Related Experiment Video
Updated: Sep 2, 2026

Synthesis and Characterization of Supramolecular Colloids
Published on: April 22, 2016
Colloidal Crystals Engineered with DNA and Perylenediimide Exhibit Symmetry-Breaking Charge Transfer
Cuizheng Zhang1, Yi Xie1, Georgia C Mantel1
1Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois60208, United States.
Abstract:
Perylenediimide (PDI) and its derivatives are widely studied for their photophysical and photochemical properties, making them promising candidates for photonic materials, organic semiconductors, and molecular qubits. However, the lack of control over their aggregation pathways and charge-transfer coupling severely limits their uses. Here, we report the synthesis of PDI-DNA bioconjugates as a new class of "programmable atom equivalents" (PAEs), in which a single PDI core is covalently linked to two DNA strands. Unlike conventional PAE superlattices formed by slow thermal annealing, the vapor-diffusion crystallization method enables the colloidal crystallization of PDI-DNA conjugates into large single-crystalline superlattices through cooperative DNA hybridization and PDI π-π stacking. The peripheral four sticky ends hybridize into a DNA framework, which serves as a scaffold, organizing the PDI cores into well-defined dimers, rather than disordered aggregates or micelles. The dimeric building units are rigid yet highly dynamic due to the intrinsic flexibility of the linkers, yielding superlattices with programmable PDI packing geometries and adaptiveness upon structural modifications. For most PDI crystals, PDI units stack continuously in one dimension to maximize interactions, which tend to hinder charge separation. Here, DNA not only encodes sequence-specific interactions but also sterically and electrostatically isolates PDI dimers as discrete photonic units into solid-state optically active materials. The structural tunability of the system can be readily adjusted by varying the PDI core or the linker length between the PDI core and the DNA shell. Notably, these superlattices exhibit photoinduced symmetry-breaking charge transfer distinct from that of monomers or micellar aggregates.
Related Concept Videos
Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...

