Ioan Ghesner

Syntheses and structures of (R2Bi)2E (E=S, Te) and cyclo-(RSbSe)2[W(CO)5]2 [R=CH(SiMe3)2]

Abstract (R2Bi)2E [E=S (1), Te (2); R=CH(SiMe3)2] are formed by reaction of R2BiCl with Na2S or Na2Te. The reaction of cyclo-(RSbSe)n [n=2, 3; R=CH(SiMe3)2] with W(CO)5THF (THF=tetrahydrofuran) in THF results in trapping of the dimer in cyclo-(RSbSe)2[W(CO)5]2 (3). The crystal structures of 1, 2, and 3 are reported.

n Ligands Coordination Compounds with Organoantimony and Sbn Ligands

Publisher Summary This chapter discusses the aspects of the coordination chemistry of organoantimony ligands and antimony ligands free of substituents without the inclusion of the other pnicogens. The ligand systems discussed include tertiary stibines, R 3 Sb and R 2 Sb, RSb or Sb units in different environments and with various coordination patterns. The majority of the complexes involve coordination on transition metals but complexes with main group (including Sb) acceptors are also discussed. General features of organoantimony ligands compared with their lighter congeners are related to the low stability of Sb–C or Sb–Sb bonds, to the relative weak Lewis basicity and to a larger tendency for higher coordination. Several comparative studies reveal a higher reactivity and flexibility of antimony ligand systems compared to analogous P or As compounds. However, the differences between related antimony and bismuth ligands appear to be considerably larger. Many tertiary stibines have donor properties similar to phosphines or arsines and they are easily coordinated witha large variety of metal complex fragments, whereas bismuthines are often weak donors. X-ray diffractometry is a very useful tool for the study of antimony ligands, including labile systems which are protected from rapid decomposition only in the sphere of complex.

Syntheses and crystal structures of a covalent trialkylantimony hydroxo bromide and related trialkylantimony(V) halides

R 3 SbBr 2 ( 1 ), RMe 2 SbBr 2 ( 2 ), or RMe 2 SbI 2 ( 3 ) [R=(Me 3 Si) 2 CH] are formed by addition of Br 2 or I 2 to R 3 Sb or RMe 2 Sb. (Me 3 SiCH 2 ) 3 Sb(Br)OH ( 4 ) is obtained by hydrolyzing 1 or (Me 3 SiCH 2 ) 3 SbBr 2 . The crystal structures of 1 , 3 , 4 and [(Me 3 SbBr) 2 ]O ( 5 ) [Me=CH 3 ] have been determined.

Syntheses and coordination chemistry of di-, tri-, and tetrastibanes, R2Sb(SbR′)nSbR2 (n=0, 1, 2)

Abstract Syntheses of the stibanes, t Bu 2 Sb(SbMe) n Sb t Bu 2 [ n =1 ( 1 ), 2 ( 2 )], ( t Bu 2 Sb) 2 ( 3 ), Mes 2 Sb(SbPh) n SbMes 2 [ n =1 ( 4 ), 2 ( 5 )] and of complexes with stibane ligands, [(CO) 5 Cr] 2 (Me 2 Sb) 2 ( 6 ), [Cr(CO) 4 (Me 2 Sb(SbR) 2 SbMe 2 )] ( 7 ), [Cr(CO) 4 (Ph 2 SbSbPhSbRSbPh 2 )] ( 8 ) (R=CH 2 SiMe 3 ) are reported. The crystal structures of 6 and 8 were determined by X-ray diffraction.

Phenylantimony(III) derivatives of tetraphenyldichalcogenoimidodiphosphinic acids. Crystal and molecular structure of PhSb[(XPPh2)(SPPh2)N]2 (X = O, S)

Abstract The reactions between PhSbCl 2 and M[(XPPh 2 )(YPPh 2 )N] (M=Na, K; X, Y=O, S), using 1:1 and 1:2 molar ratios, have been investigated. PhSbCl[(XPPh 2 )(YPPh 2 )N] and PhSb[(XPPh 2 )(YPPh 2 )N] 2 were isolated as microcrystalline powders and were characterized using IR and NMR ( 1 H, 31 P) spectroscopy. On standing in chloroform solution the chloro derivative PhSbCl[(SPPh 2 ) 2 N] was found to rearrange to PhSb[(SPPh 2 ) 2 N] 2 . The molecular structures of PhSb[(XPPh 2 )(SPPh 2 )N] 2 (X=O, S) were investigated by X-ray diffraction. The crystals of both compounds contain monomeric units with asymmetric chelating ligand fragments, resulting in a square pyramidal CSbX 2 S 2 core with an apical phenyl group. The antimony lone pair of electrons appears to be stereochemically active and is located trans to the phenyl group, as suggested by the displacement of the metal atom from the best basal plane formed by the chalcogens in the opposite direction with respect to the apical carbon. For the monothio derivative, the molecule displays different ligand behaviour, i.e. O - and S -primary coordinations, respectively.

Lithium tetraorganodichalcogenoimidodiphosphinates. Crystal structure of [Li{(OPPh2)(SPMe2)N}·2H2O]2, a dimer formed through oxygen-bridging phosphorus ligands

Abstract Lithium tetraorganodichalcogenoimidodiphosphinates, Li[(XPR2)(YPR′2)N], were prepared and investigated by means of IR and multinuclear (1H, 13C, 31P) NMR spectroscopy. The crystal and molecular structure of lithium P,P-dimethyl-P′,P′-diphenyl-P-thioimidodiphosphinate was determined by X-ray diffraction. The asymmetric unit contains two independent dimeric associations, [Li{(OPPh2)(SPMe2)N}·2H2O]2, built up through O–phosphorus ligand bridges and separated by normal van der Waals distances. This results in the formation of a perfectly planar Li2O2 four-membered cycle with tetrahedral coordination around each metal atom completed by two additional O-water atoms. The sulfur atoms of the monothioimidodiphosphinato groups, which are not involved in coordination to a metal center, are on opposite sides of the Li2O2 cycle.

Syntheses of isobutylantimony compounds, cyclo-RnSbn (n = 4, 5), R4Sb2, and crystal structure of R3SbBr2; R = Me2CHCH2

Abstract Dehalogenation reactions of RSbBr2 or R2SbBr (R=Me2CHCH2) with Mg in tetrahydrofuran give cyclo-RnSbn (1, n=4, 5) or R4Sb2 (2). R3SbBr2 (3) is formed by addition of Br2 to R3Sb. The crystals of 3 consist of trigonal bipyramidal molecules with apical bromine atoms.