Phthalocrowns: Isoindoline–Crown Ether Macrocycles

The reaction of diiminoisoindoline with amine-terminated polyethers results in the formation of phthalocrown macrocycles. For <i>n</i> = 1 (where <i>n</i> is the number of ether units), a 2 + 2 condensation takes place, but for <i>n</i> = 2 and 3, a 1 + 1 macrocycle formation occurs. The <i>n</i> = 2 phthalocrown is particularly stable due to a strong intramolecular hydrogen bond, but the <i>n</i> = 3 ring hydrolyzes to form a 3-imino-1-oxoisoindoline derivatized crown ether species. For the <i>n</i> = 1 phthalocrown, we observed dynamic behavior in the ¹H NMR spectrum, and using VTNMR were able to measure a Δ<i>G</i>^⧧ = 44.6 kJ/mol for proton exchange

Phthalocrowns: Isoindoline–Crown Ether Macrocycles

The reaction of diiminoisoindoline with amine-terminated polyethers results in the formation of phthalocrown macrocycles. For <i>n</i> = 1 (where <i>n</i> is the number of ether units), a 2 + 2 condensation takes place, but for <i>n</i> = 2 and 3, a 1 + 1 macrocycle formation occurs. The <i>n</i> = 2 phthalocrown is particularly stable due to a strong intramolecular hydrogen bond, but the <i>n</i> = 3 ring hydrolyzes to form a 3-imino-1-oxoisoindoline derivatized crown ether species. For the <i>n</i> = 1 phthalocrown, we observed dynamic behavior in the ¹H NMR spectrum, and using VTNMR were able to measure a Δ<i>G</i>^⧧ = 44.6 kJ/mol for proton exchange

Phthalocrowns: Isoindoline–Crown Ether Macrocycles

The reaction of diiminoisoindoline with amine-terminated polyethers results in the formation of phthalocrown macrocycles. For <i>n</i> = 1 (where <i>n</i> is the number of ether units), a 2 + 2 condensation takes place, but for <i>n</i> = 2 and 3, a 1 + 1 macrocycle formation occurs. The <i>n</i> = 2 phthalocrown is particularly stable due to a strong intramolecular hydrogen bond, but the <i>n</i> = 3 ring hydrolyzes to form a 3-imino-1-oxoisoindoline derivatized crown ether species. For the <i>n</i> = 1 phthalocrown, we observed dynamic behavior in the ¹H NMR spectrum, and using VTNMR were able to measure a Δ<i>G</i>^⧧ = 44.6 kJ/mol for proton exchange

Phthalocrowns: Isoindoline–Crown Ether Macrocycles

The reaction of diiminoisoindoline with amine-terminated polyethers results in the formation of phthalocrown macrocycles. For <i>n</i> = 1 (where <i>n</i> is the number of ether units), a 2 + 2 condensation takes place, but for <i>n</i> = 2 and 3, a 1 + 1 macrocycle formation occurs. The <i>n</i> = 2 phthalocrown is particularly stable due to a strong intramolecular hydrogen bond, but the <i>n</i> = 3 ring hydrolyzes to form a 3-imino-1-oxoisoindoline derivatized crown ether species. For the <i>n</i> = 1 phthalocrown, we observed dynamic behavior in the ¹H NMR spectrum, and using VTNMR were able to measure a Δ<i>G</i>^⧧ = 44.6 kJ/mol for proton exchange

A New Highly Fluorescent and Symmetric Pyrrole–BF₂ Chromophore: BOPHY

The new fluorescent chromophore BOPHY can be readily synthesized in two steps from commercially available reagents via the coupling of pyrrole-2-carboxaldehyde with hydrazine followed by reaction with BF₃. The resultant symmetric and dimeric tetracycle is composed of two BF₂ units in six-membered chelate rings appended with pyrrole units on the periphery. The quantum yields of fluorescence for the unmodified compound and the tetramethyl variant are near unity, with values of 95 and 92%, respectively, in CH₂Cl₂. We have probed the electronic structure of this compound via cyclic voltammetry and density functional theory analysis