Solid-State Structure of Tp‘PtMe₂H, a Dimethylhydrido Platinum(IV) Complex

Abstract

The solid-state X-ray structure of Tp‘PtMe2H has been determined. This platinum(IV) hydride derivative is stable at room temperature and crystallizes in an orthorhombic cell (space group P cmn , Z = 4, a = 8.1292(8) Å, b = 13.3862(9) Å, and c = 17.9670(16) Å). The hydride ligand was not located. The complex was synthesized as one of a series of organometallic platinum(IV) derivatives with Tp‘ (Tp‘ = hydridotris(3,5-dimethylpyrazolyl)borate) in the coordination sphere. These octahedral platinum(IV) Tp‘PtMe2X and Tp‘PtPh2X complexes were prepared by formal oxidation of platinum(II) intermediates ([K][Tp‘PtMe2] and [K][Tp‘PtPh2]) with electrophiles (HX, MeI, I2). Thermogravimetric analysis (TGA) was employed to determine the solid-state decomposition temperatures for these platinum(IV) organometallic complexes.

Diacetylplatinum(II) and ‐platinum(IV) Complexes Bearing κ2‐ and κ3‐Coordinated Tris(pyrazolyl)methane Ligands: Investigations on the Synthesis, Fluxionality, and Reactivity in Relation to the Substitution Pattern of the Ligands

“…The 1 H NMR spectra of the hydridoplatinum(IV) complexes 3 and 5 exhibit the characteristic, far-upfield-shifted (δ = -17.98 to -18.73 ppm) hydride resonances with 1 J Pt,H coupling constants between 1619.7 and 1659.2 Hz as found for other hydridoplatinum(IV) complexes too. [18,20] In 1 H NMR spectra of 5a/b recorded in CD 3 OD no signal for the hydrido ligand was observed. However, the resonances and intensities of the other protons did not change significantly, which suggests an H-D exchange between the hydrido ligands and the solvent.…”

Hydrocarbon C—H Bond Activation with Tp'Pt Complexes

“…Alkane elimination in such systems has been proposed to occur through a five-coordinate intermediate generated by loss of a labile ligand. Stabilization of the octahedral geometry favored for the platinum(IV) d 6 configuration through the use of strong electron donating, fac- Figure 1: Structure ofhydridotHs (3,5-dimethylpyrazolyl) (29), with weak acids, including ammonium chloride and acetic acid, to give Tp'PtMe 2 H (1) (30) and TpPtMe 2 H (2) (31), respectively (eq 1). Protonation of the anionic Pt(II) precusor [K][Tp'PtMe 2 ] was shown to occur exclusively at metal to form the dimethylhydrido complex 1 suggesting a greater basicity at platinum than at either a pyrazole nitrogen or a platinum-hydrocarbon bond (30).…”

“…Stabilization of the octahedral geometry favored for the platinum(IV) d 6 configuration through the use of strong electron donating, fac- Figure 1: Structure ofhydridotHs (3,5-dimethylpyrazolyl) (29), with weak acids, including ammonium chloride and acetic acid, to give Tp'PtMe 2 H (1) (30) and TpPtMe 2 H (2) (31), respectively (eq 1). Protonation of the anionic Pt(II) precusor [K][Tp'PtMe 2 ] was shown to occur exclusively at metal to form the dimethylhydrido complex 1 suggesting a greater basicity at platinum than at either a pyrazole nitrogen or a platinum-hydrocarbon bond (30). Further support for the thermodynamic basicity of the Pt(II) center comes from the reaction of c&-PtMe 2 (SMe 2 )2 with the N-protonated Tp 1 ligand (ΗΤρ') to give complex 1 instead of the platinum(II) product [(HTp')PtMe 2 ].…”

“…Downloaded by IMPERIAL COLLEGE LONDON on February 18, 2015 | http://pubs.acs.org Publication Date: July 12, 2004 | doi: 10.1021/bk-2004-0885.ch018 In Activation and Functionalization of C-H Bonds; Goldberg, K., et al; ACS Symposium Series; American Chemical Society: Washington, DC, 2004.tridentate pyrazolylborate (29) ligands(Figure 1) allowed the isolation of stable alkyl(hydrido)platinum(IV) complexes(30,31).These platinum(IV) complexes can be synthesized by protonation of the anionic intermediates,[K][Tp ! PtMe 2 ] and [K][TpPtMe 2 ] [Τρ' = hydridotris(3,5-dimethylpyrazolyl)borate and Tp = tris(pyrazolyl)borate]…”

Syntheses of bispyrazolyl monotriazolyl heteroscorpionate platinum(IV) complexes including an unusual Pt-CH2CH2-Pt bridge

“…The 1 H NMR spectrum of the hydride product displayed two isomers in a 2:3 ratio with the symmetric complex as the major isomer. The major isomer has the hydride trans to the triazole arm and displays 1 J Pt-H = 1424 Hz, while the minor asymmetric isomer has 1 J Pt-H = 1480 Hz.Both 1 J Pt-H values are typicalcoupling constants for Pt(IV) hydride complexes 37,48,49.…”