Synthesis and structure of trihydride hexaplatinum complex supported by triphosphine ligands, [Pt6(μ-H)(H)2(μ-dpmp)4]BH4 (dpmp = bis(diphenylphosphino-methyl)phenylphosphine)

• A novel linear trihydride hexaplatinum complex was successfully synthesized.
• The HPt3HPt3H structure was characterized by X-ray diffraction and DFT methods.
• The Pt6H3 string is retained in solution confirmed by spectroscopic analyses.

From a reaction of [Pt3(μ-dpmp)2(XylNC)2](PF6)2 (1a) with NaBH4 and [Pt(dba)2] in N,N-dimethyl formamide (DMF), a trihydride hexaplatinum complex, [Pt6(μ-H)(H)2(μ-dpmp)4]BH4·DMF (4*·DMF), was isolated as dark green crystals in 47% yield, and was characterized by IR, UV–vis, 1H and 31P{1H} NMR, and ESI mass spectral analyses, X-ray crystallography, and DFT calculations. Complex 4* is stable in DMF and DMSO solutions, and contains two terminal and one bridging hydrides observed at −5.92 ppm (1JPtH = 980 Hz) and −4.47 ppm (1JPtH = 591 Hz) in the 1H NMR spectrum (DMSO-d6). The X-ray diffraction analysis revealed the linear hexaplatinum structure supported by four dpmp ligands, wherein two {Pt3(H)(μ-dpmp)2}+ units are connected by the bridging hydride resulting in a long Pt⋯Pt separation (3.3075(6) Å) between the central two Pt atoms. Other PtPt distances range from 2.7243(7) to 2.7499(6) Å, indicating the presence of PtPt bonds within the {Pt3(μ-dpmp)2} units. On the basis of the crystal structure, the hydride positions were optimized by DFT calculations to show a bent bridging hydride (av. PtH = 1.65 Å, PtHPt = 160.0°) as well as linear terminal ones (av. PtH = 1.68 Å, av. PtPtH = 179.4°). The present study provides useful information in expanding molecular metallic chains by utilizing {HPt3HPt3H}+ building blocks.

Trihydride hexaplatinum complex, [Pt6(μ-H)(H)2(μ-dpmp)4]BH4·DMF (4*·DMF), was synthesized and characterized by spectroscopic, crystallographic and theoretical methods to demonstrate a novel {HPt3HPt3H}+ core with two terminal and one bridging hydrides.Figure optionsDownload as PowerPoint slide