41969-71-5Relevant articles and documents
Stereoselectivity in the double reductive alkylation of pyrroles: Synthesis of cis-3,4-disubstituted pyrrolidines
Donohoe, Timothy J.,Harji, Rakesh R.,Cousins, Rick P. C.
, p. 141 - 142 (1999)
The preparation and Birch reduction of a 1,3,4-tri-substituted pyrrole is described: the heterocycle is loaded with electron-withdrawing groups and undergoes a double reductive alkylation reaction to yield cis-3,4-disubstituted pyrrolidines.
Synthesis and photophysical studies of a chlorin sterically designed to prevent self-aggregation
De Assis, Francisco F.,De Souza, Juliana M.,Assis, Beatriz H.K.,Brocksom, Timothy J.,De Oliveira, Kleber T.
, p. 153 - 159 (2013)
Synthesis and photophysical evaluations of a new non-aggregating chlorin derivative are described. A b-octa(carboxyethyl)porphyrin 3 was synthesized in 2 steps starting from pyrrole-3,4-dicarboxylic acid diethyl ester (2). The new chlorin derivative 6 was obtained through a 1,3-dipolar cycloaddition using benzyl azomethine ylide. Chlorin 6 presents a molecular scaffold in an "L" shape avoiding aggregation in solutions at 1-27 mM. Photophysical properties were measured, and indicate that this new compound can be considered a useful candidate for PDT studies.
The role of porphyrin peripheral substituents in determining the reactivities of ferrous nitrosyl species
Amanullah, Sk,Dey, Abhishek
, p. 5909 - 5921 (2020/07/13)
Ferrous nitrosyl {FeNO}7 species is an intermediate common to the catalytic cycles of Cd1NiR and CcNiR, two heme-based nitrite reductases (NiR), and its reactivity varies dramatically in these enzymes. The former reduces NO2- to NO in the denitrification pathway while the latter reduces NO2- to NH4+ in a dissimilatory nitrite reduction. With very similar electron transfer partners and heme based active sites, the origin of this difference in reactivity has remained unexplained. Differences in the structure of the heme d1 (Cd1NiR), which bears electron-withdrawing groups and has saturated pyrroles, relative to heme c (CcNiR) are often invoked to explain these reactivities. A series of iron porphyrinoids, designed to model the electron-withdrawing peripheral substitution as well as the saturation present in heme d1 in Cd1NiR, and their NO adducts were synthesized and their properties were investigated. The data clearly show that the presence of electron-withdrawing groups (EWGs) and saturated pyrroles together in a synthetic porphyrinoid (FeDEsC) weakens the Fe-NO bond in {FeNO}7 adducts along with decreasing the bond dissociation free energies (BDFENH) of the {FeHNO}8 species. The EWG raises the E° of the {FeNO}7/8 process, making the electron transfer (ET) facile, but decreases the pKa of {FeNO}8 species, making protonation (PT) difficult, while saturation has the opposite effect. The weakening of the Fe-NO bonding biases the {FeNO}7 species of FeDEsC for NO dissociation, as in Cd1NiR, which is otherwise set-up for a proton-coupled electron transfer (PCET) to form an {FeHNO}8 species eventually leading to its further reduction to NH4+.
Evaluating the influence of heteroatoms on the electronic properties of aryl[3,4-c]pyrroledione based copolymers
Hale, Benjamin J.,Elshobaki, Moneim,Gebhardt, Ryan,Wheeler, David,Stoffer, Jon,Tomlinson, Aimée,Chaudhary, Sumit,Jeffries-EL, Malika
, p. 85 - 92 (2016/12/26)
A donor-acceptor-type conjugated copolymer (PBDT-PPD) composed of benzodithiophene (BDT) and pyrrolopyrroledione (PPD) was synthesized using the Stille cross-coupling reaction. Using both experimental and theoretical data, the optical, electrochemical, and photovoltaic properties of PBDT-PPD were compared with those of its sulfur analog, PBDT-TPD, which is composed of BDT and thienopyrroledione (TPD). The optical bandgaps of the polymers were determined to be 1.86 and 2.20 eV, respectively. While both materials possessed similar highest occupied molecular orbital (HOMO) levels, the lowest unoccupied molecular orbital (LUMO) level for PBDT-PPD was raised relative to that of PBDT-TPD. Devices incorporating PBDT-PPD had a higher open-circuit voltage and fill factor, yet drastically lower short-circuit current density (Jsc) than PBDT-TPD leading to a lower power conversion efficiency (PCE). The lack of significant intramolecular charge transfer (ICT) combined with the high LUMO of PBDT-PPD resulted in poor spectral overlap with the solar spectrum, lowering Jsc. Additionally, there was poor electron injection into PCBM, which also reduced the PCE.
