US EPA

6866069 

Journal Article 

Effect of Cp-Ligand Methylation on Rhodium(III)-Catalyzed Annulations of Aromatic Carboxylic Acids with Alkynes: Synthesis of Isocoumarins and PAHs for Organic Light-Emitting Devices 

Molotkov, AP; Arsenov, MA; Kapustin, DA; Muratov, DV; Shepel', NE; Fedorov, YV; Smol'yakov, AF; Knyazeva, EI; Lypenko, DA; Dmitriev, AV; Aleksandrov, AE; Maltsev, EI; Loginov, DA 

2020 

1 

ChemPlusChem
EISSN: 2192-6506 

WILEY-V C H VERLAG GMBH 

WEINHEIM 

85 

2 

334-345 

English 

32048812 

10.1002/cplu.202000048 

WOS:000516845200010 

https://onlinelibrary.wiley.com/doi/abs/10.1002/cplu.202000048
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An efficient protocol was developed for the synthesis of π-extended isocoumarins and polycyclic aromatic hydrocarbons based on the oxidative coupling of aromatic carboxylic acids with internal alkynes catalyzed by (cyclopentadienyl)rhodium complexes. The coupling chemoselectivity strongly depends on whether Cp or the methylated Cp* ligands are used. The pentamethyl derivative [Cp*RhCl2 ]2 predominantly gives isocoumarins, while the non-methylated complex [CpRhI2 ]n produces naphthalene derivatives. The polyaromatic carboxylic acids (such as 1-naphthoic acid, 1-pyrenecarboxylic acid, fluorene-1-carboxylic acid, and dibenzofuran-4-carboxylic acid) are suitable for this approach. A mixture of Cp*H/RhCl3 can be used as a catalyst instead of [Cp*RhCl2 ]2 . The structures of 3,4-diphenylindeno[1,2-h]isochromen-1(11H)-one and 7,10-dimethyl-8,9-diphenylbenzo[pqr]tetraphene were determined by X-ray diffraction. In addition, the optical properties of the prepared compounds were studied. 7,8-Diphenyl-10H-phenaleno[1,9-gh]isochromen-10-one was employed as an emissive layer for OLED manufacturing. The OLED emits yellow-green light with a maximum intensity 1740 cd ⋅ m-2 at 15 V.