Unique interplay between electronic states and dihedral angle for the molecular rotor diphenyldiacetylene

Thulstrup, Peter W.; Hoffmann, Søren Vrønning; Hansen, Bjarke Knud Vilster; Spanget‐Larsen, Jens

doi:10.1039/c0cp02914a

Cited by 33 publications

(44 citation statements)

References 51 publications

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“…60 Calculations have indicated that the barrier for diphenyldiacetylene (DPDA, Ph-C≡C-C≡C-Ph) is around 1.1 kJ mol −1 (PBE1PBE/6-31+G*//6-31G* and B3LYP/6-31+G**). 61,62 1,4-Bis(phenylethynyl)benzene (Ph-C≡C-C 6 H 4 -C≡C-Ph) has an experimental barrier of 2.75 kJ mol −1 , similar to that for tolane, but DFT (B3LYP/6-31G**) dramatically overestimates the barrier at 8.75 kJ mol −1 . 63 To ensure comparability of computational results, we have calculated the torsion barrier of tolane and DPDA at the B3LYP/6-31G* level of theory, by performing constrained geometry optimisations of planar and perpendicular conformers.…”

Section: Evidence For Enhanced Conjugation In the Planar Conformer From C≡c Bond Length And Vibrational Frequenciesmentioning

confidence: 94%

Experimental and computational evaluation of the barrier to torsional rotation in a butadiyne-linked porphyrin dimer

Peeks

Neuhaus

Anderson

2016

Phys. Chem. Chem. Phys.

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The barrier to torsional rotation in a butadiyne-linked porphyrin dimer has been determined in solution using variable temperature UV-vis-NIR spectroscopy: ΔH = 5.27 ± 0.03 kJ mol(-1), ΔS = 10.69 ± 0.14 J K(-1) mol(-1). The value of ΔH agrees well with theoretical predictions. Quantum chemical calculations (DFT) were used to predict the torsion angle dependence of the absorption spectrum, and to calculate the vibronic fine structure of the S0 → S1 absorption for the planar dimer, showing that the absorption band of the planar conformer has a vibronic component overlapping with the 〈0|0〉 absorption of the perpendicular conformer. The torsion barrier in the porphyrin dimer is higher than that of 1,4-diphenylbutadiyne (calculated ΔH = 1.1 kJ mol(-1)). Crystallographic bond lengths and IR vibrational frequencies confirm that there is a greater contribution of the cumulenic resonance form in butadiyne-linked porphyrin dimers than in 1,4-diphenylbutadiyne. The DFT frontier orbitals of the twisted conformer of the porphyrin dimer are helical, when calculated in the absence of symmetry. The helical character of these orbitals disappears when D2d symmetry is enforced in the 90° twisted conformer. Helical representations of the frontier orbitals can be generated by linear combinations of the more localised orbitals from a symmetry-constrained calculation but they do not indicate π-conjugation. This work provides insights into the relationship between electronic structure and conformation in alkyne-linked conjugated oligomers.

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Section: Evidence For Enhanced Conjugation In the Planar Conformer From C≡c Bond Length And Vibrational Frequenciesmentioning

confidence: 94%

Experimental and computational evaluation of the barrier to torsional rotation in a butadiyne-linked porphyrin dimer

Peeks

Neuhaus

Anderson

2016

Phys. Chem. Chem. Phys.

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“…SRLD spectra were measured at room temperature as previously described [29][30][31][32][33] on the CD1 beamline [27,28] at the storage ring ASTRID at the Centre for Storage Ring Facilities (ISA). Two absorbance curves were recorded with the electric vector of the sample beam parallel and perpendicular to the stretching direction of the PE polymer.…”

Section: Linear Dichroism (Ld) Spectroscopymentioning

confidence: 99%

“…Secondly, the use of synchrotron radiation [27,28] enables a substantial expansion of the investigated spectral range, compared with the use of a traditional light source [29][30][31][32][33]. In the present investigation, the measurement is thus extended into the vacuum UV, covering the region up to 58000 cm -1 (170 nm).…”

Section: Introductionmentioning

confidence: 99%

Electronic states of dibenzo-p-dioxin. A synchrotron radiation linear dichroism investigation

et al. 2019

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Electronic states of dibenzo-p-dioxin. A synchrotron radiation lineardichroism Investigation.

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“…2.46 kJmol −1 ),, and 3) the sp ‐ sp bond between two ethynyl groups ( ca . 1.12 kJmol −1 ) ,. As a result of the relatively low rotation barriers of the sp ‐ sp 2 bonds and, particularly, the sp ‐ sp diacetylene bond, compound 2 exchanges dynamically in solution between 4 main types of similarly populated π‐conjugated conformations, obtained by fast 90° rotation of any of these bonds.…”

Section: Figurementioning

confidence: 99%

Self‐Assembly of Diacetylene‐Bridged Phenylenevinylene Oligomers in Water and Organic Solvents

et al. 2019

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Rodlike π‐conjugated molecules in which two OPV fragments are connected through a diacetylene bond self‐assemble in aqueous and organic media. Optical spectroscopy and AFM measurements indicated that, in water, strong hydrophobic interactions between π‐cores promote aggregation into robust, uniform micellar structures. In contrast, in apolar solvents, a fibrilar morphology is obtained by coiling of columnar stacks. These stacks are formed in a nucleation‐elongation process with degrees of cooperativity of 0.006, that is influenced by the low rotation barriers around the σ‐bonds in the diacetylene linker.

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Unique interplay between electronic states and dihedral angle for the molecular rotor diphenyldiacetylene

Cited by 33 publications

References 51 publications

Experimental and computational evaluation of the barrier to torsional rotation in a butadiyne-linked porphyrin dimer

Experimental and computational evaluation of the barrier to torsional rotation in a butadiyne-linked porphyrin dimer

Electronic states of dibenzo-p-dioxin. A synchrotron radiation linear dichroism investigation

Self‐Assembly of Diacetylene‐Bridged Phenylenevinylene Oligomers in Water and Organic Solvents

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