  Based on quantum complementary relations (QCRs) and a purification scenario,
we analyze a class of N-qubit mixed states that are entangled but do not have
two-, and genuine three-, four-, ..., N-qubit entanglements. It is shown that
entanglement (one-tangle or negativity) in these mixed states is closely
related to the QCR entanglement of their purified states. In particular, it is
elaborated that when the mixed state does not have multipartite tangles (two-
and higher tangles), its entanglement is actually a kind of genuine
multipartite QCR entanglement between the system and its environment.
