A stereogenic π-system based on dimer (2) and trimer (3) of [2.2]paracyclophane (PC) and biphenyl was prepared and its structural, photophysical, and chiroptical properties were investigated. X-ray analysis revealed that the quaterphenyl moieties in 2 adopt a double helical structure anchoring [2.2]PC from both sides. Furthermore, 3 forms a isosceles triangle structure with a large chiral cavity. A homodesmotic reaction using DFT calculations revealed that 2 has a larger strain energy than 3 owing to its highly twisted phenylene linkers. Electronic and circular dichroic (CD) spectra were recorded in CH 2 Cl 2 solution. The spectra of both 2 and 3 are similar, and their longest absorption band accompanying a remarkable Cotton effect is attributed to the transition from HOMO to LUMO, which is delocalized to the quaterphenyl moiety. These compounds exhibit fairly high fluorescence quantum yields (ϕ = 0.70-0.83) and moderate dissymmetry factor (j g CPL j = 1.6 × 10 À 3 ) in circularly polarized luminescence (CPL).
The Influence of alkyl chain length in quaternary ammonium cations on electrochemical Zn growth morphology in alkaline-based electrolytes was systematically investigated under constant current density. Mossy structures that typically developed at low current density were mitigated in an electrolyte with 1 mM octyltrimethylammonium chloride. By changing from octyl to decyl group in the surfactant, completely smooth deposition morphology was achieved.Electrochemical impedance spectroscopic analysis revealed that charge transfer resistance associated with Zn deposition increased with alkyl chain length. The obtained results indicate that bulky ammonium cations suppress excess electrodeposition due to the steric hindrance effect and thereby result in smooth morphology.
Difluoromethyl‐substituted allylic phosphates were synthesized from 2‐cycloalkenones through the addition of a (difluoromethyl)phosphonate and subsequent phospha‐Brook rearrangement. The obtained allylic phosphates were converted to the corresponding difluoromethyl‐substituted cycloalkenes using the Cu‐mediated SN2’ reaction of Grignard or organolithium reagents.magnified image
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