Dario M. Frigo

Pentanuclear oxoalkoxide clusters of scandium, yttrium, indium and ytterbium, X-ray crystal structures of [M5(μ5-O)(μ3-OPri)4(μ2-OPri)4(OPri)5] (M = In, Yb)

Abstract Attempts to prepare the metal tri-isopropoxides M(OPri)3 (M = Sc, Y, In, Yb) by various methods always produced the pentanuclear oxoalkoxide clusters [M5(μ5-O)(μ3-OPri)4(μ2-OPri)4(OPri)5] as the stable products. X-ray single crystal diffraction showed (M = In, Yb) the presence of the μ5-oxygen atom bonded in a square pyramidal configuration to five metal atoms which had terminal isopropoxo groups trans to the oxo atom. The μ3- and μ2-isopropoxo groups contribute to the distorted octahedral coordination of each metal atom. The scandium, yttrium and ytterbium clusters could be sublimed in vacuo and gave mass spectra containing pentanuclear cluster ions.The 1H NMR spectra for each compound was consistent with the X-ray crystal structure and variable-temperature studies showed fluxionality in the indium complex.

Growth of epitaxial and highly oriented thin films of cadmium and cadmium zinc sulfide by low-pressure metalorganic chemical vapour deposition using diethyldithiocarbamates

Abstract Thin films of cadmium and cadmium zinc sulfide have been grown by low-pressure metalorganic chemical vapour deposition (MOCVD, 10 −4 Torr, 370–420°C) using the cadmium and zinc complexes of diethyldithiocarbamic acid. The films were typically: specular, hexagonal (from RHEED measurements) and with optical band gaps in the region of 2.4 eV for CdS.

Dimethylindium dialkylamides and organylphosphides, X-ray crystal structure of (Me2InNR2)2 (R = Et, Pri, SiMe3) and (Me2InPBut2)2

The compounds (Me2InNR2)2 (R = Et, Pri, SiMe3 and (Me2InPR2 (R = But, have been prepared. the X-ray crystal structures of all but the diphenylphosphide have been determined, and show them to be pnictido-bridged dimers; the mass spectra of all the compounds indicate that they are dimeric in the vapour phase. The stability of the dialkylamide dimers in the vapour as determined from the mass spectra appears to be in the order NMe2 > NEt2 > NPr2i > N(SiMe3)2, in line with steric effects; the crystal structures showed a slight lengthening of the IN bond in the same order, but the most marked structural variation was shown to be the CC angle which had values of 131, 126, 119 and 109°, respectively. The corresponding value for (Me2InPBu2t)2 was 109°.

Adducts of trimethylindium with amine and phosphine ligands; X-ray crystal structure of Me3InNHCMe2(CH2)3CMe2, Me3InN(CH2CH2)3N and Me3InNHMe(CH2)2NHMeInMe3

Abstract Treatment of trimethylindium diethyletherate separately with a number of amines and a phosphine has given the products Me3InL where L  NH(C6H11)2 (1), NHCHMe(CH 2 ) 3 C HMe (2), NHCMe 2 (CH 2 ) 3 C Me2 (3), N(CH2CH2)3CH (4), N(CH2CH2)3N (5), (CH2NEt)3 (6) and P(NMe2)3 (7). The complexes Me3In-NHMe(CH2)2NHMeInMe3 (8) and Me2InCl[MeNH C(CH) 4 N ] (9) have also been made by direct reaction of Lewis acid etherate and Lewis base. The X-ray crystal structure of 3 shows a longer InN bond (2.50 A) than that found in the crystal structure of 8 (2.38 A); both possess distorted tetrahedral metal environments. The X-ray crystal structure of 5 shows a linear polymer of alternating Me3In and N(CH2CH2)3N units; the Me3In unit is planar and the indium is almost perfectly trigonal bipyramidal and the InN bonds are very long (2.62 A) compared with 3 and 8. Variable temperature 1H NMR studies of 6 show the adduct bond is very labile: rapid exchange between adduct components is occurring even at −70°C.

A penta-indium oxo alkoxide cluster with a central 5-co-ordinate oxygen. Preparation and X-ray crystal structure of (InOPri)5(µ2-OPri)4(µ3-OPri)4(µ5-O)

The X-ray crystal structure of (InOPri)5(µ2-OPri)4(µ3-OPri)4(µ5-O) reveals a square-pyramidal arrangement of indium atoms about a central oxygen; five of the alkoxo groups are terminal, four are µ2 about the basal metals, and four are µ3 about the triangular faces of the pyramid; the geometry about each metal is highly distorted octahedral.

A method for dosing solid sources for MOVPE: excellent reproducibility of dosimetry from a saturated solution of trimethylindium

Abstract A new precursor system for MOVPE of In-containing layers consists of trimethylindium (TMI) in contact with, and dissolved to saturation in, an inert, involatile, liquid solvent. When placed in a conventional bubbler the TMI vapour is entrained by pickup gas bubbling through the resulting solution. Saturation of this solution is maintained by continuous dissolution of excess solid TMI. Dosimetry from 2 sources containing different amounts of solution are shown to be more reproducible than that from TMI alone. The electrical and optical properties of layers grown from the new source are excellent.

The crystal and molecular structure of bis[2-((dimethylamino)methyl)phenyl]cadmium(II)

Abstract The crystal and molecular structure of bis[2-((dimethylamino)methyl)phenyl]cadmium(II) compound is reported. The structure consists of trigonally bipyramidal molecules with a vacant axial site. The vacant site is blocked by an adjacent cadmium atom with a relatively short metal-metal separation of 3.176 A.

The volatilities of organo-indium compounds by Knudsen effusion

The volatilities of some organo-indium compounds have been measured by Knudsen mass loss effusion in the range 10-6 to 10-2 Torr ∗. Graphical plots of 1n(WT12) versus 1/T were obtained; all were linear within experimental error and slopes and intercepts are presented. For [Me2InH(CH2)3CH2]2 a reversible solid-solid phase change was detected via such a plot.

A six-coordinate complex of indium(III) containing trimethylindium bonded to N,N′,N″-triisopropyl-1,3,5-triazacyclohexane

Me3In(PriNCH2)3 has been shown by X-ray crystallographic analysis to be the first example of a six-coordinate indium(III) complex containing trimethylindium bonded to a terdendate nitrogen donor ligand; the In–N bonds [2.776(17) and 2.776(13)A] are the longest In–N bonds measured so far.

The volatilities of some adducts of trimethylindium

Abstract The volatilities of some adducts of trimethylindium with amine and phosphine ligands were measured by the modified entrainment method (MEM). The results indicated that for some adducts both dissociative and undissociative vaporization takes place in the temperature ranges covered.