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The in situ reduction of the N,C,N-chelated bismuth(III) chloride (ArBiCl2) (where Ar = 2,6-(Me2NCH2)2C6H3) with 2 equivalents of K[B(s-Bu)3H] produced an unstable bismuth(I) compound ArBi (1) that was trapped by its coordination toward suitable transition metal fragments. Using this strategy a set of complexes with Group 6 metal carbonyls was obtained, i.e. [ArBiM(CO)5] (1-M; where M = Cr, Mo, W). The treatment of 1 with [Fe2(CO)9] provided the expected complex [ArBiFe(CO)4] (1-Fe) along with [ArBi(Fe(CO)4)2] (1-Fe2) as a minor by-product. By contrast, the reaction of 1 with the dinuclear complex [Co2(CO)8] furnished ionic complex [(ArBi)2Co(CO)3][Co(CO)4] (1-Co). All compounds were characterized using 1H and 13C{1H} NMR, IR and Raman spectroscopy. Molecular structures of 1-Cr, 1-Fe, 1-Fe2 and 1-Co were determined by the help of single-crystal X-ray diffraction analysis.

The reduction of N,C,N-chelated antimony(III) chlorides [C 6H 3-2,6-(CH=NR) 2]SbCl 2(R=Ph (1), tBu (2), Dip (3); Dip=2,6-iPr 2C 6H 3) with an appropriate amount of KC 8or Li[AlH 4] resulted in the formation of rare examples of monomeric stibinidenes [C 6H 3-2,6-(CH=NR) 2]Sb (R=Ph (4), tBu (5), Dip (6)). Similarly, the reduction of compounds 1 or 2 by two equivalents of K[B(sBu) 3H] led to the stibinidenes 4 and 5. In contrast, the analogous reaction of compound 3 resulted in the formation of an unprecedented stibinidene [C 6H 3-2-(CH=NR)-6-(CH 2NHR)]Sb (7) (R=Dip), in which the hydrogen atoms that come from the K[B(sBu) 3H] are incorporated into the ligand backbone. To gain further insight into this intriguing reactivity with K[B(sBu) 3H] and to assess the influence of the substitution at both the antimony atom and pendant substituents, we prepared compounds [C 6H 3-2-(CH=NDip)]Sb(Ph)Cl (8) and [C 6H 2-2-(CH=NDip)-4,6-(tBu) 2]SbCl 2(9). The treatment of compound 8 with K[B(sBu) 3H] smoothly led to the 1-Ph-2-Dip-1H-2,1-benzazastibole (11), whereas the reaction of compound 9 with K[B(sBu) 3H] resulted in either tBu-substituted 1-Cl-2-Dip-1H-2,1-benzazastibole (13) or the formation of unprecedented Sb−Sb dimer bis(2-Dip-1H-2,1-benzazastibole) (12) depending on the reaction stoichiometry. The miscellaneous reactivity of antimony(III) precursors with reducing agents together with the structure and bonding of the resulting products has also been investigated from a theoretical point of view.

N,C,N-Chelated pnictinidenes ArE [where E = As (1), Sb (2) or Bi (3); Ar = C 6H 3-2,6-(CH=Nt-Bu) 2] were used as ligands for the coordination of transition metal carbonyls. Thus, the reaction of 1-3 with [M(CO) 5THF] (where M = Cr, W) or [Mo(CO) 5(Me 3N)] gave complexes [(ArE)M(CO) 5] [where E = As and M = Cr (1a), Mo (1b), W (1c); E = Sb and M = Cr (2a), Mo (2b), W (2c); E = Bi and M = Cr (3a), Mo (3b), W (3c)]. Analogously, the treatment of 1-3 with [Fe 2(CO) 9] resulted in the formation of the complexes [(ArE)Fe(CO) 4] [where E = As (1d), Sb (2d) or Bi (3d)]. All compounds were characterized by 1H and 13C NMR spectroscopy, Raman, IR and UV-Vis spectroscopy. The molecular structures of the majority of the compounds (except 1b and 1c) were also determined by the single-crystal X-ray diffraction analysis. Furthermore, the structure and bondingof the title compounds have also been thoroughly investigated using a computational approach.

The treatment of N,C,N-chelated antimony(III) and bismuth(III) chlorides [C6H3-2,6-(CH=NR)2]MCl2 [R = tBu and M = Sb (1) or Bi (2); R = Dmp and M = Sb (3) or Bi (4)] (Dmp = 2,6-Me2C6H3) with one molar equivalent of Ag[CB11H12] led to a smooth formation of corresponding ionic pairs {[C6H3-2,6-(CH=NR)2]MCl}+[CB11H12]– [R = tBu and M = Sb (7) or Bi (8), R = Dmp and M = Sb (9) or Bi (10)]. Similarly, the reaction of C,N-chelated analogues [C6H2-2-(CH=NDip)-4,6-(tBu)2]MCl2 [M = Sb (5) or Bi (6), Dip = 2′,6′-iPr2C6H3] gave compounds {[C6H2-2-(CH=NDip)-4,6-(tBu)2]MCl}+[CB11H12]– [M = Sb (11) or Bi (12)]. All compounds 7–12 were characterized with 1H, 11B and 13C{1H} NMR spectroscopy, ESI-mass spectrometry, IR spectroscopy, and molecular structures of 7–9 and 12 were determined by the help of single-crystal X-ray diffraction analysis. In contrast, all attempts to cleave also the second M–Cl bond in 7–12 using another molar equivalent Ag[CB11H12] remained unsuccessful. Nevertheless, the reaction between 7 (or 8) and Ag[CB11H12] produced unprecedented adducts of both reagents namely {[C6H3-2,6-(CH=NtBu)2]SbCl}22+[Ag2(CB11H12)4]2– (13) and {[C6H3-2,6-(CH=NtBu)2]BiCl}+[Ag(CB11H12)2]– (14) in a reproducible manner. The molecular structures of these sparingly soluble compounds were determined by single-crystal X-ray diffraction analysis.

