Alloyed Tetranuclear Metal Chains of Pd4−nPtn (n=0–3) Scaffolded by a New Linear Tetraphosphine Containing a PNP Bridge. Issue 35 (15th May 2019)

• Record Type: Journal Article
• Authors: Tanase, Tomoaki; Tanaka, Miho; Hamada, Mami; Morita, Yuka; Nakamae, Kanako; Ura, Yasuyuki; Nakajima, Takayuki
• Is Part Of: Chemistry. Volume 25:Issue 35(2019)
• Page Start: 8219
• Page End: 8224
• Publication Date: 2019-05-15
• Subjects: alloyed metal chain -- EMAC -- PdPt mixed metal complex -- PNP bridged tetraphosphine -- tetranuclear complexes; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201901701
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: A new linear tetraphosphine containing a PNP phosphazane bridge, rac ‐bis[(diphenylphosphinomethyl)phenylphosphino]phenylamine ( rac ‐dpmppan), was synthesized and utilized to support a series of Pd/Pt mixed metal tetranuclear chains, [Pd4− n Ptn (μ‐ rac ‐dpmppan)2 (XylNC)2 ](PF6 )2 (XylNC=xylyl isocyanide; n =0: Pd4 (1 ), 1: PtPd3 (2 ), 2: PtPd2 Pt (3 ), 2: Pt2 Pd2 (4 ), 3: Pt2 PdPt (5 )), in which the number and positions of additional Pt atoms were successfully controlled depending on the respective synthetic procedures using transformations from 1 to 3 through 2 and from 4 to 5 by redox‐coupled exchange reactions. The 31 P{ 1 H} NMR and ESI mass spectra and X‐ray diffraction analyses revealed almost identical tetranuclear structures, with slight contraction of metal‐metal bonds according to incorporation of Pt atoms. The electronic absorption spectra of 1 –5 exhibited characteristic bands at 635–510 nm with an energy propensity depending on the number and positions of Pt centres, which were assigned to HOMO (dσ*σσ*) to LUMO (dσ*σ*σ*) transition by theoretical calculations. The present results demonstrated that the electronic structures of Pd/Pt mixed‐metal tetranuclear complexes are finely tuned as orbital‐overlapping alloyed metal chains by atomically precise Pt incorporation in the Pd4 chain. Abstract : Chain gang : A new linearly ordered tetraphosphine containing a PN(Ph)P phosphazane bridge, rac ‐bis[(diphenylphosphinomethyl)phenylphosphino]phenylamine ( rac ‐dpmppan), was synthesized and utilized to scaffold a series of Pd4− n Pt n mixed‐metal linear complexes including Pd4, PtPd3, PtPd2 Pt, Pt2 Pd2, and Pt2 PdPt chains, which are recognized as unprecedented alloyed metal atom chains.