New sterically hindered phenyl mesityl pyrazoline cpds. - are used as scintillator having large strokes shift, good quantum yield and decay time

摘要

New sterically hindered 1-phenyl-3-mesityl-2-pyrazoline derivs. (I) are of the formula (I) where R1 = electron donor substit.; and R2 = Me, OMe or H. The prepn. of (I) is claimed whereby mesityl vinyl ketone (II) is reacted with a phenylhydrazine deriv. of formula (III). USE/ADVANTAGE - (I) are claimed for use as scintillators. They are useful in large chambers or in polymer scintillation fibres. Their fluoroescence emission and absorption wavelengths are further apart than usual, so that overlap occurs only at very high (I) concns. in soln. The fluorescence quantum yield and decay time are in the favourable ranges of known derivs.