Energetic effects of ether and ketone functional groups in 9,10-dihydroanthracene compound

Thermodynamic study of 9-anthracenecarboxylic acid

“…A similar effect is found for xanthene, as shown in figure 2D. The enthalpic increment due to the entrance of a carboxylic group in its 9th position, calculated from the values of D f H m ðgÞ of xanthene, (41.8 ± 3.5) kJ Á mol À1 [35] and 9-xanthenecarboxylic acid, À(315.8 ± 3.3) kJ Á mol À1 [36], À(357.6 ± 4.8) kJ Á mol À1 , almost matches the one found for anthracene. This result shows that the 9-xanthenecarboxylic acid cannot also assume a planar geometry due to steric repulsions with the peri hydrogens at the 9-position and, consequently, the conjugation interaction is lost.…”

Experimental and computational thermochemical studies of 9-R-xanthene derivatives (ROH, COOH, CONH2)

“…The xanthene structure is symmetrical and has a slight deviation from planarity [12]. With the introduction of the hydroxyl, carboxyl and carboxamide groups in the position 9 of the xanthene substructure, it is possible to verify some changes between the structures of the xanthene derivatives considered in this work.…”

“…The objectives of this work are the understanding of the energetic effect of three different substituents on position 9 of xanthene (figure 1) and, anchored on data coming from some other studies performed earlier, the quantification of the effects of substituting an oxygen heteroatom by sulfur in heteropolycyclic compounds [7][8][9][10][11][12][13].…”

Influence of Hydroxyl Functional Group on the Structure and Stability of Xanthone: A Computational Approach

“…A literature survey showed the scarcity of thermodynamic data for heteropolycyclic compounds that motivated our involvement in a systematic study of compounds structurally formed by two benzene rings fused to a pentagonal or hexagonal central ring, containing oxygen, sulfur or nitrogen as heteroatoms [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. This work has been developed in a “duo dynamic” between the experimental and computational studies of those species, with the main goal of determining their thermodynamic properties, among others.…”