Synthesis and Reactivity of Heterotrinuclear Platinum Cyclometalated Complexes Containing Bridging Nitrido Ligands

• Published in: ChemistrySelect (Weinheim) 2020-07, Vol.5 (28), p.8691-8695
• Main Authors: Qin, Shiwei, Chong, Man‐Chun, Cheung, Wai‐Man, H.‐Y. Sung, Herman, Williams, Ian D., Leung, Wa‐Hung
• Format: Article
• Language: English
• Subjects: Cyclometalated; Heterometallic; Nitrido; Platinum complexes
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.202002319

The treatment of [M(LOEt)(N)Cl2] (LOEt−=[Co(η5‐C5H5){P(O)(OEt)2}3]−) with the Pt(II) bis(cyclometalated) complex [Pt(C N CBu)(DMSO)] (H2C N CBu=2,6‐di(4‐tert‐butylphenyl)pyridine; DMSO=dimethylsulfoxide) afforded the heterotrinuclear nitrido complexes [LOEtCl2M(μ‐N)Pt(C N CBu)] (M=Ru (1‐Ru), Os (1‐Os)). The Pt−N(nitrido) (1.821(5) Å) and Ru−N (1.673(5) Å) distances in 1‐Ru are consistent with the Ru=N=Pt bonding description. The Pt−N(nitrido) distance in 1‐Os (1.859(7) Å) is longer than that in 1‐Ru, suggesting the π interaction between Pt(II) and Os≡N is weaker than that for the Ru counterpart. Oxidation of 1‐Ru with PhICl2 afforded the Pt(IV) dichloride complex [LOEtCl2Ru(μ‐N)Pt(C N CBu)Cl2] (2) that has a longer Pt−N distance (1.893(3) Å) than that in 1‐Ru, indicating the weakening of the Pt−N(Ru) π bonding upon oxidation of Pt(II) to Pt(IV). Treatment of [Pt(C N CBu)(DMSO)] with [nBu4N][Ru(N)Cl4] in tetrahydrofuran (THF) afforded [nBu4N][(THF)Cl4Ru(μ‐N)Pt(C N CBu)] (3), which reacted with K[N(Ph2PS)2] and K[N(iPr2PO)2] to yield [Cl{N(Ph2PS)2}2Ru(μ‐N)Pt(C N CBu)] (4) and [nBu4N][Cl3{N(iPr2PO)2}Ru(μ‐N)Pt(C N CBu)] (5), respectively. The short Pt−N(nitrido) distances in 3 (1.816(5) Å) and 4 (1.809(2) Å) are indicative of Pt=N double bond character. Heterometallic Pt nitrido complexes have been synthesized from reactions of a cyclometalated Pt(II) complex with M(VI) (M=Ru, Os) terminal nitrides. Oxidation of the Pt(II)‐N−Ru(VI) complexes with PhICl2 gives Pt(IV)‐N−Ru(VI) complexes. The Pt−N π bonding in the Pt‐N−M complexes is found to be dependent on the Pt oxidation state and the nature of M.