5,6,7,8-Tetrafluoro-3lambda4delta2,1,2,4-benzothiaselenadiazine, 5,6,7,8-tetrafluoro-1,3lambda4delta2,2,4-benzodithiadiazine, and their hydrocarbon analogues: molecular and crystal structures.
5,6,7,8-Tetrafluoro-3lambda4delta2,1,2,4-benzothiaselenadiazine (1) is prepared by the intramolecular nucleophilic cyclization of C6F5SeN=S=NSiMe3 (2) mediated by CsF. According to an X-ray diffraction analysis, the heterocycle of 1 is bent along the Se(1)...N4 line by 6.0(2) degrees in the crystal. Despite the obvious similarities between 1 and its 1,3-dithia analogue (7) with respect to molecular composition and shape, the crystal packing of 1 is substantially different from that of 7. An interesting consequence of this is the inclusion of atmospheric N2 in the crystal lattice of the selenium derivative 1. The molecular structure and bonding of 1 have been investigated using quantum-chemical calculations at the DFT/B3LYP/6-311+G level of theory, and the results have been compared to those of 5,6,7,8-tetrafluoro-1,3lambda4delta2,2,4-benzodithiadiazine (7) and their hydrocarbon analogues (5 and 8).
Makarov
Alexander Yu
AY
Institute of Organic Chemistry, Russian Academy of Sciences, 630090 Novosibirsk, Russia.
Tersago
Karla
K
Nivesanond
Kanda
K
Blockhuys
Frank
F
Van Alsenoy
Christian
C
Kovalev
Mikhail K
MK
Bagryanskaya
Irina Yu
IY
Gatilov
Yuri V
YV
Shakirov
Makhmut M
MM
Zibarev
Andrey V
AV