A reactivity model for concerted cycloaddition reactions is presented which allows a systematization of substituent effects. The treatment is based on the frontier electron theory of Fukui. The consideration of the energy separations of HOMOs (Highest Occupied Molecular Orbitals) and LUMOs (Lowest Unoccupied Molecular Orbitals) leads to three reactivity types in these cycloadditions. For the Di...

The central component of the programmable molecular switch recently demonstrated by Stoddart and Heath is [2]rotaxane, which consists of a cyclobis(paraquat-p-phenylene) shuttle (CBPQT(4+))(PF(6)(-))(4) (the ring) encircling a finger and moving between two stations, tetrathiafulvalene (TTF) and 1,5-dioxynaphthalene (DNP). As a step toward understanding the mechanism of this switch, we report he...

Setting up spatially separated HOMO and LUMO regions in a non-Kekulé structured trinuclear Ir(III)-Ru(II)-Ir(III) system and using oxidative-reduction electrochemiluminescence leads to emissions that are not detected in photoluminescence. Moreover, the new design allows tuning of the wavelength of emission in a stepless fashion as a function of the selected potential range.

A recent improvement in the design of dyesensitized solar cells has been the combination of lightabsorbing, electron-donating, and electron-withdrawing groups within the same sensitizer molecule. This dye architecture has proven to increase the energy conversion efficiency of the cells, leading to record efficiency values. Here we investigate a zinc(II)-porphyrin-based dye with triphenylamine d...

Bei Betrachtung der geometrischen und elektronischen Struktur des Tris(pentafluorethyl)silanids erscheint das Anion auf den ersten Blick als Lewis-Base. Quantenmechanischen Rechnungen zufolge liegen die HOMO- LUMO-Energien von Perfluoralkylsilaniden deutlich niedriger nicht fluorierter Derivate. Dies hat eine geringere Lewis-Basizität zugleich erhöhte Lewis-Acidität [Si(C2F5)3]−-Ions zur Folge....

Abstract The highest occupied molecular orbital (HOMO) and lowest unoccupied (LUMO) energies, which are key factors in optoelectronic devices, must be accurately estimated for newly designed materials. Here, we developed a deep learning (DL) model that was trained with an experimental database containing the HOMO LUMO energies of 3026 organic molecules solvents or solids capable predicting mean...

Novel bisimide-fused acenes were synthesized via bismuth triflate mediated double-cyclization reaction of acid chlorides and isocyanates. Their optical and electrical properties revealed significantly smaller HOMO-LUMO gaps compared with those of their parent acenes. Fabricated OFET based on tetracene bisimide showed n-type OFET outputs.

Two new stable Volleyballenes, the Y20C60 and La20C60 molecular clusters, are proposed on the basis of first-principles density functional theory. In conjunction with recent findings for the scandium system, these findings establish Volleyballene M20C60 molecules as a general class of stable molecules within the fullerene family. Both Y20C60 and La20C60 molecules have Th point group symmetries ...

This paper discusses the fundamental features of the dielectric-dependent screened exchange potential approach for organic molecules and photocell materials. The energy difference (gap) between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) is a key factor when designing organic photocell materials. The magnitude of this energy gap strongly depe...