Synthesis, Structure, and Reactivity of Ga‐Substituted Distibenes and Sb‐Analogues of Bicyclo[1.1.0]butane

Abstract

CNMR spectroscopy,e lemental analysis,a nd single crystal X-ray diffraction. In addition, their bonding situation was analyzed by quantum chemical calculations.

From stable Sb- and Bi-centered radicals to a compound with a Ga=Sb double bond

“…1 and 4 show syn,syn configurations with the halogen atoms orienting toward the middle of the Ga-E-Ga skeleton. The Ga–Sb bond lengths in 1 [2.5899(4), 2.5909(3) Å] are comparable to those in [L(X)Ga] 2 Sb 4 [X = Cl 2.6008(13) Å, NMe 2 2.5975(5) Å] 33,36 , but shorter than in 2 [2.6265(11) Å], 3 [2.6979(2) Å], Ga-substituted distibenes [L(X)Ga] 2 Sb 2 [X = NMe 2 2.6477(3) Å, NMeEt 2.6433(6) Å, Cl 2.6461(2) Å] 33,36 , the sum of the covalent radii (Ga 1.24 Å; Sb 1.40 Å) 38 , as well as Lewis acid-base adducts R 3 Ga-SbR' 3 (2.84–3.02 Å) and heterocycles [R 2 GaSb(SiMe 3 ) 2 ] x ( x  = 2, 3; 2.65–2.76 Å) 39 . The Ga–Bi bond lengths in 4 [2.6640(9), 2.6663(9) Å] agree well with those of [L(OSO 2 CF 3 )Ga] 2 Bi 2 (2.655(1) Å] 40 , but are shorter than those in [L(OC 6 F 5 )Ga] 2 Bi 2 [2.693(6) Å] 40 , L(Et)GaBiEt 2 [2.6959(3) Å] 41 , LGa(BiEt 2 ) 2 [2.6961(6) Å, 2.7303(10) Å] 32 and the sum of the covalent radii (Ga 1.24 Å; Bi 1.51 Å) 38 .…”

“…2), traces of L(Cl)GaSb(H)Cp* 2 , LGaCl 2 and distibene [L(Cl)Ga] 2 Sb 2 36 , whereas the equimolar reaction yielded L(Cl)GaSb(Cl)Cp* 3 , which decomposed to LGaCl 2 , decamethylfulvalen (Cp* 2 ) and antimony metal (Supplementary Figs. 11, 12).…”

“…Continuing our investigations into Sb-X (X = Sb, C, N, Cl) bond activation reactions with monovalent Mg(I) and Ga(I) compounds 32–36 , here we report on the synthesis and characterization of stable neutral stibinyl and bismuthinyl radicals [L(X)Ga] 2 E· (E = Sb, X = Cl 1 , E = Bi, X = I 4 ) and the first compound containing a Ga=Sb double bond, LGaSbGa(Cl)L 5 .…”

A General Pathway for the Synthesis of Gallastibenes containing Ga=Sb Double Bonds

“…For instance, the Ga2−Sb1 bonds are significantly shorter than the Ga−Sb σ ‐bonds found in Lewis acid base adducts, [R 2 GaSbR′ 2 ] 3 heterocycles (2.663(2)–2.722(3) Å) and monomeric [(dmap)Et 2 GaSb(SiMe 3 ) 2 ] (2.648(1) Å; dmap=4‐dimethylaminopyridine) with threefold‐coordinated Sb atom . They are also shorter in comparison to Ga−Sb bonds observed in (LGa) 2 Sb 4 (2.6637(11)–2.6779(11) Å), [L(X)GaSb] 2 (X=NMe 2 2.6200(4) Å; NMeEt 2.6169(5) Å; Cl 2.58178(19) Å), [{L(X)Ga} 2 ( μ , η 1:1 ‐Sb 4 )] (X=NMe 2 2.5975(5) Å; Cl 2.6008(13) Å), and base‐stabilized [Cl( n ‐Pr 2 PhP)GaSbSi‐ i Pr 3 ] 2 (2.635(1)–2.655(1) Å) . The Ga−X bonds steadily increase in length (1.7923(9) Å 1 ; 2.2409(5) Å 2 ; 2.3917(3) Å 3 ; 2.6093(7) Å 4 ) due to the increasing atomic radii, as expected.…”

“…Our interest in the reaction mechanism leading to compounds containing Sb=Sb and Ga=Sb double bonds prompted us to re‐investigate the reaction of SbCl 3 with two equivalents of LGa at different reaction temperatures. At ambient temperature, this reaction almost entirely yields the known Ga‐substituted distibene [L(Cl)GaSb] 2 5 , whereas the cyclotristibine [L(Cl)GaSb] 3 6 is formed in moderate yield at 8 °C (Scheme ). 5 and 6 can be distinguished by NMR spectroscopy since the 1 H and 13 C NMR spectra of 5 clearly differ from those of 6 .…”