ABSTRACT
The data presented in this article are related to the research article entitled "An unconventional helical push-pull system for solar cells" (Dova et al., 2019). This article provides: a) the cyclic voltammogram plots in solution of helical push-pull sensitizers and the corresponding precursors; b) the visualization of the leading natural transition orbital (NTO) pairs obtained by theoretical calculation of frontiers orbitals; c) J/V curves of dye-sensitized solar cells (DSSC) sensitized by the dyes, without 3a,7a-dihydroxy-5b-cholic acid (CDCA) as co-adsorbent agent; d) 1H and 13C NMR spectra of dyes.
ABSTRACT
A one-pot, multicomponent strategy was used to synthesize the first example of the dirhenium carbonyl coordination complex 2, in which the two metal atoms are connected through a chiral helical-shaped diphosphine oxide. Thanks to the flexibility of the helix of helicene 1, complex 2 was isolated in quite a good yield as a stable compound. It was characterized by analytical and spectroscopic techniques as well as by single-crystal X-ray analysis, which confirmed the chemical structure and the peculiar architecture of 2. In addition, computational studies were in agreement with the transitions observed in the experimental UV-vis spectrum, revealing the presence of two bands with maxima at about 520 (metal-to-ligand charge transfer) and 400 nm (IL).
ABSTRACT
Substituted phosphathiahelicenes have been prepared via a straightforward two-step procedure involving the regioselective bromination of a preformed helical scaffold, followed by palladium catalyzed coupling reactions. The new helicenes have been used as ligands in gold(i)-catalyzed [4+2] cyclizations of 1,6-enynes. The resulting dihydro-cyclopenta[b]naphthalene derivative was obtained in excellent yields and with up to 91% ee.
ABSTRACT
Chiral helical-based phosphanes are challenging and promising ligands, with a great potential for the generation of both organic and organometallic catalysts. We report here the preparation of novel chiral thiahelicene-based alkyl phosphanes, isolated and characterized as air-stable borane adducts, and the investigation of their experimental and theoretical (chir)optical properties. X-ray characterization of a mono- and a disubstituted derivative as a racemic mixture has been performed, which confirms the influence of the number and nature of substituents on the flexibility of the helix. In addition, the absolute configuration inferred from CD spectra of the two enantiomers of a diborane complex has been established from X-ray analysis. State-of-the-art quantum chemical calculations of vibrationally resolved spectra allow, for the first time, for an unambiguous assignment of the experimentally observed peaks in linear absorption and circular dichroism spectra to excited electronic states of this class of thiahelicene phosphorus derivatives.
ABSTRACT
A novel nanoconstruct based on poly(lactic-co-glycolic acid) nanoparticles loaded with a tetrathiahelicene molecule conjugated to a fluorescent rhodamine probe was prepared and characterized. Because helicenes are known to be very promising DNA intercalators, the tetrathiahelicene was selected for this study as a model therapeutic cytotoxic molecule. The ability of the nanoconstruct to internalize the tetrathiahelicene and deliver it intracellularly in a safe manner has been investigated by means of cytotoxicity and cell uptake tests on Balb/3T3 cloneâ A31 fibroblasts. The outcomes of this study suggest the suitability of the developed nanoconstruct to act as a vector for the intracellular delivery of hydrophobic small molecules, such as helicenes, thus contributing to their possible future exploitation as novel therapeutics.
ABSTRACT
Enantiomerically pure thiahelicenes displaying a terminal phosphole unit and a stereogenic phosphorus center have been prepared by oxidative photocyclization of a diaryl-olefin precursor. Starting from one of these phosphathiahelicene oxides, the corresponding trivalent phosphine-Au(I) complex is obtained with complete diastereoselectivity. It affords a new, excellent precatalyst for the enantioselective cycloisomerization of N-tethered enynes (up to 96 % ee).
ABSTRACT
New tetrathia[7]helicene-based (7-TH-based) gold(I) complexes 6 and 7 have been readily prepared by reaction of the respective phosphine ligands 2 and 3 with Au(tht)Cl in a 1:1 and 1:2 molar ratio, respectively. These complexes have been fully characterized by analytical and spectroscopic techniques as well as quantum chemical calculations. The molecular structure of dinuclear complex 7 has been determined by single-crystal X-ray diffraction, showing a gold-gold interaction of 3.1825(3) Å and a significant contraction of the 7-TH total dihedral angle. Au(I) complex 7 displays luminescence emission at room and low temperature in diluted solution and in the solid state. Quantum chemical calculations show that the luminescence emission at room temperature is primarily due to slightly perturbed fluorescence emission from purely ππ* excited states of the conjugated helicene scaffold. At 77 K phosphorescence emission is displayed as well. Preliminary studies on the use of 6 and 7 as catalysts in typical Au(I)-catalyzed cycloisomerizations have demonstrated the reactivity of these systems in the intramolecular allene hydroarylations and the hydroxycarboxylation of allene-carboxylates.
