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Updated: Jun 5, 2026

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
Tetra-methyl biphenyl-2,3,3',4'-tetra-carboxyl-ate
Abstract:
The asymmetric unit of the title compound, C(20)H(18)O(8), contains two mol-ecules with small geometric differences. The dihedral angles between the benzene rings are 62.94 (12) and 59.99 (12)°. The dihedral angles between the carboxylate groups in the 2- and 3-positions are 81.72 (13) and 65.54 (15)°, respectively. However, the dihedral angles between the carboxylate groups in the 3' and 4'-positions are 67.24 (15) and 59.98 (17)°, respectively.
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