S. I. Troyanov

Synthesis and characterisation of tin(IV) and organotin(IV) derivatives 2-{((2-hydroxyphenyl)imino)methyl}phenol

Abstract From the interaction of 2-{[(2-hydroxyphenyl)imino]methyl}phenol(salopH2) with tin and organotin(IV) acceptors, the derivatives [SnR3(salopH)] (R=Me or Bun), [SnR2(salop)] (R=Me, Bun, But, Vin or Ph), [SnRX(salop)(solvent)] (R=Me, Bun, Ph or X; X=Cl, Br or I; solvent=CH3OH or H2O), [Sn(salop)2], [R2SnCl2(salopH2)] (R=Me or Bun) have been obtained and characterised. The chelates, containing the Schiff base in mono or dianionic form, are generally stable both in the solid state and in solution, whereas the [SnR2Cl2(salopH2)] adducts slowly decompose in acetone or DMSO yielding [SnR2(salop)] and releasing HCl. All the [SnR2(salop)] and [SnRX(salop)(solvent)] complexes are fluxional in solution. The 119Sn NMR chemical shift is a function of the number of R groups. The X-ray single crystal diffraction study of [SnVin2(salop)] shows the metal to be five-coordinate in a distorted square pyramidal environment, SnC distances being 2.112(2) and 2.113(2) A, SnO 2.117(2) and 2.125(2) A and SnN 2.227(2) A. The whole structure consists of molecular units connected by weak intermolecular SnO interactions. In the complexes [SnX2(salop)(CH3OH)]·CH3OH complexes (X=Cl or Br), the tin atom is found in a strongly distorted octahedral environment with the SnO bond ranging from 1.995(3) to 2.055(2) A. The SnN bond is 2.116(4) A in the bromide and 2.171(3) A in the chloride complex.

Two Isomers of C60F48: An Indented Fullerene

Deflated buckyballs: The single-crystal structure of C60 F48 ⋅2 (mesitylene) revealed the presence of both D3 and S6 isomers in the same crystal. C(sp2 )-C(sp2 ) bonds (1.30 Å) are much shorter than C(sp3 )-C(sp3 ) bonds (1.54-1.63 Å). The C60 cage is characterized by concave areas in the regions of six double bonds. Each double bond is effectively shielded by four F atoms, which accounts for the low reactivity of C60 F48 .

Titanocene-bis(trimethylsilyl)acetylene complexes: effects of methyl substituents at the cyclopentadienyl ligands on the structure of thermolytic products

Abstract The (C5H5−nMenTi[η5-C2(SiMe3)2] (n = 0–5) (1A–1F) complexes were prepared by the reduction of corresponding titanocene dichlorides with magnesium in THF in the presence of bis(trimethylsily)acetylene (BTMSA). All of them were characterized by spectroscopic methods and (C5HMe2Ti[η5-C2(SiMe3)2] (1E) by the X-ray crystal analysis. The complexes decompose at temperatures in the range 100–200°C. Those with n = 0–3 yield (μ-η5 : η5-fulvalene)(di-μ-hydrido)bis (η5-cyclopentadienyltitanium) (2A) and its methylated analogues (2B–2D) whereas BTMSA is released. The crystal structure of 2D showed that the hexamethylfulvalene ligand contains non-methylated carbon atoms in inner alternate positions. Complex 1E afforded a mixture of products. Among them only volatile isomers (η3:η4-1,2-dimethyl-4,5-dimethylcyclopenteny)(η5-tetramethylcyclopentadienyl)titanium (2Ea) and (η3:η4-1,3-dimethyl-4, 5-dimethylenecyclopentenyl)(η5-tetramethylcyclopentadienyl)titanium (2Eb) have been so far isolated as minor products. The C5Me5 comples 1F yields quantitatively (η3:η4-1,2,3-trimethyl-4,5-dimethylenecyclopentyl)(pentamethylcyclopentadienyl)titanium (2F) and BTMSA is hydrogenated to a mixture of cis- and trans-bis(trimethylsilyl)ethene.

