| Summary: | Our group has been synthesizing porous supramolecular metal-organic molecules using
multidentate β-diketones as ligands. For example, m-phenylenebis(acetylacetone) (m-pbaH2, 1)
and m-phenylenebis(dipropionylmethane) (m-pbprH2, 2) were readily converted to the molecular
squares Cu4(m-pba)4 (6) and Cu4(m-pbpr)4 (7), which bind guests such as 4,4-bpy and C60.1
However, 6 and 7 are only soluble in a few solvents, limiting their use in practical applications.
It is therefore necessary to derivatize the ligand with different functional groups in order to
improve solubility and adjust host-guest properties. Simple alkoxy derivatives should prove
useful in testing this idea as they would be relatively chemically inert and should not interfere
with reactions in their synthesis. Herein, I report synthesis of the ligands 5-MeO-m-pbaH2 (3), 5-
BuO-m-pbaH2 (4), and 2-MeO-m-pbaH2 (5). Ligand 3 was synthesized from 5-methoxy-1,3-
benzendimethanol in a two step reaction and reacted with Cu2+ to form a complex that is soluble
in CH2Cl2 and THF. X-ray analysis of this complex confirms that it is a molecular square with
the formula Cu4(5-MeO-m-pba)4 (square 8). Ligand 4 was synthesized from dimethyl 5-
hydroxyisophthalate in a three step reaction and used for the synthesis of Cu4(5-BuO-m-pba)4
(square 9). Square 9 is soluble in a wide range of solvents including CH2Cl2, CHCl3, THF, and
several benzene derivatives. Ligand 5 was synthesized from 2-methoxyisophthalic acid in a
three step reaction and used for the synthesis of Cu4(2-MeO-m-pba)4 (square 10).
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