Exclusive Hydrophobic Self-Assembly of Adaptive Solid-State Networks of Octasubstituted 9,9′-Spirobifluorenes

An easy and powerful access to 3,3′,6,6′-tetrasubstituted
9,9′-spirobifluorene derivatives with tetrahedral orientation
of the peripheral groups (i.e., −I, −CN, −NO2, −CHO, −COOH, −CCH,
−4-Py) was developed. The NMR and HRMS results are in agreement
with the proposed formula and the solid-state molecular structures
obtained by single-crystal X-ray diffraction. They form molecular
solids self-assembled via exclusive hydrophobic interactions. Solid-state
selection and adaptation can be obtained on the basis of variable
compact packing of functional groups present on the 9,9′-spirobifluorene
backbone.