NanoPutians

NanoPutians are a series of “anthropomorphic” molecules designed and synthesized by Stephanie H. Chanteau and James M. Tour* at Rice University (Houston) in the early 2000s. As 2-D structural formulas, the molecules resemble human figures, with varying “hats” to distinguish them from each other. The project was intended to communicate organic synthesis and the nanoscale to the layperson.

Among the molecules prepared by the researchers were the NanoKid¹ (shown here), the NanoAthlete², the NanoPilgrim³, and the NanoGreenBeret⁴. The actual height of each is ≈2 nm. Each structure includes a 1,3-dioxolane head (the oxygen Os serve as the eyes) and benzene rings for the upper and lower bodies. The two bodies are connected by an alkyl or alkyne chain, depending on the desired “pose”; the arms are alkyne chains terminated by tert-butyl groups for the hands; and the legs are alkyne chains terminated by ethyl groups for the feet.

NanoKid was the first NanoPutian synthesized by Chanteau and Tour. They made the upper body in a five-step sequence beginning with p-dibromobenzene. The seven-step lower-body synthesis began with 4-nitroaniline. The two components were attached via a coupling reaction between an iodobenzene functionality on the upper body and an ethynyl group on the lower. The other three figures cited above were made by modifying the NanoKid head.

Because the NanoPutians were created as instructional tools, no properties or hazard information has been reported for them, other than spectroscopic data.

In 2017, Takeo Sakai and colleagues at Meijo University (Nagoya, Japan) reported a new wrinkle on NanoKid chemistry. They synthesized a molecule that had a cyclopentadienide body with cyano groups for arms and legs and a 1,3-dioxane head. Its pyridinium salt, which they named NanoGoblin, catalyzed the methanolysis of acetals, which the authors demonstrated by “biting” the head off NanoKid and replacing it with a dimethylacetal group.

1. SciFinderⁿ name: 1,3-dioxolane, 2-{2,5-bis(3,3-dimethyl-1-butyn-1-yl)-4-[2-(3,5-di-1-pentyn-1-ylphenyl)ethynyl]phenyl}-.
2. CAS Reg. No. 618904-88-4.
3. CAS Reg. No. 618904-89-5.
4. CAS Reg. No. 618904-91-9.