Bromination of [60]Fullerene. II. Crystal and Molecular Structure of [60]Fullerene Bromides, C60Br6, C60Br8, and C60Br24

Abstract The crystal and molecular structures of the bromofullerene solvates C60Br6·0.5C6H5Cl·0.5Br2, C60Br8·1.5(o‐C6H4Cl2), C60Br8·Br2, C60Br8·0.5C6H5Br·0.5Br2, and C60Br24·2Br2 have been determined by single crystal X‐ray diffraction. The molecular species C60Br6, C60Br8, and C60Br24 which have idealized C s , C 2v , and T h symmetries, respectively, have several different types of C‒Br and C‒C bonds. A comparison between different solvates of the same bromofullerenes revealed a larger stability of the packing modes for the C60Br6 and C60Br24 solvates, whereas the C60Br8 solvates showed different packing motifs dependent on the nature and amount of the solvent molecules.

Novel, highly symmetrical halogen-centered polynuclear lanthanide complexes: [Cp6Yb6Cl13](-) and [Cp12Sm12Cl24]

If THF is removed from the complexes [CpLnCl2(thf)3] (Cp=C5H5, Ln=Sm, Yb), halogen-centered polynuclear complexes are formed. [{CpSmCl2}12] displays an icosahedral arrangement of the 12 Sm atoms with 20 Cl atoms in the “outer envelope” and four further Cl atoms within the icosahedron (see structure on the right). The partially desolvated [CpYbCl2]⋅1/3 THF consists of trinuclear cations [Cp3Yb3Cl5(thf)3]+ and octahedral anions [Cp6Yb6Cl13]−.

Structure and volatility of copper complexes containing pyrazolyl-based ligands

Abstract Volatility studies, electrospray mass spectra and IR in vapour phase were carried out for a series of Cu(I) and Cu(II) complexes containing anionic pyrazole-based ligands such as 4-acyl-5-pyrazolonates and poly(pyrazolyl)borates. The volatility has been related to structural features and molecular parameters of the copper complexes. The crystal structures of [Cu(Q′)2(bipy)]·(acetone)1.5 (Q′=1-phenyl-3-methyl-4-benzoyl-pyrazolon-5-ato, bipy=2,2′-bipyridyl) and [Cu(QF)2(phen)]·EtOH (QF=1-phenyl-3-methyl-4-trifluoroacetyl-pyrazolon-5-ato, phen=1,10-phenanthroline), have been also determined. In these complexes the copper atom is in a tetragonally distorted octahedral arrangement of the four O-atoms of pyrazolones with N2-donor ligand in equatorial position. Two sets of CuO distances, the longer being in axial positions, have been found. XRD data of films obtained from metal organic chemical vapour deposition MOCVD experiments on [Cu(poly(pyrazolyl)borate)(PR3)] complexes have also been reported.

The reactivity of hydrotris(3-methyl-2-thioxo-1-imidazolyl)borate (Tm) towards organotin(IV) acceptors. An unprecedented monodentate coordination mode of Tm ligand

Abstract The reaction between RSnCl3 (R=Me, Bun or Ph), R2SnCl2 (R=Me, Et, Bun or Ph) and R3SnCl (R=Me, Bun, Ph or cy) acceptors and equimolar amounts of hydrotris(3-methyl-2-thioxo-1-imidazolyl)borate potassium salt K[Tm] yields the complexes [(Tm)RSnCl2], [(Tm)R2SnCl] and [(Tm)R3Sn], respectively. The NMR data (1H, 119Sn) showed the mono- and di-organotin derivatives to be five-coordinated in solution, whereas the triorganotin(IV) derivatives are tetrahedral both in solution and in the solid state, as confirmed by X-ray crystallography. The X-ray crystal structure of [(Tm)cy3Sn] is the first example of a complex containing the Tm-ligand coordinated in monodentate fashion, with the tin in a quasi-regular tetrahedral environment and SnS bond being 2.478(1) A.

Synthesis and x-ray crystal structures of tetrakis-(2,2,6,6-tetramethylheptane-3,5-dionato)bis(2,2′-bipyridyl)dibarium Ba2(thd)4(bipy)2 and catena-[dodecakis(2,2-dimethylpropanoato)bis(2,2,6,6-tetramethylheptane-3,5-dionato)tetra(pyridine)tetra(aqua) heptabarium] pyridine solvate {Ba7(piv)12(thd)2(py)4(H2O)4·2py}

Abstract Two new volatile mixed ligand barium complexes have been synthesized and their X-ray crystal structures determined. Ba2(thd)4(bipy)2 (1) consists of dimeric molecules; with two barium atoms linked by four bridging BaOBa bonds. The structure of {[Ba7(piv)12(thd)2(py)4(H2O)4]·2py} (2) contains Ba3 units and separate Ba atoms which are connected into infite chains through BaOBa bridges.