N,C,N-chelated antimony(III) and bismuth(III) chlorides L1,2MCl2 (1–4: for L1, M = Sb (1), Bi (3); for L2, M = Sb (2), Bi (4)) containing ligands L1,2 (where L1 = C6H3-2,6-(CH═N-t-Bu)2, L2 = C6H3-2,6-(CH═N-2′,6′-Me2C6H3)2) were prepared by reactions of lithium precursors with SbCl3 or BiCl3. The identities of 1–4 were established both in solution (1H and 13C NMR spectroscopy) and, in the case of 1–3, in the solid state using single-crystal X-ray diffraction analysis. Treatment of antimony derivatives 1 and 2 with 2 molar equiv of R′Li (R = Me, n-Bu, Ph) yielded the set of substituted 1,3-(R′)2-2-R-7-(CH═NR)-1H-2,1-benzazastiboles 5–10 (where R = t-Bu, 2,6-Me2C6H3 and R′ = Me, n-Bu, Ph) as a result of a nucleophilic attack of one of the lithium compounds across the imino C═N functionality. In contrast, analogous reactions between bismuth congeners 2 and 4 and R′Li (2 equiv, R′ = Me, Ph) gave L1,2BiR′2 (11–13: for L1, R′ = Me (11), Ph (12); for L2, R′ = Me (13)) as products of substitution of chlorine atoms...

N,N- and N,N,N-chelated antimony(III) and bismuth(III) chlorides L(1-3)MCl2 1-4 [for L(1): M = Sb (1), for L(2): M = Sb (2) and for L(3): M = Sb (3) and Bi (4)], containing ligands L(1-3) derived from the pyrrole ring (where L(1) = C4H3N-2-(CH[double bond, length as m-dash]N-2',6'-iPr2C6H3), L(2) = C4H2N-2,5-(CH2NMe2)2, L(3) = C4H2N-2,5-(CH2NC4H8)2), were prepared by the treatment of lithium precursors with SbCl3 or BiCl3. Molecular structures 1-4 of were described both in solution (NMR spectroscopy) and in the solid state (single-crystal X-ray diffraction analysis). Structures of 1-4 were also subjected to a density functional theory study.

N,C,N-Chelated pnictinidenes ArE [where E = As (1), Sb (2) or Bi (3); Ar = C

The reaction of stibinidene and bismuthinidene ArM [where Ar=C6 H3 -2,6-(CH=NtBu)2 ; M=Sb (1), Bi (2)] with transition metal (TM) carbonyls Co2 (CO)8 and Mn2 (CO)10 produced unprecedented ionic complexes [(ArM)2 Co(CO)3 ](+) [Co(CO)4 ](-) and [(ArM)2 Mn(CO)4 ](+) [Mn(CO)5 ](-) [where M=Sb (3, 5), Bi (4, 6)]. The pnictinidenes 1 and 2 behaved as two-electron donors in this set of compounds. Besides the M→TM bonds, the topological analysis also revealed a number of secondary interactions contributing to the stabilization of cationic parts of titled complexes.

The reduction of N,C,N-chelated bismuth chlorides [C6H3-2,6-(CH[DOUBLE BOND]NR)2]BiCl2 [where R=tBu (1), 2′,6′-Me2C6H3 (2), or 4′-Me2NC6H4 (3)] or N,C-chelated analogues [C6H2-2-(CH[DOUBLE BOND]N-2′,6′-iPr2C6H3)-4,6-(tBu)2]BiCl2 (4) and [C6H2-2-(CH2NEt2)-4,6-(tBu)2]BiCl2 (5) is reported. Reduction of compounds 1–3 gave monomeric N,C,N-chelated bismuthinidenes [C6H3-2,6-(CH[DOUBLE BOND]NR)2]Bi [where R=tBu (6), 2′,6′-Me2C6H3 (7) or 4′-Me2NC6H4 (8)]. Similarly, the reduction of 4 led to the isolation of the compound [C6H2-2-(CH[DOUBLE BOND]N-2′,6′-iPr2C6H3)-4,6-(tBu)2]Bi (9) as an unprecedented two-coordinated bismuthinidene that has been structurally characterized. In contrast, the dibismuthene {[C6H2-2-(CH2NEt2)-4,6-(tBu)2]Bi}2 (10) was obtained by the reduction of 5. Compounds 6–10 were characterized by using 1H and 13C NMR spectroscopy and their structures, except for 7, were determined with the help of single-crystal X-ray diffraction analysis. It is clear that the structure of the reduced products (bismuthinidene versus dibismuthene) is ligand-dependent and particularly influenced by the strength of the N→Bi intramolecular interaction(s). Therefore, a theoretical survey describing the bonding situation in the studied compounds and related bismuth(I) systems is included. Importantly, we found that the C3NBi chelating ring in the two-coordinated bismuthinidene 9 exhibits significant aromatic character by delocalization of the bismuth lone pair.