23 research outputs found

    Synthese von Buckybowls mittels eines Algorithmus zur Aktivierung von C-FBindungen an Aluminiumoxid

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    The unique nature of the alumina‐mediated cyclodehydrofluorination gives the opportunity to execute the preprogrammed algorithm of the C−C couplings rationally built into a precursor. Such multi‐assemblies facilitate the construction of the carbon‐skeleton, superseding the conventional step‐by‐step by the one‐pot intramolecular assembly. In this work, the feasibility of the aluminamediated C−F bond activation approach for multi‐assembly is demonstrated on the example of a fundamental bowl‐shaped polycyclic aromatic hydrocarbon (diindenochrysene) through the formation of all “missing” C−C bonds at the last step. Among valuable insights into the reaction mechanism and the design of the precursors, a facile pathway enabling the two‐step synthesis of diindenochrysene was elaborated, in which five C−C bonds form in a single synthetic step. It is shown that the relative positions of fluorine atoms play a crucial role in the outcome of the assembly and that governing the substituent positions enables the design of effective precursor molecules “programmed” for the consecutive C−C bond formations. In general, these findings push the state of the field towards the facile synthesis of sophisticated bowl‐shaped carbon‐based nanostructures through multi‐assembly of fluoroarenes

    Alumina-Mediated π-Activation of Alkynes

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    An Indacenopicene‐based Buckybowl Catcher for Recognition of Fullerenes

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    A novel buckybowl catcher with an extended π-surface has been synthesized via cross-coupling of two bowl shaped bromoindacenopicene moieties with a tolyl linker. The obtained catcher has been unambiguously characterized by 2D-NMR and mass spectrometry. DFT calculations indicate that the curved shape of the receptor moieties is favourable for binding fullerenes. Effective binding was confirmed for interactions with C60_{60} and C70_{70} utilizing NMR spectroscopy and isothermal titration calorimetry (ITC). The resulting binding values show a higher affinity of the catcher towards C70_{70} over C60_{60}. The designed catcher demonstrated the fundamental possibility of creating sensors for spherical aromaticity

    Moisture behavior calculation of single-layer enclosing structure by means of discrete-continuous method

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    The paper proposes mathematical model for unsteady-state moisture behaviour calculation of single-layer enclosing structures by means of moisture potential and discrete-continuous method. A formula for moisture potential value calculation for single-layer enclosing structure in any enclosing structure section, at any moment of time, under continuous control for temperature distribution, has been derived. Moisture transfer between the enclosing structure and ambient air is taken into account by means of third-kind boundary conditions. Temperature distribution is taken as constant during a month. The proposed method allows for moisture potential determination according to the proposed formula for every month. Calculation results obtained by the proposed method, well-known unsteady-state method and engineering method developed by V.G. Gagarin and V.V.Kozlov have been compared for single-layer enclosing structure made of aerated concrete. It was shown that average value calculation results disagreement does not exceed 7% for the proposed method and unsteady-state method. However, the proposed approach allows for moisture distribution determination using analytical expression, which is convenient for use in engineering practice

    Assessment of enclosing structure moisture regime using moisture potential theory

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    The paper describes principal development directions of mathematical models of enclosing structure moisture regime. Benefits of mathematical models based on moisture potential theory are demonstrated. Moisture regime calculation by means of moisture potential, taking liquid and vapor moisture transfer into consideration, and using discrete-continual approach is proposed. New formulas for single-layer and multi-layer enclosing structures allowing for numerical analytic determination of moisture potential value in any enclosing structure section, at any moment of time, under continuous control of temperature distribution, have been derived. Moisture distribution has been studied for a number of enclosing structures using different methods of moisture potential theory: unsteady-state method, quasi-stationary method, the proposed discrete-continual method. Moisture regime has been determined for single-layer enclosing structure with ceramic brick basement and lime brick cladding in Moscow. It is shown that the greatest moisture value is achieved in enclosing structure calculation by means of steady-state method. Unsteady-state method gives more accurate moisture distribution. The proposed discrete-continual method gives quantitative and qualitative result of moisture distribution similar to results obtained by unsteady-state method. The benefit of discrete-continual method is a distribution obtained analytically, which allows to use solution results without numerical method application

    Moisture behavior calculation of single-layer enclosing structure by means of discrete-continuous method

    No full text
    The paper proposes mathematical model for unsteady-state moisture behaviour calculation of single-layer enclosing structures by means of moisture potential and discrete-continuous method. A formula for moisture potential value calculation for single-layer enclosing structure in any enclosing structure section, at any moment of time, under continuous control for temperature distribution, has been derived. Moisture transfer between the enclosing structure and ambient air is taken into account by means of third-kind boundary conditions. Temperature distribution is taken as constant during a month. The proposed method allows for moisture potential determination according to the proposed formula for every month. Calculation results obtained by the proposed method, well-known unsteady-state method and engineering method developed by V.G. Gagarin and V.V.Kozlov have been compared for single-layer enclosing structure made of aerated concrete. It was shown that average value calculation results disagreement does not exceed 7% for the proposed method and unsteady-state method. However, the proposed approach allows for moisture distribution determination using analytical expression, which is convenient for use in engineering practice

    Assessment of enclosing structure moisture regime using moisture potential theory

    No full text
    The paper describes principal development directions of mathematical models of enclosing structure moisture regime. Benefits of mathematical models based on moisture potential theory are demonstrated. Moisture regime calculation by means of moisture potential, taking liquid and vapor moisture transfer into consideration, and using discrete-continual approach is proposed. New formulas for single-layer and multi-layer enclosing structures allowing for numerical analytic determination of moisture potential value in any enclosing structure section, at any moment of time, under continuous control of temperature distribution, have been derived. Moisture distribution has been studied for a number of enclosing structures using different methods of moisture potential theory: unsteady-state method, quasi-stationary method, the proposed discrete-continual method. Moisture regime has been determined for single-layer enclosing structure with ceramic brick basement and lime brick cladding in Moscow. It is shown that the greatest moisture value is achieved in enclosing structure calculation by means of steady-state method. Unsteady-state method gives more accurate moisture distribution. The proposed discrete-continual method gives quantitative and qualitative result of moisture distribution similar to results obtained by unsteady-state method. The benefit of discrete-continual method is a distribution obtained analytically, which allows to use solution results without numerical method application
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