Coordinative self-assembly and solution-phase X-ray structural characterization of cavity-tailored porphyrin boxes.
Combining linear Zn porphyrin trimers with orthogonally derivatized porphyrin dimers leads rapidly and spontaneously to the formation of monodisperse, torsionally constrained boxes comprising six components and a total of 16 metalloporphyrins. In situ X-ray scattering measurements confirm the formation of monodisperse assemblies of precisely the size expected from model box structures. While simple subunits yield highly symmetrical boxes, we find that sterically demanding subunits produce unusual twisted boxes. Previous studies of porphyrin-based box-like assemblies (squares) for selective catalysis and molecular sieving revealed two function-inhibiting structural problems: torsional motion along the metal-porphyrin-metal axis and ambiguous outside versus inside functionalization (via axial ligation of available Zn(II) sites). The new 16-porphyrin box assemblies eliminate both problems.
Lee
Suk Joong
SJ
Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
Mulfort
Karen L
KL
Zuo
Xiaobing
X
Goshe
Andrew J
AJ
Wesson
Paul J
PJ
Nguyen
T SonBinh
TS
Hupp
Joseph T
JT
Tiede
David M
DM
D015394:Molecular Structure; D011166:Porphyrins / Q000737:chemistry*; D012996:Solutions; D014961:X-Ray Diffraction; D015032:Zinc / Q000737:chemistry*
D011166:Porphyrins; D012996:Solutions; D015032:Zinc