Ligation properties of N-substituted imidazoles: synthesis, spectroscopic and structural investigation, and behaviour in solution of zinc(II) and cadmium(II) complexes

Abstract Novel zinc(II) and cadmium(II) derivatives of 1-methyl- (L′) and 1-benzyl-imidazole (L″) of the type 1:1 [(L)MX2] (L = L″, M = Zn, X = 4-acetyl-1-phenyl-3-methylpyrazolonato (Q″), 4-benzoyl-1-phenyl-3-mrthylpyrazol-5-onato (Q′) or 4-benzoyl-1,3-dimethylpyrazol-5-onato (Q∗); L= L″, M = Cd, X = Q′or Q∗, 2:1 [(L)2MX2]·y(H2O) (L = L′, M = Zn, X = Cl, Br, I, CH3CO2, Q′, Q″ or Q∗; L = L′, M = Cd, X = I, CH3CO2, Q′ or Q∗; L = L″, M = Zn, X = Cl, Br, I; L = L″, M = Cd, X = I or Q″), 3:1 [(L″)3MX2]·y(H2O) (M = Zn, X = CF3CO2, NO3 or BF4; M = Cd, X = NO3), 4:1 [(L′)4Zn]X2·y(H2O) (X = NO3 or BF4), 5:1 [(L′)5Zn]X2·y(H2O) (X = ClO4 or CF3CO2) 6:1 [(L′)6Zn]X2·y(H2O) (L = L′, M = Zn, X = CF3SO3; L = L′, M = Cd, X = NO3, ClO4 or BF4; L = L″, M = Cd, X = ClO4 or BF4), 4:3 [(L″)4(CdX2)3] (X = Cl or Br) and finally 5:3 [(L′)5(CdBr2)3] have been prepared and characterized by IR and far-IR data, conductivity, 1H NMR and in some cases also with 113Cd NMR spectroscopy. The 4,7-dimethyl-1,10-phenanthroline (Me2Phen) and 2,2′-bipyridine (Bipy) displace all the 1-methylimidazole donors from [(L′)5Zn](ClO4)2·H2O or [(L′)6Cd(ClO4)2 diethyl ether suspension, yielding the trischelate complexes [(Me2Phen)3M](ClO4)2 and [(Bipy)3M](ClO4)2 (M = Zn or Cd). On the other hand, 2-benzoylpyridine (Bzpy) and 4,7-diphenyl-1,10-phenanthroline (Ph2Phen) react with [(L′)5Zn](ClO4)2·H2O yielding the mixed ligands complexes [(Bzpy)2(L′)2Zn](ClO4)2 and [(Ph2Phen)2(L′)Zn](ClO4)2 respectively. From the reaction of Ph2Phen with [(L′)6Cd(ClO4)2 the ionic compound [(Ph2Phen)3Cd](ClO4)2 is obtained. The structure of [(L″)3Cd(NO3)2] was determined by X-ray single crystal diffraction: the Cd atom exhibited a distorted trigonal bipyramidal geometry, involving two O-monodentate nitrato groups in axial position and three 1-benzylimidazole ligand in the equatorial positions. 113Cd NMR solution data carried out on selected soluble pyrazolonato, carboxylato and nitrato derivatives indicated five- or six-coordinate N3CdO2, N4CdO2, N2CdO4 and NCdO4 species in solution.

New oligomeric mixed ligand barium chelates containing additional anionic ligands

Abstract The mixed ligand complex [Ba5(thd)9Cl(H2O)7] (I) was obtained by recrysallization in the system BaCl2—Nathd—EtOH. Using Hthd (2,2,6,6-tetramethylheptanedione-3,5), containing a small amount of pivalic acid (Hpiv) and a neutral Lewis base (pyridine), two complexes [Ba6(thd)4(piv)8(py)4](py)2 (II) and Na2Ba7(thd)2(piv)14(py)4(H2O)2 (III) have been isolated. An X-ray study revealed that I consists of the pentanuclear species, barium atoms forming a distorted square pyramid, with the chloride being incorporated. In structures II and III, Ba3 triangles are linked into a hexanuclear unit (II) or into an infinite chain (III) through the bridging piv ligands.