Host–guest chemistry. Methanol, ethanol and propan‐1‐ol inclusion compounds of 2‐[o‐(triphenylphosphoranylidenamino) benzyliden] amino‐1H‐2, 3‐dihydroindazol‐3‐one. X‐ray structural characterization of the free host and its ethanol inclusion compound

The title compound (3) which is a 2‐aminoindazol‐3‐one derivative linked through a methinephenyl bridge to an iminophosphorane, and unrelated to any previous host, is described. The bulky triphenylphosphino group provides the cavity and the indazol‐3‐one the hydrogen bonds (both donor NH and acceptor CO). X‐ray structural analyses of the free host 3 and that of its ethanol inclusion compound 3 · EtOH are reported. Hydrogen bonds resulting in infinite chains dominate the molecular packing. The use of thermal analysis and 13 C CP/MAS NMR shed light in the structures of two other inclusion compounds, 3 · MeOH and 3 PrOH. The conclusion is that all three compounds are similar. An analysis of the cavities, using a model of interpenetrating spheres of van der Waals radii, demonstrates that in the case of the ethanol derivative, the cavity has the space and form requirements necessary to include the propanol guest.