On thio-substituted N-heterocyclic arsines

Metathesis of N-heterocyclic chloroarsines with sulfur-based nucleophiles furnished thio-substituted 1,3,2-diazarsolidines and 1,3,2-diazarsolenes. Crystallographic and NMR spectroscopic studies revealed that a thiocyanato-diazarsolene exhibits a salt-like structure composed of weakly interacting thiocyanate and arsenium ions, while the remaining products formed neutral molecules. The structural data indicate that the heterocyclic framework induces an elongation of exocyclic As-S bonds that is more prominent in diazarsolenes than in diazarsolidines and parallels the bond polarisation effect established for N-heterocyclic phosphines. The NMR data suggest that diazarsolenes undergo facile inversion of the pyramidal configuration at arsenic, which was successfully modelled by DFT studies.Peer reviewe

Diversity of occupants’ activity impact on indoor air

The problem of indoor air quality (IAQ) has attracted a great deal of attention recently. One of interesting aspects of this problem is the characterization of human impact on IAQ. This work presents a method which allows to determine the diversity of building occupants influence on indoor air. The method is based on the supervised clustering of the indoor air measurement data in domains of various indoor air parameters. The introduced approach was applied to examine the exemplary data set. The diversity of impact was studied in the domain of air parameters which characterize thermal conditions indoors and in the domain of chemical parameters of indoor air. The obtained results showed that the diversity of impact was greatly related to the fact that occupants’ activities occurred in combinations, rather than individually. It was also demonstrated that the diversity of impact was domain dependent. Most of examined activities showed greater diversity of influence in the domain of parameters which characterize thermal conditions. This shows that the activity-specific impacts would be rather associated with the domain of chemical parameters of indoor air. The proposed method allows to obtain information which can be useful in the diagnostics of IAQ and for the control of ventilation