A Singular Molecule-to-Molecule Transformation on Video: The Bottom-Up Synthesis of Fullerene C₆₀ from Truxene Derivative C₆₀H₃₀

Abstract

Singular reaction events of small molecules and their dynamics remain a hardly understood territory in chemical sciences since spectroscopy relies on ensemble-averaged data, and microscopic scanning probe techniques show snapshots of frozen scenes. Herein, we report on continuous high-resolution transmission electron microscopic video imaging of the electron-beam-induced bottom-up synthesis of fullerene C 60 through cyclodehydrogenation of tailor-made truxene derivative 1 (C 60 H 30 ), which was deposited on graphene as substrate. During the reaction, C 60 H 30 transformed in a multistep process to fullerene C 60 . Hereby, the precursor, metastable intermediates, and the product were identified by correlations with electron dose-corrected molecular simulations and singlemolecule statistical analysis, which were substantiated with extensive density functional theory calculations. Our observations revealed that the initial cyclodehydrogenation pathway leads to thermodynamically favored intermediates through seemingly classical organic reaction mechanisms. However, dynamic interactions of the intermediates with the substrate render graphene as a non-innocent participant in the dehydrogenation process, which leads to a deviation from the classical reaction pathway. Our precise visual comprehension of the dynamic transformation implies that the outcome of electron-beam-initiated reactions can be controlled with careful molecular precursor design, which is important for the development and design of materials by electron beam lithography.

Time-Resolved Imaging of Stochastic Cascade Reactions over a Submillisecond to Second Time Range at the Angstrom Level

“…Nonetheless, the analysis becomes possible if the method continuously monitors individual molecules and their reactions. − We recently reported the cinematographic study of converting a C 60 H 30 molecule into fullerene C 60 at 2–25 frames per second (fps) over tens of seconds, using single-molecule atomic-resolution time-resolved electron microscopy (SMART-EM). − In this work, we studied the cascade dimerization of single vdW dimers of C 60 using a direct electron detector (DED) camera operating at 1600 fps, which expanded the analytical time range of the study by a factor of 10 5 . Through the use of a Chambolle total variation (CTV) denoising algorithm, a method widely employed for the denoising of optical digital images, − and automated cross-correlation (XC) image matching analysis of density functional theory (DFT)-based TEM-simulations, , we report here the experimental identification of OT-0 , 1 , 2 , 4 , 11 , and 14 intermediates, which were distinguished by their shape and size, and we could resolve the lifetime of individual intermediates under our standard TEM conditions. The reaction events were purely stochastic, and the lifetime of each metastable intermediate also changed stochastically.…”

Atomic-number ( Z )-correlated atomic sizes for deciphering electron microscopic molecular images

“…Utilizing specimens attached to a substrate or those comprising a part of a large crystal, the conventional TEM technique has suffered from similar limitations. AR-TEM imaging of single molecules in or on a carbon nanotube (CNT) ( 10 ) or on graphene ( 21 , 22 ) has realized dynamic molecular imaging against a vacuum background, hence opening an avenue to single-molecule atomic-resolution time-resolved electron microscopic (SMART-EM) imaging ( 23 ). Here, we can study the time evolution of structural changes and reactions with up to millisecond speed and sub-Å spatial resolution ( 18 ).…”

Time-Resolved Atomistic Imaging and Statistical Analysis of Daptomycin Oligomers with and without Calcium Ions

“…The agreement endorses the validity of our “marine census” strategy to obtain statistical and atomistic structural information on the intermediates and reactive species present in the solution. Recent reports on the in situ cinematographic recording of fast chemical events, ,, and ex situ imaging of intermediates of metal–organic framework formation, metal catalysis, and crystal formation suggest the beginning of an era of cinematic chemistry in research and education.…”