Structural changes at the active site of an enzyme induced by binding to a substrate molecule can result in enhanced activity in biological systems. Herein, we report that the new hybrid ultramicroporous material sql‐SIFSIX‐bpe‐Zn exhibits an induced fit binding mechanism when exposed to acetylene, C2H2. The resulting phase change affords exceptionally strong C2H2 binding that in turn enables highly selective C2H2/C2H4 and C2H2/CO2 separation demonstrated by dynamic breakthrough experiments. sql‐SIFSIX‐bpe‐Zn was observed to exhibit at least four phases: as‐synthesised (α); activated (β); and C2H2 induced phases (β′ and γ). sql‐SIFSIX‐bpe‐Zn‐β exhibited strong affinity for C2H2 at ambient conditions as demonstrated by benchmark isosteric heat of adsorption (Qst) of 67.5 kJ mol−1 validated through in situ pressure gradient differential scanning calorimetry (PG‐DSC). Further, in situ characterisation and DFT calculations provide insight into the mechanism of the C2H2 induced fit transformation, binding positions and the nature of host‐guest and guest‐guest interactions.

Thermal management is an important consideration for applications that involve gas sorption by flexible porous materials. A pressure-gradient differential scanning calorimetric method was developed to measure the energetics of adsorption and desorption both directly and continuously. The method was applied to the uptake and release of CO 2 by the well-known flexible metal-organic frameworks MIL-53(Al) and MOF-508b. High-resolution differential enthalpy plots and total integral enthalpy values for sorption allow comprehensive assessment of the thermal behavior of the materials throughout the entire sorption process. During adsorption, the investigated materials display the ability to offset exothermic adsorption enthalpy against endothermic structural transition enthalpy, and vice versa during desorption. The results show that flexible materials offer reduced total integral heat over a working range when compared to rigid materials.

Enthalpyo fs orption (DH)i sa ni mportantp arameter for the design of separation processes using adsorptive materials. A pressure-ramped calorimetric method is described and tested for the direct determination of DH values. Combining ah eatflow thermogram with as ingle sorptioni sotherm enables the determination of DH as af unctiono fl oading. Them ethod is validated by studying CO 2 sorptionb yt he well-studied metalorganic framework Cu-HKUST over at emperature range of 288-318K.T he measured DH values comparew ell with previously reported data determined by using isosterica nd calorimetric methods. The pressure-gradient differential scanning calorimetry (PGDSC) methodp roduces reliable high-resolution results by direct measurement of the enthalpy changes during the sorptionp rocesses. Additionally,P GDSC is less labor-intensive and time-consuming than the isostericm ethod and offers detailedi nsight into how DH changes over ag iven loading range.Porous materials can be utilized for the separation of gaseous mixtures,a sw ell as targeted capturea nd release of specific gases. [1] When evaluating the merits of ag iven porous material for physisorption-based processes (we use "sorption" as ag eneric term for either adsorptiono rd esorption),i ti sn ecessary to consider several important physicochemical factors. These include working capacity,s aturation pressure, hysteresis, kinetics, selectivity,e nthalpies of sorption, and the temperature-dependence of these phenomena. With the exception of enthalpies of sorption, it is possible to measure these parameters directly by using standard sorptioni sotherms, which provide uptake capacity as af unctiono fe quilibrium gas pressure. Bimbo et al. stated that an accurate determination of the enthalpy of adsorption is essential to at horough understanding of any sorption-based system and that its reliable measurement is particularly critical for heat management. [2] Indeed, Chang and Ta lu demonstrated the importanceo fm anaging thermale ffects during sorptions ince temperature changes affect the working capacity of the material( see the Supporting Information, Figure S4). [3] Correct accounting for thermal affects can lead to the developmento farange of sorption-based technologies, which may include heat pumps and cooling systems. [4][5][6] The enthalpy of sorption( DH ads and DH des for adsorption and desorption, respectively)i st he amount of energy generated per mole of guest entering or leaving ah ost. Adsorptioni s an exothermic process with negative enthalpy values, whereas desorption is endothermic with positivee nthalpy values. The enthalpy of sorption encompasses both host-guest and guest-guest interaction energies. [7] However, van der Waalsi nteractions between host and guest are usually the major energetic contributors over the entire loading range. [8] The two most commonm ethods of determining enthalpies of sorption are (i)the indirect isosteric methodb yu sing the Clausius-Clapeyron approximation and (ii)direct measurementb yu sing calorimetry. [9] We note t...

Structural changes at the active site of an enzyme induced by binding to as ubstrate molecule can result in enhanced activity in biological systems.Herein, we report that the new hybrid ultramicroporous material sql-SIFSIX-bpe-Zn exhibits an induced fit binding mechanism when exposed to acetylene,C 2 H 2 .T he resulting phase change affords exceptionally strong C 2 H 2 binding that in turn enables highly selective C 2 H 2 /C 2 H 4 and C 2 H 2 /CO 2 separation demonstrated by dynamic breakthrough experiments.s ql-SIFSIX-bpe-Zn was observed to exhibit at least four phases:as-synthesised (a); activated (b); and C 2 H 2 induced phases (b' and g). sql-SIFSIXbpe-Zn-b exhibited strong affinity for C 2 H 2 at ambient conditions as demonstrated by benchmark isosteric heat of adsorption (Q st )o f6 7.5 kJ mol À1 validated through in situ pressure gradient differential scanning calorimetry (PG-DSC). Further,insitu characterisation and DFT calculations provide insight into the mechanism of the C 2 H 2 induced fit transformation, binding positions and the nature of host-guest and guest-guest interactions.