Since the first reports in the late 1970s on transition metal complexes contain- ing pincer-type ligands—named after the particular coordination mode of these ligands—these systems have at- tracted increasing interest owing to the unusual properties of the metal centers imparted by the pincer ligand. Typical- ly, such a ligand comprises an anionic aryl ring which is ortho,ortho-disubsti- tuted with heteroatom substituents, for example, CH2NR2 ,C H 2PR2 or CH2SR, which generally coordinate to the met- al center, and therefore support the MC s bond. This commonly results in a terdentate and meridional coordina- tion mode consisting of two metalla- cycles which share the MC bond. Detailed studies of the formation and the properties of a large variety of pincers containing platinum group metal complexes have provided direct access to both a fundamental under- standing of a variety of reactions in organometallic chemistry and to a range of new applications of these complexes. The discovery of alkane dehydrogenation catalysts, the mecha- nistic elucidation of fundamental transformations (for example, CC bond activation), the construction of the first metallodendrimers for sustain- able homogeneous catalysis, and the engineering of crystalline switches for materials processing represent only a few of the many highlights which have emanated from these numerous inves- tigations. This review discusses the synthetic methodologies that are cur- rently available for the preparation of platinum group metal complexes con- taining pincer ligands and especially emphasizes different applications that have been realized in materials science such as the development and engineer- ing of sensors, switches, and catalysts.

Platinum Group Organometallics Based on “Pincer” Complexes: Sensors, Switches, and Catalysts

The impact of agostic interactions (i.e., 3-center-2-electron M-H-C bonds) on the structures and reactivity of organotransition metal compounds is reviewed.

https://www.pnas.org/content/pnas/104/17/6908.full.pdf

Agostic interactions in transition metal compounds

Interactions between CH and NH bonds and d8 square planar metal complexes: hydrogen bonded or agostic?

The most attractive and fundamental interaction between metal centers and organic molecules that could lead to new functionalization at carbon is direct activation of the C-H bonds of hydrocarbons In particular, transition metal complexes have been used not only in pioneering studies of the synthesis or detection of complexes resulting from C-H activation, but also in cyclometalation chemistry In most of the reactions reviewed here intramolecular assistance by a nucleophile plays a major role in the mechanism and/or in the stabilization of products, and
thus they are relevant also to the development of a
better understanding of cyclometalation reactions This Account summarizes recent research that implicates the occurrence of electrophilic attack at the metal center in reactions leading to metal-electrophile bonding

/pdf/mechanisms-of-d8-organometallic-reactions-involving-5agz1x55d0.pdf

Mechanisms of d8 organometallic reactions involving electrophiles and intramolecular assistance by nucleophiles

Metallorganische Pinzetten-Komplexe von Elementen der Platingruppe: Sensoren, Schalter und Katalysatoren

Les deux composes du titre cristallisent dans le systeme monoclinique, groupe d'espace P2 1 /c et leur structure est affinee jusqu'a R=0,058 pour le complexe de palladium et jusqu'a R=0,045 pour le complexe de platine

Preparative and 1H NMR spectroscopic studies on palladium(II) and platinum(II) quinoline-8-carbaldehyde (1) complexes. X-ray structures of the cyclometalated acyl complex PdCl(C(O)C9H6N)(PPh3)•PPh3 and trans-PtCl2(1)(PEt3)

H. Ruegg

Papers

Preparative and 1H NMR spectroscopic studies on palladium(II) and platinum(II) quinoline-8-carbaldehyde (1) complexes. X-ray structures of the cyclometalated acyl complex PdCl(C(O)C9H6N)(PPh3)•PPh3 and trans-PtCl2(1)(PEt3)