Simón Hernández

Trans Influence of Triphenylstibine: Crystal Structures of cis‐[PtBr2(SbPh3)2], trans‐[PtBr(Ph)(SbPh3)2], [NMe4][PtBr3(SbPh3)], and cis‐[PtBr2(SbPh3)(PPh3)]

The work reports the unexpected reaction of diphenyldibromo antimonates (III) with PtCl2 and cis-[PtCl2(PPh3)2]. The reaction gives triphenylstibine containing PtII complexes viz. cis-[PtBr2(SbPh3)2] (1), trans-[[PtBr(Ph)(SbPh3)2] (2), [NMe4][PtBr3(SbPh3)] (3), and cis-[PtBr2(PPh3)(SbPh3)] (4). All the complexes were characterised by elemental analyses, IR, Raman, 195Pt NMR, FAB mass spectroscopy and X-ray crystallography. A plausible mechanism via the phenyl migration is proposed for the formation of these complexes. The average Pt–Br distance in 1 is 2.456(2) A, in 2 2.496 A(trans to Ph) while in 3 it is 2.476 A (trans to Sb) implying a comparable trans influence of Ph3Sb and Ph3P. Transeinflus von Triphenylantimon: Die Kristallstrukturen von cis-[PtBr2(SbPh3)2], trans-[PtBr(Ph)(SbPh3)2], [NMe4][PtBr3(SbPh3)] und cis-[PtBr2(SbPh3)(PPh3)] Es wird uber die unerwartete Reaktion von [Ph2SbBr2]– mit PtCl2 und cis-[PtCl2(PPh3)2] berichtet, die die Platin(II)-Komplexe cis-[PtBr2(SbPh3)2] (1), trans-[[PtBr(Ph)(SbPh3)2] (2), [NMe4][PtBr3(SbPh3)] (3) und cis-[PtBr2(PPh3)(SbPh3)] (4) ergibt. Die Komplexe werden durch Elementaranalyse, IR, Raman, 195Pt-NMR, FAB-Massenspektrometrie und Rontgenstrukturanalyse charakterisiert. Fur die Bildung der Komplexe wird ein Reaktionsmechanismus durch Ligandenaustausch vorgeschlagen. Der mittlere Pt–Br-Abstand betragt in 1: 2,456 A, in 2: 2,496 A (trans zu Ph), in 3: 2,476 A (trans zu Sb), was auf einen ahnlichen Transeinflus von Ph3Sb und Ph3P hinweist.

Solvent-free aldol condensations: synthesis of ferrocenyldienones

The aldol condensation of ferrocenecarbaldehyde and acetylferrocene with aldehydes and ketones proceeded more efficiently and stereoselectively in the absence of a solvent than in solution. In all the cases, E-configured enones were obtained, which was confirmed by X-ray crystallographic studies of one of the products.

Difluorenylsilane derivatives, a class of compounds exhibiting strong intra- and intermolecular CH⋯π interactions. Crystal and molecular structures of bis(9-methylfluoren-9-yl)dimethylsilane and (9-methylfluoren-9-yl)(fluoren-9-yl) dimethylsilane

The crystal and molecular structures of substituted difluorenyl-(dimethyl)silanes Me 2 Si(CR′R 2 )(CR″R 2 ) (R′=H, R″=Me 1 and R′=R″=Me 2 , CR 2 =fluorenyl) have been determined by X-ray diffraction and compared with the conformations available in the gas phase. 1 and 2 crystallize in the P 2(1)/ m and P 2(1)/ c space groups with the cell parameters: a =7.191 A, b =17.658 A, c =8.982 A, α = γ =90°, β =101.880° ( 1 ) and a =13.132 A, b =7.463 A, c =24.438 A, α = γ =90°, β =99.73° ( 2 ), respectively. Both compounds as well as the unsubstituted parent silane Me 2 Si(CHR 2 ) 2 ( 3 ) exhibit extensive intramolecular and intermolecular CH⋯π interactions leading to supramolecular associations. Gas phase conformations predicted on the basis of AM1 semiempirical molecular orbital calculations support the existence of these intramolecular interactions and correlate well with the temperature dependent proton NMR spectra.

