Platinum ω-Alkenyl Compounds as Chemical Vapor Deposition Precursors: Synthesis and Characterization of Pt[CH₂CMe₂CH₂CH═CH₂]₂ and the Impact of Ligand Design on the Deposition Process

Abstract

We describe the synthesis and characterization of three platinum­(II) ω-alkenyl complexes of stoichiometry Pt­[CH2CMe2(CH2) x CHCH2]2 where x is 0, 1, or 2, as well as some related platinum­(II) compounds formed as byproducts during their synthesis. The ω-alkenyl ligands in all three complexes, cis-bis­(η1,η2-2,2-dimethylbut-3-en-1-yl)­platinum (2), cis-bis­(η1,η2-2,2-dimethylpent-4-en-1-yl)platinum (3), and cis-bis­(η1,η2-2,2-dimethylhex-5-en-1-yl)­platinum (4), bind to Pt by means of a Pt–alkyl sigma bond at one end of the ligand chain and a Pt–olefin pi interaction at the other; the olefins reversibly decomplex from the Pt centers in solution. The good volatility of 3 (10 mTorr at 20 °C), its ability to be stored for long periods without decomposition, and its stability toward air and moisture make it an attractive platinum chemical vapor deposition (CVD) precursor. CVD of thin films from 3 shows no nucleation delay on several different substrates (SiO2/Si, Al2O3, and VN) and gives films that are unusually smooth. At 330 °C in the absence of a reactive gas, the precursor deposits platinum containing 50% carbon, but in the presence of a remote oxygen plasma, the amount of carbon is reduced to below the Rutherford backscattering spectroscopy (RBS) detection limit without affecting the film smoothness. Under hot wall CVD conditions at 250 °C in the absence of a co-reactant, 72% of the carbon atoms in 3 are released as hydrogenated products (largely 4,4-dimethylpentenes), 22% are released as dehydrogenated products (all of which are the result of skeletal rearrangements), and 6% remain in the film. Some conclusions about the CVD mechanism are drawn from this product distribution.

Investigations into the structure, reactivity, and AACVD of aluminium and gallium amidoenoate complexes

“…Nuclear magnetic resonance (NMR) data were recorded in either CDCl 3 or C 6 D 6 (obtained from sigma, dried on sieves and stored under an inert atmosphere) using a Bruker Avance 300, Bruker Avance Neo 500 or Bruker Avance Neo 700 MHz instrument at ambient temperature. 1 H and 13 C{ 1 H} NMR assignments were confirmed by 1 H-1 H (COSY and NOESY) and 1 H-13 C (HSQC and HMBC) experiments where necessary. Mass spectra were obtained using a Micromass 70-SE spectrometer using electrospray chemical ionization in the positive mode (ESI + ).…”

“…Yield: 16.2g, 77 %. 1 H NMR δ/ppm (500 MHz, CDCl 3 ): 9.86 (s, 1H, NH ), 7.29 (t, 1H, 3 J HH = 7.7Hz, Ar-H para ), 7.17 (d, 2H, 3 J HH = 7.6Hz, Ar-H meta ), 4.68 (s, 1H, C=CHC), 4.17 (q, 2H, 3 J HH = 7.1 Hz, OCH 2 CH 3 ), 3.10 (sept, 2H, 3 J HH = 6.9 Hz, CH(CH 3 ) 2 ), 1.63 (s, 3H, CH 3 C=C), 1.31 (t, 3H, 3 J HH = 7.1 Hz, OCH 2 CH 3 ), 1.22 (d, 6H, 3 J HH = 6.9 Hz, CH(CH 3 ) 2 ), 1.15 (d, 6H, 3 J HH = 6.8 Hz, CH(CH 3 ) 2 ).…”

“…Final attempts at abstracting the Cl-atom from the main group centres involved employing Jones' low-valent Mg(I) complex, 47 [Mg(BDI Mes )] 2 (Mes = mesityl), in order to either reduce the complexes to form [(AME) 2 M-M(AME) 2 ] dimers or by installing [M-Mg] (M= Al, Ga) bonds. At elevated temperatures, these reactions resulted in some AME-complex decomposition (as evidenced by 1 H NMR experiments -see Supporting Information). As functionalization of the chloride to a hydride was not achieved, the reactivity study to investigate whether a group 13-hydride synthon could be used to synthesize a metal hydride bis-amidoenoate complex (Scheme 3).…”

“…Journal Name 10 | J. Name., 2012, 00, [1][2][3] This journal is © The Royal Society of Chemistry 20xx…”

“…In recent decades, precursor design and synthesis has become increasingly important for the deposition of functional materials. [1][2][3][4] Specifically, the customization of precursors which deliver specific properties demanded by the deposition technique such as volatility or solubility have placed 'designer' precursors center-stage for a wide-range of material deposition techniques, including aerosol-assisted chemical vapor deposition (AACVD), [4][5][6][7][8] spin-coating, [9][10][11] or by ink deposition. [12][13][14] Recently, investigations into the structural parameters of metal-containing molecular precursors have been carried out in order to probe relationships between a precursor's molecular geometry (dictated by the bonding modes of the ligands bound to the metal) and their suitability for deposition.…”