The structure of bis(1,1,1,5.5,5-hexafluoro-2,4. pentadionato) copper(II) as determined by gas phase electron diffraction

Ligand Coordination in Bis(β-diketonato) d Metals: The Mn(II) Case of D2 h versus D2 d Symmetry

The structure of free manganese(II) bis-acetylacetonate [Mn(acac)₂] was determined experimentally by gas-phase electron diffraction. The vapor at 197(5) °C is composed of a single conformer of Mn(acac)₂ in D_{2 d} symmetry with a central structural motif of an elongated MnO₄ tetrahedron with a Mn-O distance ( r_e) of 2.035(5) Å and a bond angle in chelate rings (∠O-Mn-O) of 89.4(6)°. This result contradicts the predicted planar structure of the MO₄ moiety ( D_{2 h}) with a short Mn-O distance ( r_e) of 1.771 Å from a MC(5i5)QDPT2 calculation. From these findings and by comparison with data from the literature, we conclude that in general in bis(β-diketonato) coordination compounds of d metals there is a perpendicular arrangement of the two ligands for d⁰, d⁵, and d¹⁰ coordination centers and a planar arrangement ( D_{2 h}) for others.

Organometallic Chemical Vapor Deposition of Copper from a New Organometallic Precursor

Thin copper films have been grown on a variety of substrates using Cu(nona-F)2, (bis[4-(2,2,2-trifluoroethyl)imino-1,1,1,5,5,5-hexafluoro-2-pentanonato] copper(II)), a new volatile organometallic copper precursor, and the results are compared with those obtained using copper(II) betadiketonates. Copper films were grown in a cold wall reactor at reduced pressure at temperatures between 270°C and 350°C. For Cu(nona-F)2, films which are pure as determined by Auger electron spectroscopy and have a resistivity of 2.1 micro-ohm cm were deposited at temperatures above 270°C, 40°C lower than was possible using Cu(hfac)2. At low deposition temperatures, Cu(nona-F)2 shows some selectivity towards silicon oxide surfaces in preference to metals. The effects of CVD process parameters on the deposition rate and microstructure of the films were studied with a designed experiment and were statistically modeled. Deposition rates up to 70 nm/min were measured. The standard enthalpy of vaporization of Cu(nona-F)2 was found to be 9.6 kcal/mol.

Structures of anhydrous and hydrated copper(II) hexafluoroacetylacetonate

Crystal structure analyses are reported for anhydrous copper(II) hexafluoroacetylacetonate (Cu(hfac)(2)) and for two of its hydrates. The anhydrous compound (Cu(hfac)(2), 1: P1; at 100 K, a = 5.428(1), b = 5.849(1), c = 11.516(3) A; alpha = 81.47(2), beta = 74.57(2), gamma = 86.96(2) degrees; Z = 1) contains centrosymmetric square-planar complexes with close intermolecular Cu.F contacts. The geometry of the complex is similar to that previously reported for Cu(hfac)(2).toluene. The monoaquo compound (Cu(hfac)(2)(H(2)O), 2: P2(1)/c; at 100 K, a = 10.8300(8), b = 6.5400(6), c = 21.551(3) A; beta = 90.282(8) degrees; Z = 4) consists of square-pyramidal molecules with apical H(2)O ligands, and close-lying F atoms in the sixth coordination sites. The major difference between this structure and the two other polymorphs previously reported is the nature and direction of hydrogen bonds. The yellow-green solid formed from Cu(hfac)(2) with excess H(2)O is identified as the trihydrate. In crystalline form it is the previously unreported [trans-Cu(hfac)(2)(H(2)O)(2)].H(2)O (3: P1; at 150 K, a = 8.3899(3), b = 9.6011(3), c = 11.4852(4) A; alpha = 72.397(2), beta = 79.161(2), gamma = 87.843(2) degrees; Z = 2). There is no conclusive evidence in favor of any solid with the composition Cu(hfac)(2).2H(2)O.

Syntheses, Structures, and Thermal Behavior of Cu(hfacac) Complexes Derived from Ethanolamines

A series of novel precursors for MOCVD of metallic copper have been synthesized and structurally characterized. These precursors are composed of Cu(hfacac)(2), which serves as a volatile source of Cu, and amino alcohols, which act as reductants and anchor firmly to the copper center through the amine unit. In some cases, a proton transfer from the coordinated alcohol to the hfacac ligand results in the formation of an alkoxide unit and the release of the free Hhfacac. Metallic copper films can be deposited by MOCVD at 300 degrees C without any external reductant. Crystal data: Cu(hfacac)(2).C(7)H(8) (-103 degrees C), a = 6.510(6) Å, b = 8.594(7) Å, c = 18.478(15) Å, orthorhombic space group Pmnn, Z = 2; Cu(hfacac)(2)(H(2)NCH(2)CH(2)OH) (-158 degrees C), a = 13.145(1) Å, b = 13.418(1) Å, c = 11.245(1) Å, alpha = 110.39(1) degrees, beta = 99.12(1) degrees, gamma = 97.90(1) degrees, triclinic space group P&onemacr;, Z = 4; [Cu(hfacac)(Me(2)NCH(2)CH(2)O)](2) (-153 degrees C), a = 9.259(2) Å, b = 12.011(3) Å, c = 6.304(1) Å, alpha = 91.19(1) degrees, beta = 106.66(1) degrees, gamma = 74.83(1) degrees, triclinic space group P&onemacr;, Z = 1; Cu(hfacac)[N(CH(2)CH(2)OH)(2)(CH(2)CH(2)O)].MeOH (-168 degrees C), a = 10.075(4) Å, b = 8.611(4) Å, c = 19.259(9) Å, beta = 99.82(2) degrees, monoclinic space group P2(1)/m, Z = 4.