Bulletin of the Chemical Society of Japan p. 2757 - 2763 (1997)
Update date:2022-08-17
Topics:
Yanagita, Mitsuhiro
Aoki, Izuo
Tokita, Sumio
The equilibrium between the colorless lactone (L) and the colored zwitterion (Z) forms of the fluoran compound 1, which has been widely used as a typical black color former in data-recording systems, has been studied by 13CNMR and electronic absorption spectroscopies. Fluoran 1 showed no visible absorption in aprotic solvents, while a black color appeared in phenolic solvents. The 13CNMR and signal of the spiro carbon of 1 in CDCl3 appeared at 84.2ppm, indicating that 1 exists substantially as L in aprotic solvents. In phenol d6 at 50°C, the signal of the spiro carbon in 1 shifted to a lower magnetic field and appeared in the sp2-hybridization region (δ = 162.7), suggesting that in phenol-d6 a cleavage of the C(spiro)-O bond in the lactone ring occurs and that the ring-opened Z form is produced. The equilibrium between L and Z depended strongly on the temperature and solvents. The high temperature and inhibition of the solute (1)-solvent interaction by steric hindrance, self-association and intramolecular chelation of the solvent shifted the L-Z equilibrium toward L. The thermodynamic parameters for the equilibrium reaction in phenolic solvents were also estimated.
View MoreZHEJIANG JIANYE CHEMICAL CO.,LTD.
Contact:86-571-64149273,64149234
Address:No. 48, Fuxi Road, Meicheng Town
Hebei Kangtai Pharmaceutical Co.,Ltd
Contact:+86-0317-3512963
Address:Wugang Road,Mengcun of Cangzhou City,Hebei Province ,China
Contact:
Address:
JiangXi Hong Run Chemical Co., Ltd
Contact:+86-0791-88521351
Address:XingHuo industrial zone in YongXiu county
Taizhou Chemedir Biopharm-tech Co., Ltd
Contact:+86 523 86200218
Address:G09, No. 1 Avenue China Medical City, Taizhou,Jiangsu, China
Doi:10.1002/adma.201705250
(2018)Doi:10.1002/(sici)1099-0690(199908)1999:8<1775::aid-ejoc1775>3.0.co;2-1
(1999)Doi:10.1248/cpb.25.171
(1977)Doi:10.1007/s11696-017-0183-y
(2017)Doi:10.1016/j.crci.2013.11.009
(2014)Doi:10.1016/S0277-5387(00)87097-7
(1983)