These IPPs are really having bad sense of Grammar. For instance ippsRealToCplx_32f should mean it converts real numbers to complex whereas it does just the opposite - it is converting Complex to real. Just nuts !! what say ?
>>...How to deinterlace complex from real data...
There are two functions in DSP domain of IPP and here are short descriptions from ipps.h header file:
ippsCplxToReal - form the real and imaginary parts of the input complex vector
ippsRealToCplx - form complex vector from the real and imaginary components
and, as you can see, ippsRealToCplx needs to be used in your case.