1.03 e -k'). Data were collected on an Enraf-Nonius C A D 4 diffractometei-. and calculations were performed with the TEXSAN software package. X-ray crystal structure analysis of 4.0.5 toluene: green block crystal (0.50 x 0.50 x 0.25 mm): C,, ,,,H,,CuN,O,. M = 647.42. monoclinic. space group P2,'ii. 0=17.5316(4)!% h=9.3694(3),& ( = 22.1187(S)A. / I = 91.444(1), V=3632.1(2)A3. Z = 4 at 173(2) K: (I,,,,,, =I.lX4gcm-'.
20,,,,, = 50.18 : pMS = 6.36 cm-'. The structure was solved by direct methods:
non-hydrogen atoms were refined aiiisotropically. and hydrogen atoms were placed at calculated positions and refined as riding atoms with individual isotropic displacement parameters. A semiempirical absorption corrcctioii was applied. A disordered toluene molecule was located on a n inber$ion center: the occupancies of its atoms were fixed at 0.5 to account for the disorder. The final cycle of full-matrix least-quai-es refinement (on F'). based on 6402 reflections [I>2ri(/)] and 495 variable parameters. converged at R1 = 0.0359, and II R2 = 0.0865 (max min residual electron density 0.264 -0.369 e A -').
Data were collected on a Siemens SMART system and calculations were performed using the SHELXTL V5.0 suite of prograins Crystallographic data (excluding structure factors) for the sti-ucturcs reported in this paper have been deposited with the Cambridge Crystallographic Data Centre as supplementary publications no. CCDC-179.44. Copies of the data can be obtained free of charge on application to The Director. CCDC. 12 Union Road.
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