Modulation of hydrophilicity inside the cavity of molecular rectangles self-assembled under ambient conditions.

Three novel molecular rectangles of tetranuclear Cu(ii) with a variation in the flexible methylene chain length on the two opposite sides have been synthesized from a one pot self-assembly reaction in a methanol-water mixture under ambient conditions. Their solid state molecular structures are determined by single crystal X-ray diffractometry, while their structural integrity in the solution state is confirmed by electrospray mass spectrometry. With such a subtle variation, modulation of hydrophilicity inside the cavity of these molecular rectangles is achieved as evident from the water and methanol vapor sorption studies.