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Organobismuth(III) compounds containing (N,C,N)-pincer ligands were prepared and characterized both in solution and in the solid state. Compound RBiCl2 1 [R = 2,6-(Me2NCH2)2C6H3] was obtained from RLi and BiCl3 (1:1 molar ratio). RBiBr2 2 and RBiI2 3 were obtained by halogen-exchange reactions from 1. Reaction of 1 with MeMgI afforded RBi(Me)I 4. Compound R2BiCl 5, obtained from RLi and BiCl3, is rearranged in solution to 1 and R3Bi. The molecular structures of compounds 1−5 were established by single-crystal X-ray diffraction. All dihalides RBiX2 show a T-shaped CBiX2 core. They are the first stable compounds corresponding to the edge inversion “transition state” at the bismuth center, stabilized by two strong intramolecular N→Bi interactions in trans positions to each other, which contribute to an overall distorted square pyramidal (N,C,N)BiX2 coordination geometry. The electronic structure of [2,6-(Me2NCH2)2C6H3]BiCl2 (1) was analyzed by density functional theory (DFT) calculations, which provide evidence that the stabilization of the square pyramidal geometry of bismuth is electronic rather than steric in nature.

R2BiOH (1) [R = 2-(Me2NCH2)C6H4] and (R2Bi)2O (2) are formed by hydrolysis of R2BiCl with KOH. Single crystals of were obtained by air oxidation of (R2Bi)2. The reaction of R2BiCl and Na2CO3 leads to (R2Bi)2CO3 (3). 3 is also formed by the absorption of CO2 from the air in solutions of 1 or 2 in diethyl ether or toluene. (R2Bi)2S (4) is obtained from R2BiCl and Na2S or from (R2Bi)2 and S8. Exchange reactions between R2BiCl and KBr or NaI give R2BiX [X = Br (5), I (6)]. The reaction of RBiCl2 (7) with Na2S and [W(CO)5(THF)] gives cyclo-(RBiS)2[W(CO)5]2 (8). cyclo-(R'BiS)2 (9) [R' = 2,6-(Me2NCH2)2C6H3] is formed by reaction of R'BiCl2 and Na2S. The structures of were determined by single-crystal X-ray diffraction.

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The reaction of RLi [R = 2,6-{MeN(CH2CH2)2NCH2}2C6H3 ] with BiCl3 (1:1 molar ratio) afforded RBiCl2 (2). RBiBr2 (3) and RBiI2 (4) were obtained by halogen-exchange reactions from 2 . The organobismuth(III) dihalides containing the new steric demanding (N,C,N)-pincer ligand were characterized both in solution and solid state. The molecular structures of compounds were established by single-crystal X-ray diffraction. They all show a T-shaped CBiX(2) core, stabilized by two strong intramolecular N-->Bi interactions in trans positions to each other. The overall (N,C,N)BiX2 core exhibits a distorted square-pyramidal coordination geometry. The NMR studies provided evidences for the presence of internal nitrogen-bismuth coordination in solution too. DFT calculations were performed on the related species [2,6-(R(2)NCH(2))(2)C(6)H(3)]BiX(2) (R = H, Me; X = Cl, Br, I) in order to elucidate the bond nature and vibrational spectroscopic features of these compounds.

R 2 SbH (1) and R 2 BiH (2) [R ) (Me 3 Si) 2 CH] are formed by reactions of the corresponding chlorides with LiAlH 4 . 1 is stable up to 100 °C. Decomposition of 2 at room temperature leads to R 2 Bi-BiR 2 (3) and H 2 . The crystal structure of 3 consists of molecules in a near trans conformation. 1 H NMR studies of 3 in C 6 D 6 show that the diastereotopic Me 3 Si groups become equivalent with increasing concentration and temperature. Stibine, bismuthine, EH 3 (E ) Sb, Bi), and many organic derivatives, REH 2 and R 2 EH, decompose at or below room temperature with formation of H 2 , E, R 3 E, or compounds with E-E bonds. 1 Usually hydrides of bismuth are less stable than the corresponding antimony derivatives. Stable organostibines (RSbH 2 , R ) 2,6-(2,4,6

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