Methyl[hydrotris(1-pyrazolyl)borato]tetrafluoroethyleneplatinum

Abstract

Abstract.(CH3)[HB (CsH3N2)3] (C 2Fa)Pt, CI2HI3-BF4N6Pt , M r -523.2, orthorhombic, P212121 (No. 19),a = 12.993 (2), b = 9.156 (1),c= 13.372 (2)A, V = 1590.8 A 3, Z = 4, g = 173.7 cm -~, D x = 2.18, D m = 2.14 (1) g cm -3. Full-matrix least-squares refinement of 1801 reflections yielded a final R of 0.037. The structure consists of a trigonal-bipyramidal arrangement of the three pyrazolyl N atoms, the methyl group and the C2F 4 ligand about the Pt atom. Short intramolecular contacts involving one methyl H atom and two of the F atoms of the C 2F4 ligand are observed.Introduction. Suitable crystals of the title compound, MTFPT, were obtained by slow evaporation of a hexane solution. All X-ray measurements were made using a Diano XRD-700 diffractometer equipped with a single-crystal orienter with Cu K¢~ radiation and at ambient room temperature (~22°C). Least-squares refinement of 37 independent reflections with K¢~ (1.54051 A) and Kct 2 (1.54433 A) well resolved yielded the unit-cell dimensions. The data crystal was bounded by {011}, 0.17 mm apart; {001}, 0.18 mm apart; {0i 1 }, 0.21 mm apart and was cut perpendicular to these faces to a height of 0.36 mm. The crystal was mounted with [100] parallel to the ¢p axis of the goniostat. Intensity-weighted plots of the reciprocal lattice were used to determine the space group. Measurements of 09 scans along the principal axes indicated suitable quality for data collection by the stationary-crystal/stationary-counter technique using a balanced Ni-Co filter pair. A total of 1826 unique reflections accessible within the range 3 ° < 20 < 145 ° were measured.Analysis of the intensities of the six check reflections indicated a 6% isotropic decay during the 5 d of data collection. The data were broken into five blocks of approximately equal size and the appropriate decay factors were applied. Additional corrections to the net intensities were applied to account for Lorentz and polarization effects, tt ~-~t2 splitting (Tulinsky, Worthington & Pignataro, 1959) and absorption as a function of crystal shape (J. M. Williams, Argonne National Laboratory program MET 176X). Standard deviations in the structure factor amplitudes, o(IFol),

A brief history of scorpionates

“…The first crystal structure incorporating a Tp ligand was reported in 1970, namely bis[hydrotris(pyrazol-1-yl)borato]cobalt(II), which confirmed the D3d symmetric structure for bis-Tp complexes (Churchill et al, 1970) previously theorized based on comparative transition metal complex series colors and molecular modeling (Trofimenko, 1967). In 1978, the first Tp structure to appear in an Acta Crystallographica journal, methyl[hydrotris(pyrazol-1-yl)borato]tetrafluoroethyleneplatinum, afforded an accurate stereochemical description to elucidate previously observed anomalous couplings in the NMR spectra (Rice & Oliver, 1978). The perfluoroalkyne analogue had been reported four years previously (Davies & Payne, 1974).…”

“…The composite sepia background is from the packing diagram of a representative bis-Tp complex (Nakata et al, 1995). The top molecule was generated from atomic coordinates from the first scorpionate to appear in an Acta Crystallographica journal (Rice & Oliver, 1978). The lower molecule is one of the most recent scorpionates, that is to say, a molecule from this issue!…”