Diorganotin (IV) Heptacoordinated Complexes Containing Pentadentate [N3O2] Ligands Derived From 5-Substituted-Salicylaldehydes and Diethylenetriamine: Synthesis, Characterization, and Molecular Structure

A series of heptacoordinated tin(IV) mononuclear complexes [(R′)2Sn(5-X-saldien)] (X = H, OCH3, NO2) were synthesized by reaction of dimethyl-, di-n-butyl-, di-n-octyl-, and diphenyltin (IV) oxides with the pentadentate Schiff base ligands saldienH2, 5-MeO-saldienH2, and 5-NO2-saldienH2. All of the complexes were characterized by IR, mass spectrometry, and 1H, 13C, and 119Sn NMR spectroscopies, and the spectra display chemical shifts corresponding to a seven-coordinated tin environment. The crystal structures of complexes 2a, 2d, and 4b were determined by X-ray diffraction. The complexes are isostructural and the tin atoms exhibit pentagonal-bipyramidal geometries with the methyl, n-butyl, and phenyl groups occupying the axial positions and the donor atoms from the ligand occupying the equatorial positions. A fluxional behavior was also observed that involves a dissociation-association mechanism of the N-Sn bonds.

Synthesis of ferrocenyl-3,4-dihydro-1H-pyrimidin-2-ones

Methylurea reacts with linear and cyclic α,β-enones of the ferrocene series to yield ferrocenyl-3-methyl-3,4-dihydro-1H-pyrimidin-2-ones characterized by IR and 1 H and 1 3 C NMR spectroscopical data. The structure of 4-ferrocenyl-6-(4-methoxyphenyl)-3-methyl-3,4-dihydro-1H-pyrimidin-2-one is confirmed by X-Ray diffraction analysis.

Structural Diversity of [M{N(SePPh2)2/Se,Se'}2,3] [M(II)=Sn,Pb, Cd, Hg, Se; M(III)=In, Sb, Bi].

The anion [N(SePPh2)(2)](-) forms stable complexes with cations M(II, III); [M(II) = Sn, Se, Cd, Hg; M(III) = In, Sb, Bi], they exhibit a large diversity of structural arrangements around the metal centre. Tin(II) complex crystallizes dimorphically, as square planar and distorted tetragonal pyramidal, Pb(II) is also distorted tetragonal pyramidal, Cd(II) and Hg(II) are tetrahedral, but the Se(II) is square planar. The coordination geometry in the M(III) complexes can be described as a distorted octahedron. The structural situation around the Sb(III) and Bi(III) suggests a stereochemically non-active electron lone pair.

Novel rhodium–antimony bimetallic complexes containing an unusual distibine cis-eclipsed conformation

Rhodium–antimony bimetallic complexes, which represent rare examples of an unusual cis-eclipsed conformation of the phenyl groups in the ligating distibine, are synthesised and characterised by IR, mass spectrometry and X-ray crystallography.

Synthesis and Characterization of New 1,2-Disubstituted Ferrocenyl Bismuthines

Bismuthine Ph2BiFc containing the pendant arm 2-(Me2NCH2)- (1) on ferrocenyl ring was synthesized, and reaction of (1) with CH3I was carried out to obtain the monoammonium salt {[2-(Me3N+CH2)Fc]}BiPh2[I]- (2). Molecular structures of bismuthines (1) and (2) have been determined by X-ray crystallography. Compound (1) does not show hypervalent Bi-N interaction. New 1,2-disubstituted ferrocenyl bismuthines have been characterized by various physicochemical techniques.

Chlorido{1-[(dimethylamino)methyl]ferrocenyl-κ2C2,N}(tri­phenyl­stibine-κSb)palladium(II)

In the title compound, [FePdCl(C5H5)(C8H11N)(C18H15Sb)], obtained by reaction of diphenyl(N,N-dimethylaminomethylferrocenyl)stibine with sodium tetrachloridopalladate(II) in acetone, the PdII atom is coordinated in a slightly distorted square-planar geometry by a C atom of the ferrocenyl ring, and by N, Cl and Sb atoms. The Sb and N atoms are trans to each other.

Synthesis, Characterization and Crystal Structures of 1,2-Disubstituted Ferrocenyl Stibines

New 1,2-disubstituted ferrocenyl stibines containing a -CH2OR pendant arm were synthesized and characterized by various spectral and analytical methods. Nucleophilic substitution of rac-diphenyl[( 2-trimethylammoniomethylferrocen-1-yl)]stibine iodide by methanol produces compound Fc(CH2OMe)SbPh2 (1). The acetylation of diphenyl(2-dimethylaminomethylferrocen-1-yl)stibine by acetic anhydride affords compound Fc(CH2OCOCH3)SbPh2 (2), which on further reaction with sodium hydroxide affords the alcohol Fc(CH2OH)SbPh2 (3). The molecular structures of the stibines 1, 2 and 3 were determined by X-ray crystallography. None of the heterobimetallic compounds containing a -CH2OR arm shows hypervalent interactions in the solid state. By contrast, hypervalent interactions were found in ferrocenyl stibines with a -CH2NR2 pendant arm. Graphical Abstract Synthesis, Characterization and Crystal Structures of 1,2-Disubstituted Ferrocenyl Stibines