The reaction of (NEt4)2[MoNCl5] and K{HB(Me2pz)3}[HB(Me2pz)3- = tris (3,5- dimethylpyrazol-1-yl) hydroborate anion] produces both purple, diamagnetic {HB(Me2pz)3}MoNCl2 (1) and yellow, paramagnetic Net4 [{HB(Me2pz)3}MoNCl2] (2) (e.s.r.: {g} 1.961, {a}(95Mo) 57×10-4 cm-1), which have been separately isolated under different conditions. In contrast, the reaction of [ MoN (N3)4]- with Na{HB(Me2pz)3} results in the exclusive formation of red {HB(Me2pz)3} MoN (N3)2 (3). Crystals of (3) are monoclinic and belong to space group P21/n with a 16.440(2), b 8.787(2), c 16.754(2) Ǻ,β 112.47(1)°, V 2236.4 Ǻ3, and Z 4. The structure was solved by Patterson and Fourier methods, followed by least-squares refinement, using 3208 reflections, to a conventional R value of 0.032 ( Rw 0.047). In the distorted octahedral complex the molybdenum(VI) atom is coordinated by a facial HB(Me2pz)3- ligand , a terminal nitrido ligand with a Mo-N bond distance of 1.646(4)Ǻ, and two azide ligands. All complexes have been characterized by elemental analysis, infrared, 1H n.m.r. or e.s.r. spectroscopy, and mass spectrometry. Improved syntheses for the starting materials (NEt4)2 [MoNCl5] and (NEt4)2 [MoNCl4] are also reported.
Abstract.[Mo ( Experimental. The title compound, LMoO(OC6H4-C1)2, was synthesized and purified using procedures similar to that of previous literature (Cleland et al., 1987), and crystallized by slow evaporation from a saturated benzene solution at room temperature (3 weeks). A dark ruby-red pyramidal-shaped crystal of approximate dimensions 0.55 x 0.30 x 0.22 mm was mounted on a glass fiber with epoxy. The measurements were performed on an automated four-circle Syntex P21 diffractometer with graphite-monochromated Mo Ka radiation. No absorption correction was applied, to scans of several intense reflections were measured and the width at halfheight was 0.25 ° . Lattice parameters were obtained from the setting angles of 25 reflections in the range 20 < 20 < 30 °. No systematic absences were observed and the space group was determined to be P1. Data * Presented in part at the 200th ACS National Meeting, 26-31 August, 1990, Washington, DC, USA.I" Undergraduate participant from the Department of Biochemistry, Marlboro College, Marlboro, Vermont 05344, USA.Author to whom correspondence should be addressed.0108-2701/92/061096-02506.00were collected in 0-20 scan mode with 20max = 50°; (sin0max)/A = 0.595/~-I. The scan rate varied from 2 to 8 ° min -1 depending upon the intensity of the reflection. The data covered the index range 0 < h _< 13, -15_ 3tr(Fo 2) were used in refinement. The structure was solved using the Patterson method to locate the Mo atom, followed by successive difference Fourier syntheses. Full-matrix least squares, based on F's, using anisotropic thermal parameters, were used to refine all non-H atoms, H atoms were included at calculated positions, with fixed thermal parameters and numbering of the atoms in the pyrazole ring containing N11 and N21 parallels that shown for the ring containing N31.
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