Synthesis and Characterization of the First Azastibatranes and Azabismatranes

Abstract

Syntheses of title compounds, viz. N(CH2CH2NR)3E (1, E = Sb, R = Me; 4, E = Bi, R = Me; 6, E = Sb, R = SiMe3; 8, E = Bi, R = SiMe3), by the reaction of E(NAlk2)3 (3, E = Sb, Alk = Et; 5, E = Bi, Alk = Me) with N(CH2CH2NMeH)3 (2) or N(CH2CH2NSiMe3H)3 (7) are reported. The reactions of SbCl3 with N[CH2CH2N(Me)Li]3 or N[CH2CH2N(SiMe3)Li]3 and BiCl3 with N[CH2CH2N(SiMe3)Li]3 resulted in compounds 1, 6, and 8, respectively. Composition and structures of all novel compounds were established by 1H and 13C NMR spectroscopy and mass spectrometry. The X-ray structural study of 8 clearly indicated the presence of transannular interaction BiNdat in this compound, while 6 possesses a long Sb...Ndat distance. The structural data obtained from geometry optimizations on 6 and 8 reproduce experimental trends, i.e., a decrease in the E-Ndat distance from Sb to Bi. The values of electron density in E-Ndat critical point and the Laplacian of charge density for 8 indicate that a closed-shell interaction exists between the metal atom and Ndat atom.

Intramolecular nucleophilic substitution in C6F5 moiety. The fluoride–dialkylamino exchange in decafluorodiphenlamino moiety

“…The Sb-N(C 6 F 5 ) 2 distance (2.111(1) Å ) and both Sb-NEt 2 distances (2.000(2), 2.110(1) Å ) are comparable with those previously found for triamido complexes without additional intramolecular coordination, e.g. in [17], Sb[N(p-Tol)SiMe 2 ] 3 SiCH 3 (2.050(2)-2.062(2) Å ) [18], and Sb[N(SiMe 3 )CH 2 CH 2 ) 3 ]N (2.049(2) Å ) [19], as well as for Sb(NMe 2 ) 3 according to the data of a electron diffraction study in the gas phase [20]. As expected Sb-N alkyl distances in 2 are shorter than those previously found for antimony tris-amides with higher coordination number due to strong additional intramolecular coordination such as in pyridilamide Sb{[2-(6-Me)C 5 H 3 N]N(SiMe 3 )} 3 (Sb-N cov = 2.163(4) Å ) [21].…”

“…Calc. (Found) for C 15 19 F NMR (C 6 D 6 , 188.28 MHz, ppm): À167.14 to À166.82 (m, 6F, p-F), À166.40 (br t, J = 25 Hz, 12F, m-F), À151.67 (br d, J = 20 Hz, 12F, o-F).…”

“…1 H, 13 C, and 19 F NMR spectra were recorded on a Bruker ARX 200 spectrometer at 23 8C. Chemical shifts in the 1 H and 13 C NMR spectra are given in ppm relative to internal Me 4 Si; in 19 F NMR experiments CFCl 3 was used as an external standard. Mass spectra (EI-MS) were recorded on a Finnigan MAT CH7A device using electron impact ionization at 70 eV, mass spectra (FD-MS) were recorded on a Finnigan MAT 95 S device; all assignments were made with reference to the most abundant isotopes.…”

ortho‐Directed Metathetical Fluoride/Amide Exchange in (Pentafluorophenyl)amides

“…The present theoretical method has been used, and has given very useful results, in antimony and bismuth chemistry. [22] Synthesis of (2-C 5 H 5 N)(C 6 F 5 )NH (1): n-Butyllithium (1.6  in hexane, 325 mL, 0.52 mol) was added dropwise to a stirred solution of 2-aminopyridine (48.94 g, 0.52 mol) in thf (50 mL) at -78°C. The reaction mixture was warmed to 25°C and stirred at room temperature for 4 h, and then all volatiles were removed under reduced pressure; thf (300 mL) was added to the residue, and then a solution of C 6 F 6 (48.36 g, 0.26 mol) in thf (60 mL) was added dropwise at -45°C over about 1 h. The reaction mixture was warmed to room temperature and refluxed for a further 24 h. Dilute hydrochloric acid was then carefully added to the reaction mixture to pH = 4.…”

“…Consequently, we believe that the theoretical method used gives reasonable results for indium derivatives; the appropriateness of this method for Sb and Bi compounds was confirmed by us previously. [1,22] Taking into consideration that no X-ray structure of prepared or proposed compounds is reported except for that of 9a, the calculated geometrical data for the molecules studied [series (a), with N Py ǞM] are of particular interest. The primary coordination environment of the Bi atom in 11a, 12a, and 20a-22a may be treated as a trigonal pyramid as the Bi-N Py distances are smaller than the sum of the van der Waals radii of bismuth and nitrogen (3.94 Å).…”