Platinum complexes with diamino-substituted phosphorus ligands: Synthesis, characterization, and their reactivity with a Lewis acid

Abstract

Reaction of dialkyl-or diaryl-platinum complexes PtR 2 (cod) (cod = h 2 , h 2 -1,5-cyclooctadiene, R = Me, p-tol) with diamino-substituted phosphorus ligands P(NMeCH 2 ) 2 (R 0 ) (R 0 = OMe, NEt 2 ) produced neutral complexes, cis-[Pt(R) 2 {P(NMeCH 2 ) 2 (R 0 )} 2 ]. On the other hand, reaction of dihalogeno platinum complex PtX 2 (cod) (X = Cl, I) with P(NMe-CH 2 ) 2 (OMe) yielded a cationic complex [PtX{P(NMeCH 2 ) 2 (OMe)} 3 ]X. A platinum complex having both methyl and halogeno ligands, PtMeX(cod), reacted with P(NMeCH 2 ) 2 (OMe) to give a cationic methyl complex [PtMe{P(NMeCH 2 ) 2 (OMe)} 3 ]X, by contrast, it reacted with P(NMeCH 2 ) 2 (NEt 2 ) to yield a neutral methyl complex [PtMeX{P(NMeCH 2 ) 2 (NEt 2 )} 2 ]. Reaction of [PtMe{P(NMeCH 2 ) 2 (OMe)} 3 ]X with BF 3 ÁOEt 2 and then NaBPh 4 afforded [PtX{P(NMeCH 2 ) 2 (OMe)} 3 ]BPh 4 , showing preferential Me group abstraction on the Pt center rather than the OMe abstraction on the phosphorus atom, followed by the coordination of X to the Pt center. All new complexes were fully characterized using 1 H, 13 C{ 1 H}, and 31 P{ 1 H} NMR measurements and elemental analyses. In addition, structures of several complexes were determined by single crystal X-ray diffraction studies.

Synthesis, characterization, and crystal structure of cis‐[Pt(Me)2{PPh2(OMe)}2] and the conversion into cis‐[Pt(OH2)2{PPh2(OMe)}2][OTf]2

“…The 31 P{ 1 H} NMR spectrum of 1 showed a signal at δ 116.71 flanked by 195 Pt satellites ( 1 J (P–Pt) = 2204 Hz). These values are similar to those of the cis‐ dimethylplatinum complex with diamino‐substituted phosphorus ligands, cis‐ [Pt(Me) 2 {P(NMeCH 2 ) 2 (OMe)} 2 ] 9.…”

“…We believe that H 2 O molecules in 2 come from adventitious water in the solvent and/or HOTf. The tendency of methyl abstraction is similar to that of analogous cis‐ [Pt(Me) 2 {P(NMeCH 2 ) 2 (OMe)} 2 ] with BF 3 ·OEt 2 as a Lewis acid 9. The reaction in Eq.…”