Synthesis and structure of new palladium complexes with the ligand 2-(diphenylphosphino)-1-methylimidazole: Evidence of hemilability

The development of phosphinoamine–Pd(II)–imidazole complexes: implications in room‐temperature Suzuki–Miyauracross‐coupling reaction

“…The IR spectrum in KBr shows a new band at 278 cm −1 , consistent with Pd–N imidazole vibration. Similar to complex 1 , all other bands are observed as expected . In the UV–visible spectrum, complex 2 also displays two bands at 270 nm and 228 nm for intra‐ligand π→π* and one at 342 nm with a blue shift for n→π* transitions .…”

“…Enhanced electron density at the metal center increases the degree of back‐donation from metal to PPh 2 Etpy ligand. The signal for 31 P nuclei of the PF 6 − ion was detected as a septet at δ = −160.85 ppm with J PF = 712 Hz . In the 1 H NMR spectrum two singlets at δ = 8.42 and 3.37 ppm with downfield shift are attributed to H 2′ and NCH 3 protons.…”

“…The enhanced back‐donation might cause an upfield shift of 0.83 ppm in 1 relative to the parent compound. The 31 P resonance of the PF 6 − counterion for complex 1 is observed at δ = −175.60 ppm with J PF = 712 Hz . The 1 H NMR spectrum of the complex exhibits a singlet at δ = 8.15 ppm due to the H 2′ (Scheme ) proton of N‐MeIm with 0.75 ppm downfield shift compared to free N‐MeIm, clearly indicating coordination of the imidazole through the N(3′) atom.…”

“…S1, supporting information) shows a singlet at δ = −9.76 ppm which was shifted upfield with respect to the neutral parent compound [PdCl 2 (PPh 2 py–P,N)] ( δ = −9.15 ppm). The PF 6 − ion resonance for complex 2 was observed at δ = −176.57 ppm with J PF = 712 Hz . The 1 H NMR spectrum of complex 2 , in addition to aromatic protons, shows a singlet at δ = 8.21 ppm for H 2′ of N‐BuIm (Scheme ), which is shifted downfield compared to free ligand.…”

Rhodium complexes of 1,3-diaryltriazenes: Usual coordination, N–H bond activation and, N–N and C–N bond cleavage

“…Examples of such g 1 -bound aryl complexes are relatively less common in the literature [58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73]. It may be added in this context that metal mediated C-N bond cleavage, though not very uncommon, is mostly limited to strained amines and amidines [74][75][76][77][78][79], and hence there is significant interest in transition metal mediated C-N bond cleavage [80][81][82][83][84][85][86][87][88][89].…”