M. Helliwell

Iron Thiobiurets: Single-Source Precursors for Iron Sulfide Thin Films

The iron(III) complexes of several 1,1,5,5-tetraalkyl-2-thiobiurets [Fe(SON(CN(i)Pr(2))(2))(3) (1), Fe(2)(μ-OMe)(2)(SON(CNEt(2))(2))(2) (2), Fe(SON(CNEt(2))(2))(3) (3), and Fe(SON(CNMe(2))(2))(3) (4)] have been synthesized, and the single-crystal X-ray structures of 1, 2, and 4 have been determined. The magnetic properties of complex 2 as a function of the temperature and field were studied. Thermogravimetric analysis of complexes 1-4 showed the decomposition in one major step to iron sulfide residues. All four complexes were used as single-source precursors for the deposition of iron sulfide thin films by aerosol-assisted chemical vapor deposition. Complex 1 gave hexagonal troilite FeS films with a small amount of tetragonal pyrrhotites Fe(1-x)S at 300 °C, whereas only troilite FeS was deposited at 350, 400, or 450 °C. Complexes 2 and 3 deposited a mixture of hexagonal troilite FeS and cubic pyrite FeS(2) films at all temperatures. Complex 4 deposited very thin films of FeS at all temperatures as troilite. Scanning electron microscopy images of the films deposited from all complexes showed that the morphology consisted of plates, granules, rods, and sheets like crystallites. The size and shapes of these crystallites were dependent on the growth temperature and the precursor used. This is the first time that iron(III) thiobiuret complexes have been used as single-source precursors for iron sulfide thin films.

Phthalocyanine-centred aryl ether dendrimers with oligo(ethyleneoxy) surface groups

Abstract The synthesis of phthalocyanine-centred aryl ether dendrimers possessing oligo(ethyleneoxy) surface groups is described. These materials are soluble in polar protic solvents. The tendency of the non-polar phthalocyanine core to aggregate in such solvents is eliminated by placing the dendritic substituents at the axial sites, however, aggregation is not reduced by peripheral dendritic substitution.

An All-Vanadium(III) Hexametalate Lindqvist Structure and Its Chromium and Iron Analogues

The hexametalate Lindqvist ion {M6O19} n , comprising a superoctahedron of condensed {MO6} fragments, is one of the classic structures in polyoxometalate chemistry and is known for Mo, W, Nb and Ta. Although the naked vanadium clusters are not known, the all-vanadium(V) form has been stabilised by capping with organometallic fragments. Replacement of some or all of the twelve m-oxides with malkoxides, thus reducing the charge of the core (a common route to stabilising polyoxovanadates), can stabilise reduced V forms and Zubieta and co-workers isolated the fully reduced, all-V hexametalate by using tris-alkoxides in [(VIV6O)6OACHTUNGTRENNUNG{EtC ACHTUNGTRENNUNG(CH2O)3}4]2 (1 , Figure 1). Here we report the isolation of the six-electron further reduced (i.e., the all-vanadium ACHTUNGTRENNUNG(III)) hexavanadate by formally replacing {VO} with the {VCl} fragment. Furthermore, we can extend this chemistry to the analogous Cr and Fe species. This series of hexametalate structures is attractive for magnetic studies because 1) families of isostructural high-nuclearity clusters for several different metal ions (here spanning d, d, d and d) are very rare and 2) the cluster anions approximate very closely to Td symmetry and this is a rare example in which an analytical solution exists to the spin Hamiltonian for a large cluster. Solvothermal reaction of [VCl3 ACHTUNGTRENNUNG(thf)3] with pyridine (1:2) in MeCN at 100 8C, followed by addition of the triol MeCACHTUNGTRENNUNG(CH2OH)3 (2 equiv) and further heating at 150 8C produced crystalline [(VCl)6O ACHTUNGTRENNUNG{MeC ACHTUNGTRENNUNG(CH2O)3}4] ACHTUNGTRENNUNG(Hpy)2 (2). Complex 2 crystallises in the cubic space group P4̄3n. The [(VCl)6OACHTUNGTRENNUNG{MeC ACHTUNGTRENNUNG(CH2O)3}4]2 (2 ) anion has crystallographic C3v point symmetry (two unique metal ions; Figure 1 and Table 1), but approximates very closely to Td (0.1% deviation, from comparison of edge lengths of the tetrahedron defined by the four methyl groups). The anion structure is identical to that found by Zubieta et al. , 1 , but with replacement of all {VO} with {VCl} (replacement of MeCACHTUNGTRENNUNG(CH2OH)3 by EtC ACHTUNGTRENNUNG(CH2OH)3 in the synthesis gave the directly analogous [(VCl)6O ACHTUNGTRENNUNG{EtCACHTUNGTRENNUNG(CH2O)3}4] ACHTUNGTRENNUNG(Hpy)2 (3)). A superoctahedron of six V ions (each with a {VO5Cl} coordination sphere) is centred on a m6-oxide (O1), with alternate faces of the octahedron capped by the four m,m,m-MeC ACHTUNGTRENNUNG(CH2O)33 ligands (defining a tetrahedron). Hence, each RC ACHTUNGTRENNUNG(CH2O)33 replaces three moxides from the parent Lindqvist structure. All of the vanadium ions have a terminal chloride and are V as confirmed by the charge balance (there are two pyridinium cations), bond valence sum calculations (bond valence sum= 3.12 and 3.10) and magnetic properties (see below). In comparison with the V structure 1 (and related V structures) the {V6O} core in 2 2 has contracted in size despite reduction of the metal ions (V (m6)O=2.315(2) and 2.191(4) for 1 and 2 (mean value), respectively). The longer V O1 bond length in 1 presumably reflects the stronger trans influence of terminal oxide (compared with [a] L. J. Batchelor, Dr. R. Shaw, S. J. Markey, Dr. M. Helliwell, Prof. E. J. L. McInnes School of Chemistry, The University of Manchester Manchester M13 9PL (UK) Fax: (+44) 161-275-4616 E-mail : eric.mcinnes@manchester.ac.uk Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/chem.201000222. Table 1. Selected bond lengths and angles for 2, 4 and 5.

