Jamie F. Bickley

Novel Mononuclear Alkoxide Precursors for the MOCVD of ZrO2 and HfO2 Thin Films

Thin films of ZrO 2 and HfO 2 have been deposited by liquid injection metal-organic (MO)CVD using a range of new alkoxide precursors, [Zr(O t Bu) 2 (mmp) 2 ] (1), [Hf(O t Bu) 2 (mmp) 2 ] (2), [Zr(mmp) 4 ] (3), and [Hf(mmp) 4 ] (4): (mmp = 1-methoxy-2-methyl-2-propanolate, OCMe 2 CH 2 OMe). The complexes are mononuclear and volatile, and are significantly less reactive to air and moisture than existing Zr and Hf alkoxide precursors such as [Zr(O t Bu) 4 ] and [Hf(O t Bu) 4 ]. The ZrO 2 and HfO 2 films were grown over a wide range of substrate temperatures (350-650 °C), and analysis by laser Raman spectroscopy shows that the films were deposited in the thermodynamically stable α- or monoclinic phase.

Fluoroalkylated N-heterocyclic carbene complexes of palladium

Abstract Fluoroalkylated N-heterocyclic carbene complexes of palladium have been synthesized from imidazolium salts and Pd(OAc)2. The analogous carbene complexes bearing long alkyl chains have also been prepared. The formation of these carbene complexes proceeds via an intermediate binuclear species, which has been isolated. Complexes such as these may find applications in catalysis in supercritical CO2 (scCO2).

Structural effects on sigmatropic shifts in heteroaromatic allyl ethersElectronic supplementary information (ESI) available: selected crystal data for compound 7. See http://www.rsc.org/suppdata/p1/b1/b102674g/

In contrast to the known thermal, exclusively [3,3], O- to N- rearrangement of allyl groups in phenyltetrazoles (1, Scheme 1), the comparable migration of the allyl group in pseudosaccharyl ethers (3; Scheme 2) has been shown to proceed through both [1,3]- and [3,3]-mechanisms, 4, 5; for the pseudosaccharyl derivative of the natural product myrtenol (6; Scheme 3) only the product 7 of a [1,3]-shift has been observed; crystallographic data and theoretical calculations provide an explanation of this ease of [1,3]-isomerization and the observed selectivity as being due to conformational constraints and electronic factors.

Crystal Structure of Bi(OCMe2CH2OMe)3 and Its Use in the MOCVD of Bi2O3

The crystal structure of the volatile bismuth alkoxide tris(-methoxy-2-methyl-2-propanolato)bismuth(III), Bi(OCMe 2 CH 2 OMe) 3 , 1, has been determined by single crystal X-ray diffraction (XRD). The complex is mononuclear, containing a six-coordinate Bi III atom in a distorted octahedral environment. Using a solution of 1 in heptane, thin films of bismuth oxide have been deposited by liquid injection metal-organic (MO) CVD. Deposition was carried out over a wide range of substrate temperatures (250-550°C) and, using Auger electron spectroscopy (AES), films were shown to be pure bismuth oxide (Bi 2 O 3 ) with no detectable carbon.

Atomic layer deposition of ZrO2 thin films using a new alkoxide precursor

Abstract Zirconium oxide thin films were grown by atomic layer deposition using a new type of Zr alkoxide: [Zr(O t Bu) 2 (dmae) 2 ] 2 (dmae is dimethylaminoethoxide). Water was used as the oxygen source. The films grown at 190–240 °C were amorphous, and the films grown at 290–340 °C were nanocrystalline. The highest refractive index of the films was 2.08 at a wavelength of 580 nm. The permittivity of a film grown at 240 °C was 25.

Novel mononuclear zirconium and hafnium alkoxides; improved precursors for the MOCVD of ZrO2 and HfO2

The novel complexes [Zr(OBut)2(OCMe2CH2OMe)2] (1) and [Hf(OBut)2(OCMe2CH2OMe)2] (2) are mononuclear and volatile, and are highly promising precursors for the deposition of zirconium dioxide and hafnium dioxide thin films by metalorganic chemical vapour deposition (MOCVD).

