Preparation and Properties of Fluorenylidene(phenyl)phosphines Bearing Bulky Groups with Electron-Donating Substituents in the Ortho Position on the Phenyl Group
Fluorenylidene(phenyl)phosphines having bulky substituents with an electron-donating group in the o-position on the phenyl group were prepared and their properties were compared. The prepared materials included 2,4-di-t-butyl-6-methoxyphenyl, 2,4-di-t-butyl-6-(phenoxymethyl)phenyl, 2,4-di-t-butyl-6-(dimethylamino)phenyl, or 2,4-di-t-butyl-6-(2-phenylethyl)phenyl. The diphosphenes and dithioxophosphoranes
Detection of the BICT State in a Borafluorene with High Stokes Shift Fluorescence
作者:Michael Pennington、Kyle C. Edwards、Fengrui Qu、David A. Dixon、Paul A. Rupar
DOI:10.1021/acs.organomet.4c00042
日期:2024.5.13
Four-coordinate aryl borafluorenes with boron–oxygen and boron–nitrogendativebonds can exhibit very large fluorescence Stokes shifts. The large Stokes shifts are hypothesized to arise from cleavage of the boron-donor dative bond in the excited state, via a mechanism called bond-cleavage-induced intramolecular charge transfer (BICT). The primary goal of this current investigation is to directly observe
具有硼-氧和硼-氮配位键的四配位芳基硼芴可以表现出非常大的荧光斯托克斯位移。据推测,大的斯托克斯位移是由激发态的硼供体配位键通过一种称为键断裂诱导的分子内电荷转移(BICT)的机制断裂而引起的。当前研究的主要目标是通过对四配位硼芴执行瞬态吸收光谱 (TAS) 来直接观察 BICT 状态,这提高了光学稳定性。合成了一种新型四配位芳基硼芴,其芳基环上具有配位B-O键和两个叔丁基部分。正如 BICT 假说所预测的那样,新型硼芴的 TAS 与激发态下单一三配位物质的存在相一致。 TAS 数据由荧光寿命测量和 DFT 计算支持。
Synthesis and Structure of the First Oxygen-Donor-Stabilized Organogermanium(II) Compounds
GeCl(2)(.)dioxane reacts with 1 and 2 equiv of [2,4-di-tert-butyl-6-(tert-butoxymethyl)lithium (t-BomxLi) to give the germanium(II) compounds t-BomxGeCl(1) and [t-Bomx](2)Ge (2), respectively. Reaction with 2 equiv of [2,4-di-tert-butyl-6-(iso-propoxymethyl)phenyl]lithium (i-PomxLi) affords [i-Pomx](2)Ge (3). Compounds 1-3 show intramolecular coordination of the alkoxy ligand to the germanium(II) center. The use of the 2,4-di-tert-butyl-6(methoxymethyl)phenyl ligand (Momx) does not lead to the expected base-stabilized germanium(II) species Momx(2)Ge but gives the germanium(IV) compound MomxGe[OCH2(2,4-di-tert-butylphenyl)] (Me) (4) as the result of an intramolecular O-CH3 bond oxidative addition process; X-ray crystal structure determinations are presented for 1, 2, and 4.