Cis/Trans isomerization and conformational properties of 2,4-bis(primary amino)-1,3,2,4-diazadiphosphetidines

Alkyl substituted 1,3,2, 4-diazadiphosphetidines are prepared from RNH2/PCl3 in a medium of petroleum ethers. Cis isomer is favored, as the bulk of the alkyl substituent is increased. The temperature dependent 3' PNMR spectra reveals that transdiazadiphosphetidines are temperature-independent up to 90 degrees Celsius. Rotational barriers around the exo P-N bands are more for cis isomers than for trans isomers.