Synthesis and crystal structures of dimethylaminoethanol adducts of Ni(II) acetate and Ni(II) acetylacetonate. Precursors for the sol–gel deposition of electrochromic nickel oxide thin films

The reaction between N,N-dimethylaminoethanol (dmaeH) and nickel(II) acetylacetonate, [Ni(acac)2]3 or Ni(II) acetate tetrahydrate, [Ni(CH3CO2)2(H2O)4] yields the new complexes [Ni(acac)2(dmaeH)] (1) and [Ni(CH3CO2)2(dmaeH)2] (2). Complexes (1) and (2) are mononuclear, containing six-coordinate Ni(II) atoms in slightly distorted octahedral environments. Complex (1) contains two bidentate and chelating acetylacetonate groups with a chelating dmaeH ligand. Complex (2) contains two monodentate acetate groups in a cis configuration and two chelating dmaeH ligands. Both complexes dissolve readily in dmaeH to form stable solutions, and are good precursors for the deposition of NiO thin films by sol–gel techniques. (1) and (2) were successfully used to grow electrochromic NiO thin films on conductive glass substrates. The surface morphology of the films was characterised by scanning electron microscopy (SEM) and atom force microscopy (AFM). The thin film performances were characterised by means of optical (transmittance) and electrochemical (cyclic voltammetry) methods. Upon cycling, the NiO thin films switch from brown to transparent in a reversible way exhibiting anodic electrochromic performance.

Asymmetric epoxidation of a geminally-disubstituted and some trisubstituted enones catalysed by poly-l-leucine

Abstract Epoxidation of a range of enones derived from tetralone or related cyclic ketones, employing poly- l -leucine, urea–H 2 O 2 and DBU in iso -propyl acetate is reported. The corresponding epoxides were isolated in 63–85% yield and 59–96% ee.

Deposition of HfO2 and ZrO2 films by liquid injection MOCVD using new monomeric alkoxide precursors

Thin films of ZrO2 and HfO2 have been deposited by liquid injection MOCVD using the new alkoxide precursors [Zr(OBut)2(dmop)2] (1) and [Hf(OBut)2(dmop)2] (2) [dmop = 2-(4,4-dimethyloxazolinyl)-propanolate]. The crystal structures of 1 and 2 have been determined, and they are shown to be six-coordinate monomeric complexes. They are volatile, and are significantly less reactive to air and moisture than existing Zr and Hf alkoxide precursors such as [Zr(OBut)4] and [Hf(OBut)4]. The ZrO2 and HfO2 thin films were deposited over substrate temperatures ranging from 350–550 °C. Analysis by X-ray diffraction shows that the films were deposited in the thermodynamically stable α- or monoclinic phase, and Auger electron spectroscopy shows that the ZrO2 and HfO2 films are non-stoichiometric and that carbon (1.9–8 at%) was present in the oxide films.

Diastereoselective synthesis of aziridines from (1R)-10-(N,N-dialkylsulfamoyl)isobornyl 2H-azirine-3-carboxylates

Reaction of the chiral azirine 1a with nucleophiles and dienes is described. Thiols, heteroaromatic nitrogen compounds and phenylmagnesium bromide add to the azirine 1a to give functionalised aziridines 2/3a–h. X-Ray crystal structures for the products 3e and 3g have been obtained. Diastereodifferentiation of the two faces of the azirine 1a is observed in most cases, but only thiophenol gives a single diastereomer (2a). Most mixtures of diastereomers were separated by dry flash chromatography. Benzylamine produced a dimer of the original azirine 1a, compound 9. Representative conjugated dienes (cyclopentadiene, furan and open chain dienes) were added to the chiral azirine 1a. Only poor selectivities were observed. The selectivity was not significantly enhanced in the cycloaddition of cyclopentadiene to the more bulky azirine 1b.