Oxaphosphacyclophanes Constructed from a Bis(triphenylphosphine oxide) Moiety Linked by Dioxyalkyl Chains: Synthesis and Crystal Structures

Oxaphosphacyclophanes,
a bis­(triphenylphosphine oxide) moiety linked
by dioxypropane, dioxybutane, dioxypentane, and dioxyhexane, were
synthesized from the reaction of bis­(4-hydroxyphenyl)­phenylphosphine
oxide and dibromoalkanes. Single-crystal X-ray diffraction analysis
and exploring intermolecular interactions by using the Hirshfeld surface
revealed that the butylene-linked oxaphosphacyclophane (2) had a one-dimensional (1D) supramolecular structure via CH/π
interactions between the terminal phenyl group of 2 and
a phenylene group of the cavities. In the packing diagram of pentylene-linked
oxaphosphacyclophane (3) with antiform, one macrocycle
recognized two terminal phenyl groups to form a 1D supramolecular
chain via π/π interactions. The syn-form of 3 was obtained by the recrystallization from toluene and CHCl3. In this crystal, a toluene molecule avoid construction of
a 1D chain. The antiform of hexylene-linked oxaphosphacyclophane 4 was obtained by the recrystallization from cyclohexane and
CHCl3. Cyclohexane was captured in the cavity via CH/π
interactions. Two molecules of 4 with the syn-form recognized
each other to construct a dimeric structure via CH/π interactions.