Addition of Ammonia, Water, and Dihydrogen Across a Single Pd−Pd Bond

A terminal palladium fluoride complex supported by an anionic PNP pincer ligand

“…All diffractometer manipulations, including data collection, integration and scaling were carried out using the Bruker Apex2 software [28]. An absorption correction was applied using SADABS [29]. The space group was determined on the basis of systematic absences and intensity statistics and the structure was solved by direct methods and refined by full-matrix least squares on F 2 .…”

Ammonia Activation by a Nickel NCN‐Pincer Complex featuring a Non‐Innocent N‐Heterocyclic Carbene: Ammine and Amido Complexes in Equilibrium

“…5 Another significant development was the introduction of pincer complexes by Hartwig and later Turculet, who described the activation of ammonia on Ir I PCP and PSiP pincer complexes, respectively, to yield mononuclear, terminal L(H)Ir III -NH2 derivatives. 6 Also notable is the homolytic ammonia activation by a dinuclear Pd I PNP pincer complex, reported by Ozerov, where a terminal LPd II -NH2 species was obtained along with LPd II -H. 7 Ammonia activation via metathesis, without formally changing the oxidation state of the metal, is well documented on several metals including Ru and Ir I , 8 but can pose problems in terms of catalysis because the hydrogen is removed from the catalytic site. Milstein showed evidence for the heterolytic, deprotonative N-H bond activation of ammonia using a Ru II complex incorporating non-innocent PNP pincer ligands, without observing the corresponding LRu II -NH2 species.…”

Cooperative Catalysis with First‐Row Late Transition Metals

“…[67,68] Ozerov has described the formation of specific Pd I (PNP) dimers -PNP = bis[2-(diisopropyl-phosphanyl)-4-methylphenyl]amido -via photolytic activation of the corresponding mononuclear Pd(PNP)(alkyl) species and utilized these systems (Scheme 14), which feature an unsupported Pd-Pd single bond and can thus be viewed as two-electron reductants, for the bimetallic, homolytic activation of particular H-E bonds, most notably H 2 O and NH 3 . [69] It remains to be seen if similar strategies may be fruitful with first-row analogues, especially in combination with redoxactive ligands (vide infra). Peters has developed dinuclear copper species based on the same PNP ligand scaffold as well as its close structural PPP derivative [PPP = bis(2-diisopropylphosphanyl)phenylphosphane], [80] which showed very interesting electronic behaviour, allowing the isolation of mixed-valent states as well as spectacular, long-lived luminescence.…”