USE IF Function in Ecel for Time

Hi Guys

i want to read the Time (in 24h Formatting) out of a cell (Example = 12:25:36) 

I want to check if the Time is betw. 23:00 and 07:00. if so write NIGHT and if not DAY

i use 

=WENN(UND(D2>WERT("07:00");D2<WERT("23:00"));2;"NIGHT")

in some Cell's i see 00:00:00 in some Night... what i did wrong?