Monomeric Chini‐Type Triplatinum Clusters Featuring Dianionic and Radical‐Anionic π*‐Systems

Abstract

Owing to their unique topologies and abilities to self-assemble into a variety of extended and aggregated structures, the binary platinum carbonyl clusters [Pt3 (CO)6 ]n (2-) ("Chini clusters") continue to draw significant interest. Herein, we report the isolation and structural characterization of the trinuclear electron-transfer series [Pt3 (μ-CO)3 (CNAr(Dipp2) )3 ](n-) (n=0, 1, 2), which represents a unique set of monomeric Pt3 clusters supported by π-acidic ligands. Spectroscopic, computational, and synthetic investigations demonstrate that the highest-occupied molecular orbitals of the mono- and dianionic clusters consist of a combined π*-framework of the CO and CNAr(Dipp2) ligands, with negligible Pt character. Accordingly, this study provides precedent for an ensemble of carbonyl and isocyanide ligands to function in a redox non-innocent manner.

Geometric and Electronic Structure Analysis of the Three-Membered Electron-Transfer Series [(μ-CNR)2[CpCo]2]n (n = 0, 1–, 2−) and Its Relevance to the Classical Bridging-Carbonyl System

“…For example, treatment of diiodide 1 with 3.1 equiv of KC 8 provides the red-orange monopotassium salt, K­[(μ 2 -CNAr Mes2 ) 2 ­[CpCo] 2 ] (K­[ 2 ]), as determined by X-ray diffraction (Figure ). In the solid state, K­[ 2 ] is found as a tight ion pair, , with significant π-arene interactions between the CNAr Mes2 mesityl groups and the potassium cation. − The solution IR spectrum of K­[ 2 ] in C 6 D 6 features a prominent ν CN stretch centered at 1666 cm –1 , which reflects significant increase in Co→(CN)­π* back-donation relative to 2 . 1 H NMR analysis of K[2] in C 6 D 6 solution revealed broad, shifted resonances consistent with a paramagnetic complex.…”

Heterometallic Ni–Pt Chini-Type Carbonyl Clusters: An Example of Molecular Random Alloy Clusters

“… 4 − 7 , 39 − 42 Moreover, it has been demonstrated recently that Chini-type clusters can display new reactivity and electronic states upon ligand substitution. 43 They represent a continuous challenge, which we believe it worth of pursuing.…”

[Ni3(iPr2Im)3(µ2‐CO)3(µ3‐CO)] – A CO‐Stabilized NHC Analogue of the Parent Neutral Nickel Chini‐Type Cluster

“…Complex 2 is usually a side product in the synthesis of 1 , so that typically less than one equivalent of the NHC is used for the synthesis of 1 . Cluster complex 1 represents to the best of our knowledge the first neutral nickel species in the field of the Chini cluster complexes, though it is a heteroleptic compound comparable to Figueroa's platinum cluster [Pt 3 ( µ 2 ‐CO) 3 (CNAr) 3 ] . To evaluate the situation for the parent cluster complex [Ni 3 (CO) 3 (µ‐CO) 3 ] it is interesting to note that no neutral, trinuclear, nickel(0) carbonyl complex was isolated so far.…”