Pt(PEt₃)(κ²-P,C-PEt₂CHMe)(C₆Cl₅): An Unexpected Intermediate in the Synthesis ofcis-Pt(PEt₃)₂(Cl)(C₆Cl₅)

Abstract

Addition of 1 to 6 equiv of LiC6Cl5 to cis-Pt(PEt3)2Cl2 gives the unexpected phosphine ligand C−H bond activation product Pt(PEt3)(κ2-P,C-PEt2CHMe)(C6Cl5) (1). Aqueous HCl addition to 1 gives the previously reported product of the reaction, cis-Pt(PEt3)2(Cl)(C6Cl5) (2).

Spontaneous Si–C bond cleavage in (TriphosSi)-nickel complexes

“…The high reactivity of L 4 M(CH 2 PMe 2 ) complexes (M = Co, Fe) and other phosphino methanide complexes 3,6,7,13,15,25,[31][32][33][34][35] prompted us to investigate the reactivity of the unprecedented complex 5. Most notable is the W(PMe 3 ) 3 (η 2 -CH 2 PMe 2 )H complex, which was reported as an electron-rich and highly reactive complex for the hydrodesulfurization of thiophenes.…”

“…[3][4][5] Likewise, the deprotonation of methylene-bridged bis-phosphines, the oxidative addition of R 2 PCH 3 or its deprotonated congener R 2 PCH 2 Li to metals was reported to afford phosphino methanide (R 2 PCH 2 ) complexes. 6,7 Moreover, Caulton and coworkers reported a transannular Si-C(sp 3 ) coordination in [(PNP)]NiCl (PNP = ( t Bu 2 PCH 2 SiMe 2 ) 2 N) 8 and selective bond cleavage leading to a phosphino methanide fragment coordinated to nickel. The R 2 PCH 2 unit was suggested to possess different mesomeric structures (Fig.…”

C–H Activation of Pyrazolyl Ligands by Ru(II)

“…Transition-metal mediated C–H activation has been heavily studied for several decades, and recent advances include many examples of transition-metal catalyzed C–H functionalization. − An important consideration for the design of catalysts for C–H functionalization is the possibility of intramolecular C–H activation of ligands that can compete with desired C–H activation of substrates. For example, phosphine ligands are often susceptible to cyclometalation. − Bidentate 2,2′-bipyridines have been reported to undergo “rollover” cyclometalation including reactions of Ir­(III), Rh­(III), Pd­(II), Pt­(II), and Au­(II) complexes. − The rollover cyclometalation occurs via rotation of the C–C bond to allow activation of the C(3)–H bond. Poly­(pyrazolyl)­alkane and poly­(pyrazolyl)­borate ligands with ≥ three pyrazolyl rings often coordinate to metals in a κ 3 - N , N , N mode; however, examples of intramolecular C–H activation at the 5-position of the pyrazolyl ring have been reported. − …”