A new synthesis of InAs quantum dots from [tBu2AsInEt2]2

The dimer [tBu2AsInEt2]2 has been synthesized and characterized by spectroscopic and X-ray crystallographic methods. This complex has been used as a precursor for the synthesis of InAs nanoparticles in hexadecylamine (HDA) at 280 °C. This is the first time that a single-source organometallic precursor has been used to grow InAs nanoparticles. The particles show a considerable blue shift in their optical spectra as compared to the parent bulk materials. The photoluminescence had an emission maximum at the band edge and showed a significant increase in the quantum yield as compared to those reported previously. A PXRD pattern showed the particles to be cubic InAs and HRTEM confirmed the crystalline nature of the dots with an average diameter of ca. 8.8 nm. EDAX measurements and microanalysis showed the stoichiometry of InAs nanoparticles to be close to 1 : 1.

Co(II) and Cu(II) complexes of 2,4-diamino-5-(3,4,5-trimethoxybenzyl)pyrimidine

The Co(II) and Cu(II) complexes of 2,4-diamino-5-(3,4,5-trimethoxybenzyl)pyrimidine (trimethoprim) were synthesized and characterized by elemental analysis, UV-Vis and IR spectroscopy, magnetic susceptibility measurements, EPR (Cu complexes) and single crystal X-ray studies. The molecular structures of the compounds consist of dimeric metal ions in distorted octahedral environments, bridged with four acetate ions and each metal ion coordinated to one trimethoprim through the pyrimidinyl nitrogen atom.

4-Benzoyl-2-chloro-6-phenylpyrimidine

In the title compound, C 17 H 11 ClN 2 O, the molecule contains an essentially planar pyrimidine ring with the 4- and 6-positions substituted by benzoyl and phenyl groups, respectively. The phenyl ring and the planar part of the benzoyl moiety form dihedral angles of 12.3 (1) and 62.1 (1)°, respectively, with the pyrimidine ring. The two phenyl rings are inclined at an angle of 130.0 (1)° with respect to one another.

N,N'-Dicyclohexyl-N-[4-(1H-indol-3-yl)butanoyl]urea.

The title compound, C(25)H(35)N(3)O(2), is a novel urea derivative. Pairs of intermolecular N-H...O hydrogen bonds join the molecules into centrosymmetric R(2)(2)(12) and R(2)(2)(18) dimeric rings, which are alternately linked into one-dimensional polymeric chains along the [010] direction. The parallel chains are connected via C-H...O hydrogen bonds to generate a two-dimensional framework structure parallel to the (001) plane. The title compound was also modelled by solid-state density functional theory (DFT) calculations. A comparison of the molecular conformation and hydrogen-bond geometry obtained from the X-ray structure analysis and the theoretical study clearly indicates that the DFT calculation agrees closely with the X-ray structure.

Imino-bis(diisopropylphosphine chalcogenide) complexes of arsenic, antimony and bismuth. Synthesis, CVD studies and X-ray structure of M[N(EPiPr2)2]n(E = Se, S; M = As, Sb, Bi)

Bismuth, and antimony complexes of imino-bis(diisopropylphosphine chalcogenide) ligands, M[N(EPiPr2)2]n (E = S or Se; M = Bi and Sb) have been prepared by the reaction of the sodium salt of NH(EPiPr2)2 (E = S or Se) with the appropriate group 15 metal salt in methanol. The complexes are monomeric in the solid state and air stable. The crystal structures of Bi[(iPr2PS)2N]3 and Sb[(iPr2PS)2N]3 have been determined by X-ray diffraction. The compounds are isostructural, with distorted octahedral coordination geometries and extended P–Se bonds. The bismuth compounds have been used in both AA-MOCVD and LP-MOCVD to deposit thin films of bismuth chalcogenide.

Methyl (3aR,4R,7S,7aS)-1,3-dioxo-7-phenyl-1,3,3a-4,7,7a-hexahydro-4-isobenzofurancarboxylate

The structure of the title compound, C 16 H 14 O 5 , has been determined by X-ray diffraction. The molecule contains four chiral centres; both enantiomers are present in the crystal as a result of the centrosymmetric space group. As expected for a Diels-Alder adduct, the ring-junction H atoms display a cis relationship. The conformation of the six-membered ring is an ideal boat, whereas the five-membered ring is significantly flattened

The Correct Structures of the ortho-Cyclized Products in the Cycloalkylations of 1-m-Methoxybenzyl-4,4a,5,6,7,8-Hexahydronaphthalen-2(3H)-One and 1-m-Methoxybenzyl-Octalins : X-Ray Structure Determination of (±)-4-Methoxy-9a-Carbamorphinan-16-One

Abstract The previously assigned (ref.1) ortho-cycloalkylated product from the reaction of 1 and 2 respectively, with ortho-phosphosphoric acid and polyphosphoric acid, has been corrected to (±)-4-methoxy-9a-carbamorphinan-16-one (6) and the respective ether 7 by a single crystal X-ray structure determination of 6.