Three chiral carbonyl hypoiodites, R-C(O)OI, have been prepared from N-protected (S)-valine to give the ligand-stabilised (S)-valinoyl hypoiodite complexes with 4-dimethylaminopyridine, 4-pyrrolidinopyridine, and 4-morpholinopyridine as the stabilising ligands. The identity of...
Moisture excess in buildings constitutes a complex problem affecting indoor air quality, energy consumption and the lifetime of the building envelope. We investigate the effect on moisture transfer in structures as a positive pressure is applied inside the enclosure. It is found that, contrary to established belief, the positive pressure does not induce any negative effects on the structures’ moisture content in normally ventilated classrooms, even with high occupancy. Our case study consists of a school building in Finland, subject to temperature and relative humidity measurements after a small (5–7 Pa) positive pressure was realized through ventilation control. We first address analytically the moisture excess generated inside the classrooms for 14 days, using dynamical balance equations that account for both ventilation effects and occupants’ moisture release in the environment. It is found that the average moisture excess is very small, largely below 1 g/m3, even for ventilation rates that are half the design value. We also examine the moisture performance of the envelope, by addressing the moisture migration at upper and lower joints of the external walls for both measured and design values of the indoor absolute humidity (AH). A coupled numerical model of diffusion and convection shows that moisture accumulation in the envelope and the according stresses are negligible for any realistic AH values. This result is in agreement with field measurements at the school. In conclusion, it seems that applying a small overpressure in a well-ventilated school building during a standard service period resulted in no accumulation inside the external walls, even at high occupancy and with low ventilation. Remarkably, it slightly dried out the moisture content in structures under actual occupancy conditions. The positive pressure has accordingly no negative effects on moisture performance, and is capable to guarantee a good indoor air quality as well.
A series of thiourea‐based tritopic receptor molecules were synthesized to be used as building blocks for halogen‐bonded assemblies. Here, 16 new receptor molecules were synthesized from two different 2,4,6‐trialkyl‐1,3,5‐tris(bromomethyl)benzene starting materials via tris(isothiocyanatomethyl)benzene intermediates. The alkyl substituents in the benzene ring proved to be important for isothiocyanate group formation instead of competing thiocyanate group. The synthesis route allowed us to synthesize the isothiocyanate intermediates and further the receptor molecules without the typically used and highly toxic thiophosgene. The synthesized receptor molecules were used to study their halogen‐bond acceptor properties with diiodotetrafluorobenzene donors by single‐crystal X‐ray diffraction method. We were able to obtain five new crystal structures of halogen‐bonded complexes, in which all receptors showed two to four accepted C−I⋅⋅⋅S halogen bonds. The observed halogen bonds were highly directional and showed large variation in C=S⋅⋅⋅I acceptor angles, indicating flexible acceptor properties of sulfur.
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