Variable pore size, variable chemical functionality, and an example of reactivity within porous phenylacetylene silver salts

Investigations on molecular variants of the 3-fold symmetric 1,3,5-tris(4-e thynylbenzonitrile)benzene crystallized with silver triflate revealed a nea rly invariant pseudohexagonal porous structure type. Modifications involved the attachment of pendant groups to the central aromatic ring of the paren t molecule. Pendant groups include the vinyl group, stilbene, the chiral gr oup myrtanol, and groups with different chemical functionalities such as al cohols, ethers, and esters. Modifications also included the addition of elo ngated spacer units between the central benzene ring and the peripheral nit rile groups. In these molecules the acetylene bridges of 1,3,5-tris(4-ethyn ylbenzonitrile)benzene were replaced with diacetylene, ethynylbenzene, and diethynylbenzene type units. Single-crystal refinements for pentoxy-2,4,6-t ris(4-ethynylbenzonitril)benzene.AgOTf and 1,3,5-tris(4-(4-ethynylbenzonitr ile)phenyl)benzene.AgOTf as well as powder data on 12 crystalline phases sh owed the consistent formation of pseudohexagonal channels, demonstrating th at the parent porous architecture is stable both to functional modification of the interior of the channel as well as to enlargement of the pores. Pen toxy-2,4,6-tris(4-ethynylbenzonitrile)benzene.AgOTf refined in the monoclin ic space group Am. 1,3,5-Tris(4-(4-ethynylbenzonitrile)phenyl)benzene.AgOTf was found to be triclinic with space group P (1) over bar. These crystals have pseudohexagonal channels respectively 15 and 25 Angstrom in diameter. Cell constants based on powder data are compatible with channel diameters r anging from 10 to 30 Angstrom. The latter channel diameters are among the l argest known for organic porous solids. The introduction of the chiral myrt anol unit led to the preparation of a chiral porous solid. The thermal and chemical stabilities of these phases were investigated. The pseudohexagonal structure proved stable to complete solvent loss from the channel. It was found in the case of a host with alcohol functionality that an acid anhydri de guest, trifluoroacetic anhydride, reacted with the host to form an ester with retention of the porous structure type.