in neat (no solvent) byproducts: H2; addn. of the pyrazole to KBH4, mixt. slowly heated to 110°C, whenevolution of H2 subsided, temp. raised to 190°C, heated until H2 evolution had ceased; toluene added, soln. concd., hexane added, crystn. at 0°C, crystals washed with hexane at 0°C, sublimation;

in toluene simultaneous preparation at 60 ° C;;

in toluene react. performed under an atmosphere of pure dinitrogen, mixt. of Mo2O3{S2P(OMe)2}4 (2.0 mmol) and Ph3P (0.525 g, 2.0 mmol) refluxed in toluene (50 ml) for 1h, addn. of K{HB(Me2pz)3} (1.48 g, 4.4 mmol) to cooled mixt., refluxed for 4h;; filtration in air, solvent removed in vacuo, column chromatography (SiO2/CH2Cl2), recrystn. from CH2Cl2; elem. anal.;;