Synthesis, Structures, and Some Reactions of [(Thioacyl)thio]‐ and (Acylseleno)antimony and ‐bismuth Derivatives ((RCSS)xMR$\rm{_{{\bf 3 - }{\bf x}}^{\bf 1} }$ and (RCOSe)xMR$\rm{_{{\bf 3 - }{\bf x}}^{\bf 1} }$ with M = Sb, Bi and x = 1–3)

Abstract

AbstractA series of [(thioacyl)thio]‐ and (acylseleno)antimony and [(thioacyl)thio]‐ and (acylseleno)bismuth, i.e., (RCSS)xMR$\rm{_{3 - x}^1 }$ and (RCOSe)xMR$\rm{_{3 - x}^1 }$ (M = Sb, Bi, R1 = aryl, x = 1–3), were synthesized in moderate to good yields by treating piperidinium or sodium carbodithioates and ‐selenoates with antimony and bismuth halides. Crystal structures of (4‐MeC6H4CSS)2Sb(4‐MeC6H4) (9b′), (4‐MeOC6H4COSe)2Sb(4‐MeC6H4) (12c′), (4‐MeOC6H4COS)2Bi(4‐MeC6H4) (15c′), and (4‐MeOC6H4CSS)2BiPh (18c) along with (4‐MeC6H4COS)2SbPh (6b) and (4‐MeC6H4COS)3Sb (7b) were determined (Figs. 1 and 2). These compounds have a distorted square pyramidal structure, where the aryl or carbothioato (= acylthio) ligand at the central Sb‐ or Bi‐atom is perpendicular to the plane that includes the two carbodithioato (= (thioacyl)thio), carboselenato (= acylseleno), or carbothioato ligand and exist as an enantiomorph pair. Despite the large atomic radii, the CS ⋅⋅⋅ Sb distances in (RCSS)2MR1 (M = As, Sb, Bi; R1 = aryl) and the CO ⋅⋅⋅ Sb distances in (RCOS)xMR$\rm{_{3 - x}^1 }$ (M = As, Sb, Bi; x = 2, 3) are comparable to or shorter than those of the corresponding arsenic derivatives (Tables 2 and 3). A molecular‐orbital calculation performed on the model compounds (MeC(E)E1)3−xMMex (M = As, Sb, Bi; E = O, S; E1 = S, Se; x = 1, 2) at the RHF/LANL2DZ level supported this shortening of CE ⋅⋅⋅ Sb distances (Table 4). Natural‐bond‐orbital (NBO) analyses of the model compounds also revealed that two types of orbital interactions nS → σ$\rm{_{{{MC}}}^\ast }$ and nS → σ$\rm{_{{{MS(1)}}}^\ast }$ play a role in the (thioacyl)thio derivatives (MeCSS)3−xMMex (x = 1, 2) (Table 5). In the acylthio‐MeCOSMMe2 (M = As, Sb, Bi), nO → σ$\rm{_{{{MC}}}^\ast }$ contributes predominantly to the orbital interactions, but in MeCOSeSbMe2, none of nO → σ$\rm{_{{{MC}}}^\ast }$ and nO → σ$\rm{_{{{MSe}}}^\ast }$ contributes to the orbital interactions. The nS → σ$\rm{_{{{MC}}}^\ast }$ and nS → σ$\rm{_{{{MS(1)}}}^\ast }$ orbital interactions in the (thioacyl)thio derivatives are greater than those of nO → σ$\rm{_{{{MC}}}^\ast }$ and nO → σ$\rm{_{{{ME}}}^\ast }$ in the acylthio and acylseleno derivatives (MeCOE)3−xMMex (E = S, Se; M = As, Sb, Bi; x = 1, 2).▪The reactions of RCOSeSbPh2 (R = 4‐MeC6H4) with piperidine led to the formation of piperidinium diphenylselenoxoantimonate(1−) (= piperidinium diphenylstibinoselenoite) (H2NC5H10)+Ph2SbSe−, along with the corresponding N‐acylpiperidine (Table 6). Similar reactions of the bis‐derivatives (RCOSe)2SbR1 (R, R1 = 4‐MeC6H4) with piperidine gave the novel di(piperidinium) phenyldiselenoxoantimonate(2−) (= di(piperidinium) phenylstibonodiselenoite), [(H2NC5H10)+]2(PhSbSe2)2−, in which the negative charges are delocalized on the SbSe2 moiety (Table 6). Treatment of RCOSeSbR$\rm{_2^1 }$ (R, R1 = 4‐MeC6H4) with N‐halosuccinimides indicated the formation of Se‐(halocyclohexyl) arenecarboselenoates (Table 8). Pyrolysis of bis(acylseleno)arylbismuth at 150° gave Se‐aryl carboselenoates in moderate to good yields (Table 9).