DFT calculations, structural and spectroscopic studies on the products formed between IBr and N,N'-dimethylbenzoimidazole-2(3H)-thione and -2(3H)-selone.
The NBO charge distribution calculated at DFT level on the [LEX](+) species [LE=N,N'-dimethylbenzoimidazole-2(3H)-thione (3) and -2(3H)-selone (4)(Scheme 1); X=I, Br] suggests that the most likely products from the reaction 3 of 4 and with IBr are the 10-X-2 charge-transfer (CT) adduct and the 10-Se-3 "T-shaped" hypervalent adduct featuring a linear Br--Se--I system, respectively. This prediction is confirmed by the synthesis, and X-ray diffraction analysis of 3.IBr (I) and 4.I(0.72)Br(1.28)(II). In particular II, is a 10-Se-3 "T-shaped" hypervalent adduct containing an almost linear X--Se--X system [X--Se--X 179.07(3) degrees, X=I(0.36)/Br(0.64)], which is roughly perpendicular to the average plane of the benzoimidazole moiety. The FT-Raman spectra of I and II agree very well with their structural features. In particular, the complexity of the FT-Raman spectrum of II reflects the disorder in the X-ray crystal structure of this compound.
Aragoni
M Carla
MC
Dipartimento di Chimica Inorganica ed Analitica, Università di Cagliari, S.S. 554 Bivio per Sestu, 09042 Monserrato (CA), Italy.
Arca
Massimiliano
M
Demartin
Francesco
F
Devillanova
Francesco A
FA
Garau
Alessandra
A
Isaia
Francesco
F
Lippolis
Vito
V
Verani
Gaetano
G
D000465:Algorithms; D001562:Benzimidazoles / Q000737:chemistry*; D052160:Benzothiazoles / Q000737:chemistry*; D035843:Biomedical Research; D001965:Bromides / Q000737:chemistry*; D007454:Iodides / Q000737:chemistry*; D008958:Models, Molecular; D018036:Selenium Compounds / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013871:Thiones / Q000737:chemistry*; D014961:X-Ray Diffraction
D001562:Benzimidazoles; D052160:Benzothiazoles; D001965:Bromides; D007454:Iodides; C517165:N,N'-dimethylbenzoimidazole-2(3H)-selone; C517166:N,N'-dimethylbenzoimidazole-2(3H)-thione; D018036:Selenium Compounds; D013871:Thiones; C054509:iodobromine