of racemic di-spiro cyclotriphosphazene derivatives, N3P3X2[O(CH2)(3)NH]2 (X = Cl, Ph, SPh, NHPh, OPh) [(1)-(5), respectively] was carried out by reversed-phase chiral HPLC on a commercially available Pirkle-type chiral stationary phase (R,R)-Whelk-01 using 85:15 (v/v) hexane-thf as the mobile phase. The absolute configurations of the resulting enantiomers of compounds (3) (X = SPh) and (5) (X = OPh) were determined unambiguously by X-ray crystallography. For both (3) and (5) it was found that the SS enantiomer eluted before the RR enantiomer, indicating a convenient method to determine the absolute configurations of enantiomers of this series of cyclophosphazene derivatives and providing the first set of enantiomeric reference compounds for cyclophosphazene derivatives. These structures demonstrate an interesting anomaly in that the pair of enantiomers of (3) crystallize in enantiomorphically paired space groups whilst, under the same conditions, the solid-state forms of the enantiomers of (5) form structures in Sohncke space groups that are not enantiomorphous

Phosphonate Metal-Organic Frameworks: A Novel Family of Semiconductors

Herein is reported the first semiconducting and magnetic phosphonate metal-organic framework (MOF), TUB75, which contains a one-dimensional inorganic building unit composed of a zig-zag chain of corner-sharing copper dimers. The solid-state UV-Vis spectrum of TUB75 reveals the existence of a narrow band gap of 1.4 eV, which agrees well with the 1.77 eV one obtained from DFT calculations. Magnetization measurements show that TUB75 is composed of antiferromagnetically coupled copper dimer chains. Due to their rich structural chemistry and exceptionally high thermal/chemical stabilities, phosphonate MOFs like TUB75 may open new vistas in engineerable electrodes for supercapacitors. </p

Carbazole substituted BODIPY dyes: Synthesis, photophysical properties and antitumor activity

In this study, two different BODIPYs containing carbazole groups at the mesa position were designed and synthesized. All compounds were fully characterized by elemental analysis, FT-IR, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, H-1 and C-13 NMR spectroscopy. The photophysical properties of the new compounds were investigated by means of absorption and fluorescence spectroscopies in dilute dichloromethane solutions. We were also interested in the biological activity of these two novel carbazole-linked BODIPYs, particularly concerning their ability to inhibit human colon cancer HT29 cell lines. The photophysical studies revealed strong donor acceptor interaction between carbazole and BODIPY and follow the order compound 5 > compound 4. Also, preliminary assay showed that compound 5 possessed higher cytotoxic activity than compound 4, with IC50 values of 8.3 ng/mL and 21.7 ng/mL respectively. (C) 2015 Elsevier Ltd. All rights reserved.TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [113Z159]We wish to thank TUBITAK (project number -113Z159) for financial support

Structural and computational characterization of 4 ',4 ',6 ',6 '-tetrachloro-3-(2-methoxyethyl)-3H,4H-spiro-1,3,2-benzoxaza phosphinine-2,2 '-[1,3,5,2,4,6]triazatriphosphinine

WOS: 000376050700031In this study a new monospirocyclic phosphazene derivative, 4',4',6',6'-tetrachloro-3-(2-methoxyethyl)3H,4H-spiro [1,3,2-benzoxazaphosphinine-2,2'- [1,3,5,2,4,6] triazatriphosphinine] (SP1) was synthesized from the reaction of hexachlorocyclotriphosphazene (N3P3CI6) with N/0 donor-type, 2-{[(2-Metoxyethyl) amino]methylphenol. The structural investigations of the compound were verified by elemental analyses, MS, FFIR, 1H, 13C, 11 --P NMR spectroscopy and the single crystal X-ray diffraction analysis. The structural and spectroscopic data of the molecule in the ground state were calculated by using density functional method (DFT) using 6-311++G (d, p) basis set. The complete assignments of all vibrational modes were performed on the basis of the total energy distributions (TED). Isotropic chemical shifts (31P, 1H and 13C NMR) were calculated using the gauge-invariant atomic orbital (GIAO) method. Theoretical calculations of bond parameters, harmonic vibration frequencies and nuclear magnetic resonance are in good agreement with experimental results. The electrophilic and nucleophilic attack centers in SP1 were predicted with the local softness values (sit, and si) of individual atoms and it is confirmed that P atoms of the PCl2 groups are nucleophilic attack centers.Kirikkale University, Scientific Research Projects Coordination Unit [2012/14]The authors gratefully acknowledge the financial support from the "Kirikkale University, Scientific Research Projects Coordination Unit" (grant No. 2012/14)

Novel BODIPY-subphthalocyanine dyads with reasonable photodynamic therapy behaviours

In this study, a set of bio-compatible and NIR emissive BODIPY-subphthalocyanine dyads (SP-DBD1-3) that contain amphiphilic triethyleneglycol units supporting partial water solubility and red absorbing BODIPY monomers (DBD1-3) were prepared. The photophysical and photochemical activities of these monomers, including fluorescence behaviors, singlet oxygen production, absorption, and emission profiles were investigated. The effect of the presence of halogen atoms and the BODIPY unit in dyads on the ability of generating singlet oxygen was evaluated. BODIPY-subphthalocyanine dyads showed two absorption bands at about 550 nm and 650 nm and high singlet oxygen quantum yields (up to 91%) at room temperature. The weaker fluorescence emissions, shorter fluorescence lifetimes but better singlet oxygen production capacities of dyads compared to those of BODIPY monomers have been explainedviathe energy transfer process from the donor subphthalocyanine unit to the acceptor BODIPY part, supporting ISC. Also,in vitrostudies underlined that the novel compounds (DBD1,DBD2,SP-DBD-2, andSP-DBD3) were successful in terms of the induction of cell death under red light; however, they did not affect the cells in dark, indicating these compounds as agents that can be used in photodynamic therapyin vivoin further studies

Halogen-Bonded BODIPY Frameworks with Tunable Optical Features

The ability to tune optical features of BODIPY materials is essential for their photo-related application. However, it is challenging to efficiently tune the crystal packing of BODIPY derivatives because of their complex nature. In this study, such control of BODIPY supramolecular assemblies was achieved by designing a BODIPY containing a halogen bond (XB) acceptor (–NO2) and donor (I, Br) to mediate halogen bonding interactions. The mono halogenated 2 and 4 was unable to form XB, whereas 3 and 5 formed isostructural mono-coordinate motif 3, 5-I (1D tubular structure) and symmetric bifurcated motif 5-II (1D zig-zag chains structure) via N-O···I,Br XB interactions. The results show that the dispersion and electrostatic component are the major source of 3, 5-I and 5-II XB formations. The XB interaction between –NO2 and X (I, Br) promote singlet-to-triplet intersystem crossing and triplet-to-singlet reverse intersystem crossing due to delocalization of oxygen electrons partially onto the Br and I. Then this interaction leads to unexpected fluorescence enhancement of 5-II. Finally, the indirect optical band gaps of the 3, 5-I and 5-II were able to be tuned in the range of 1.9–2.50 eV via XB driven crystal packings