Synthesis and Photoisomerization of Substituted Dibenzofulvene Molecular Rotors

Everhart, Stephanie C.; Jayasundara, Udaya K.; Kim, HyunJong; Procúpez‐Schtirbu, Rolando; Stanbery, W.; Mishler, Clay H.; Frost, Brian J.; Cline, Joseph I.; Bell, Thomas W.

doi:10.1002/chem.201600854

Cited by 12 publications

(21 citation statements)

References 108 publications

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“…The dibenzofulvene motors, in turn, lack a stereocenter but incorporate an axially chiral trityl moiety. Designed and synthesized by Bell and co‐workers, these systems appear promising motor candidates because their Z / E photoisomerizations around the central double bond are unidirectional and can attain high quantum yields (QYs) by appropriate substitutions (X in motor 4 ).…”

Section: Rotary Molecular Motorsmentioning

confidence: 99%

Quantum chemical design of rotary molecular motors

Oruganti

Wang

Durbeej

2017

Int J of Quantum Chemistry

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This tutorial review describes how recent quantum chemical calculations and non-adiabatic molecular dynamics simulations have provided valuable guidelines and insights for the design of more powerful synthetic rotary molecular motors. Following a brief overview of the various types of rotary motors synthesized to date, we present computationally identified steric and electronic approaches to significantly reduce the free-energy barriers of the critical thermal isomerization steps of chiral overcrowded alkenes, a main class of motors whose potential for many different kinds of applications is well documented. Furthermore, we describe how computational research in this field has provided new motor designs that differ from overcrowded alkenes by either (1) completing a full 3608 rotation through fewer steps, (2) exhibiting more efficient photochemical steps, or (3) requiring fewer chiral features for their function, including a design that even in the absence of a stereocenter achieves unidirectional rotary motion from two Z/E photoisomerizations alone.chirality, molecular motors, non-adiabatic molecular dynamics, photoisomerization, steric interactions | I N TR ODU C TI ONIn this tutorial review, we give an account of how quantum chemical research has contributed to advance the field of artificial molecular machines.This field [1][2][3][4][5][6][7][8][9][10][11] is devoted to the fabrication of molecular systems capable of performing the same type of machine-like functions that Nature-made protein complexes carry out in order to, among other things, propel cells, store energy in cells, equip cells with transport systems, and generate biomechanical forces. [12][13][14] Although artificial molecular machines are yet to make an impact on our everyday lives, the field is currently undergoing a rapid expansion both in terms of what man-made molecules can accomplish and the areas of expertise of the scientists drawn to the field. In many ways, this development, envisioned already in 1959 by Richard Feynman in his prophetic "There's Plenty of Room at the Bottom" lecture, [15] is testament to the groundbreaking work on the design and synthesis of molecular machines [16][17][18][19][20][21][22][23][24][25] for which Jean-Pierre Sauvage, Sir J. Fraser Stoddart and Bernard (Ben) L. Feringa were awarded the Nobel Prize in Chemistry 2016.While a molecular machine can be defined as "an assembly of a discrete number of molecular components designed to perform mechanical-like movements (output) as a consequence of appropriate external stimuli (input)," [2] this tutorial review focuses on the subset of such systems known as molecular motors. Loosely speaking, molecular motors are molecules that can produce net work by absorbing external energy and converting the energy into directed (non-random) mechanical motion in a controllable fashion. The ability to produce net work is the distinguishing feature of molecular motors vis-a-vis molecular switches, the latter of which sustain back-and-forth motion but not the continuous m...

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Section: Rotary Molecular Motorsmentioning

confidence: 99%

Quantum chemical design of rotary molecular motors

Oruganti

Wang

Durbeej

2017

Int J of Quantum Chemistry

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“…7,9 In two recent studies, however, it has been demonstrated that permanent point chirality is not an absolute requirement for achieving unidirectional rotary motion by an overcrowded alkene-based motor that exhibits a chiral-like feature in the form of a pseudo-asymmetric carbon, 16 or incorporates an axially chiral trityl moiety. 17 Interestingly, unidirectional rotary motion has also been realized or conceived for systems that contain a plane of symmetry, either by exploiting mechanically interlocked architectures 18 or using polarized laser pulses 19,20 or oscillating electric fields 21 as the input energy source.…”

mentioning

confidence: 99%

Light-driven rotary molecular motors without point chirality: a minimal design

Wang

Oruganti

Durbeej

2017

Phys. Chem. Chem. Phys.

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A fundamental requirement for achieving photoinduced unidirectional rotary motion about an olefinic bond in a molecular motor is that the potential energy surface of the excited state is asymmetric with respect to clockwise and counterclockwise rotations. In most available light-driven rotary molecular motors, such asymmetry is guaranteed by the presence of a stereocenter. Here, we present non-adiabatic molecular dynamics simulations based on multiconfigurational quantum chemistry to demonstrate that this chiral feature is not essential for inducing unidirectional rotary motion in molecules that incorporate a cyclohexenylidene moiety into a protonated Schiff-base framework. Rather, the simulations show that it is possible to exploit the intrinsic asymmetry of the puckered cyclohexenylidene to control the direction of photoinduced rotation.

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“…According to previous studies, polar substituents at the 2‐position of TEF greatly increase average φ ZE / φ EZ values. They increase in the order t Bu (TTEF, 0.04), NO 2 (NTEF, 0.26), CN (CTEF, 0.39) and I (ITEF, 0.50) . The current studies add quantum yields for four additional polar substituents to this list: NH 2 (ATEF, 0.006), NMe 2 (DTEF, 0.009), NH 3 + (ATEF⋅H + , 0.20), and NMe 2 H + (DTEF⋅H + , 0.25).…”

Section: Figurementioning

confidence: 98%

“…The synthesis of ATEF was described previously and the new analog DTEF was prepared as shown in Scheme . Starting material 1 was prepared by methylation of 2‐aminofluorene with paraformaldehyde and sodium cyanoborohydride in acetic acid .…”

Section: Figurementioning

confidence: 99%

Proton‐Gated Photoisomerization of Amino‐Substituted Dibenzofulvene Rotors

et al. 2016

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Derivatives of 9-(2,2,2-triphenylethylidene)-fluorene (TEF) undergo E/Z photoisomerization and are candidates for light-powered molecular actuators and switches. The 2-substituted derivatives bearing an amino group (ATEF) or a dimethylamino group (DTEF) are weakly photoactive in the absence of acids, but protonation increases photoisomerization quantum yields by factors of 30-60. Such compounds may be useful for incorporation into pH-switchable photoactive devices.

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Synthesis and Photoisomerization of Substituted Dibenzofulvene Molecular Rotors

Cited by 12 publications

References 108 publications

Quantum chemical design of rotary molecular motors

Quantum chemical design of rotary molecular motors

Light-driven rotary molecular motors without point chirality: a minimal design

Proton‐Gated Photoisomerization of Amino‐Substituted Dibenzofulvene Rotors

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