Aqua{5,15-bis[4-(2-trimethylsilylacetylene)phenyl]-2,8,12,18-tetrakis(2-methoxycarbonylethyl)-3,7,13,17-tetramethyl-10,20-dioxoporphyrinato}zinc(II)

Andrew D. Bond, Neil Feeder, Simon J. Teat, Zoe Clyde-Watson, Nick Bampos and Jeremy K.M. Sanders, Acta Cryst. (2001). E57, m454–m456

A group from the Cambridge Centre for Molecular Recognition and CLRC Daresbury Laboratory reported the structure of a trans-zinc dioxoporphyrin with the other two meso positions occupied by the electron-withdrawing group 4-(2-trimethylsilylacetylene). There is a molecule of water occupying an axial site that hydrogen bonds to the carbonyl oxygen of a 2-methoxycarbonylethyl side chain of another molecule to form a centrosymmetric dimer (see figure). The porphyrin adopts a saddle conformation. Adjacent dimers are stacked via laterally shifted porphyrin planes with a Zn…Zn1´ distance of 5.719(1) Å. In adjacent molecules there are edge-to-face interactions. This large structure has 80 non-hydrogen atoms in the asymmetric unit. A small crystal of dimensions 0.02 × 0.06 × 0.07 mm was used to collect a data set at Station 9.8, Daresbury SRS. The radiation employed had λ = 0.6879 Å. An excellent solution and refinement was obtained, illustrating the utility of synchrotron radiation in such instances.

Reviewed by Marilyn Olmstead, U. of California, Davis, USA