No abstract

A canary yellow block with dimensions 0.261 x 0.167 x 0.154mm 3 was placed and optically centered on the Bruker SMART CCD system at -80°C. The initial unit cell was indexed using a least-squares analysis of a random set of reflections collected from three series of 0.3° wide ω scans (25 frames/series) that were well distributed in reciprocal space. Data frames were collected [MoKα] with 0.3° wide ω-scans, 40 seconds per frame, 606 frames per series. Five complete series were collected with an additional 160 frames a repeat of the first series for redundancy and decay purposes, with a crystal to detector distance of 4.556cm, thus providing a complete sphere of data to 2θ max =50°. A total of 38144 reflections were collected and corrected for Lorentz and polarization effects and absorption using Blessing's method as incorporated into the program SADABS 1,2 with 10464 unique [R(int)=0.0693]. Structural determination and Refinement:All crystallographic calculations were performed on a Personal computer (PC) with dual Pentium 450MHz processors and 384MB of extended memory. The SHELXTL 3 program package was now implemented, XPREP, to determine the probable space group and set up the initial files. System symmetry, lack systematic absences and intensity statistics indicated the centrosymmetric triclinic group P-1 (no.2). The structure was determined by use of Patterson methods with the successful location of the central Zirconium atom using the program XS 4 . The structure was refined with XL 5 . After the initial refinement difference-Fourier cycle, additional atoms were located and input. After several of these refinement difference-Fourier cycles, all of the atoms were refined isotropically, then anisotropically. A disordered chlorobenzene molecule was modeled and refined with three probable orientations. A centroid was calculated for the pentamethylcyclopentadienyl group. Hydrogen atoms were placed in calculated positions. The final structure was refined to convergence [∆/σ ≤ 0.001] with R(F)=8.87%, wR(F 2 )=11.43%, GOF=1.009 for all 10464 unique reflections [R(F)=4.51%, wR(F 2 )=10.21% for those 6868 data with Fo > 4σ(Fo)]. A final difference-Fourier map was featureless indicating the structure is therefore both correct and complete.The function minimized during the full-matrix least-squares refinement was Σw(Fo 2-Fc 2 ) where w=1/[σ 2 (Fo 2 )+(0.0590*P) 2 +0.0*P] and P=(max(Fo 2 ,0)+2*Fc 2 )/3. An empirical correction for extinction was also attempted but found to be negative and therefore not applied.53.78(11) N(1)-Zr(1)-C( 16) 30.17(11) CT1-Zr(1)-C( 16) 122.21( 9) O(1)-Zr(1)-C( 16) 107.16(10) C(11)-Zr(1)-C(16) 107.43(13) N(2)-Zr(1)-C(16) 29.95(10) C(5)-Zr(1)-C(16) 97.80(10) C(1)-Zr(1)-C(16) 98.40(11) C(3)-Zr(1)-C(16) 150.75(11) C(4)-Zr(1)-C(16) 125.78(11) C(2)-Zr(1)-C(16) 126.86(12) C(2)-C(1)-C(5) 107.6(3) C(2)-C(1)-C(6) 126.2(4) C(5)-C(1)-C(6) 125.9(4) C(2)-C(1)-Zr(1) 74.4(2) C(5)-C(1)-Zr(1) 73.07(19) C(6)-C(1)-Zr(1) 123.1(2) C(1)-C(2)-C(3) 108.7(3) C(1)-C(2)-C(7) 126.4(4) C(3)-C(2)-C(7) 124.3(4) C(1)-C(2)-Zr(...

No abstract

No abstract

Herein we report our efforts to prepare new precursors to niobium nitride (NbN) and tantalum nitride (TAN, Ta3N5) thin films. Treatment of MC15 (M = Nb, Ta) with tertbutylamine in benzene solvent affords complexes of the formula [MCI2 (NtBu)(NHtBu)(NH2tBu)]2. The niobium complex [NbC12(NtBu)(NHtBu)- (NH2tBu)]2 affords NbN films on glass substrates between 500-600 °C, while the tantalum analog [TaC12(NtBu)(NHtBu)(NH2tBu)]2 gives films of Ta3N5 in this temperature range. Treatment of MCI5 (M = Nb, Ta) with 1,1-dimethylhydrazine in dichloromethane solvent affords complexes of the formula [MC12(NNMe2)(NHNMe2)(NH2NMe2)]n. These hydrazido complexes afford cubic MN films upon glass substrates at ≥400°C. Analyses of the films are presented.