We provide the first observation and characterization of super electrophilic metal cations on a solid support. For Pd/SSZ-13, the results of our combined experimental (Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, high-angle annular dark-field scanning transmission electron microscopy) and density functional theory study reveal that Pd ions in zeolites, previously identified as Pd+3 and Pd+4, are, in fact, present as super electrophilic Pd+2 species (charge-transfer complex/ion pair with the negatively charged framework oxygens). In this contribution, we reassign the spectroscopic signatures of these species, discuss the unusual coordination environment of “naked” (ligand-free) super electrophilic Pd+2 in SSZ-13, and their complexes with CO and NO. With CO, nonclassical, highly positive [Pd­(CO)2]2+ ions are formed with the zeolite framework acting as a weakly coordinating anion (ion pairs). Nonclassical carbonyl complexes also form with Pt+2 and Ag+ in SSZ-13. The Pd+2(CO)2 complex is remarkably stable in zeolite cages even in the presence of water. Dicarbonyl and nitrosyl Pd+2 complexes, in turn, serve as precursors to the synthesis of previously inaccessible Pd+2–carbonyl–olefin [Pd­(CO)­(C2H4)] and Pd+2–nitrosyl–olefin [Pd­(NO)­(C2H4)] complexes. Overall, we show that the zeolite framework can stabilize super electrophilic metal (Pd) cations and show the new chemistry of the Pd/SSZ-13 system with implications for adsorption and catalysis.

The majority of harmful atmospheric CO and NO x emissions are from vehicle exhausts.A lthough there has been success addressing NO x emissions at temperatures above 250 8 8Cw ith selective catalytic reduction technology,e missions during vehicle cold start (when the temperature is below 150 8 8C), are am ajor challenge.H erein, we showw ec an completely eliminate both CO and NO x emissions simultaneously under realistic exhaust flow, using ah ighly loaded (2 wt %) atomically dispersed palladium in the extra-framework positions of the small-pore chabazite material as aC O and passive NO x adsorber.U ntil now,a tomically dispersed highly loaded (> 0.3 wt %) transition-metal/SSZ-13 materials have not been known. We devised ag eneral, simple,a nd scalable route to prepare such materials for Pt II and Pd II . Through spectroscopyand materials testing we showthat both CO and NO x can be simultaneously completely abated with 100 %e fficiency by the formation of mixed carbonyl-nitrosyl palladium complex in chabazite micropore.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

The majority of harmful atmospheric CO and NOx emissions are from vehicle exhausts. Although there has been success addressing NOx emissions at temperatures above 250 °C with selective catalytic reduction technology, emissions during vehicle cold start (when the temperature is below 150 °C), are a major challenge. Herein, we show we can completely eliminate both CO and NOx emissions simultaneously under realistic exhaust flow, using a highly loaded (2 wt %) atomically dispersed palladium in the extra‐framework positions of the small‐pore chabazite material as a CO and passive NOx adsorber. Until now, atomically dispersed highly loaded (>0.3 wt %) transition‐metal/SSZ‐13 materials have not been known. We devised a general, simple, and scalable route to prepare such materials for PtII and PdII. Through spectroscopy and materials testing we show that both CO and NOx can be simultaneously completely abated with 100 % efficiency by the formation of mixed carbonyl‐nitrosyl palladium complex in chabazite micropore.

<p>We provide the first observation and characterization of super-electrophilic metal cations on a solid support. For Pd/SSZ-13 the results of our combined experimental (FTIR, XPS, HAADF-STEM) and density functional theory study reveal that Pd ions in zeolites, previously identified as Pd⁺³ and Pd⁺⁴, are in fact present as super electrophilic Pd⁺² species (charge-transfer complex/ion pair with the negatively charged framework oxygens). In this contribution we re-assign the spectroscopic signatures of these species, discuss the unusual coordination environment of “naked” (ligand-free) super-electrophilic Pd⁺² in SSZ-13, and their complexes with CO and NO. With CO, non-classical, highly positive [Pd(CO)₂]²⁺ ions are formed with the zeolite framework acting as a weakly coordinating anion (ion pairs). Non-classical carbonyl complexes also form with Pt⁺² and Ag⁺ in SSZ-13. The Pd⁺²(CO)₂ complex is remarkably stable in zeolite cages even in the presence of water. Dicarbonyl and nitrosyl Pd⁺² complexes, in turn, serve as precursors to the synthesis of previously inaccessible Pd⁺²-carbonyl-olefin [Pd(CO)(C₂H₄)] and -nitrosyl-olefin [Pd(NO)(C₂H₄)] complexes. Overall, we show that zeolite framework can stabilize super electrophilic metal (Pd) cations, and show the new chemistry of Pd/SSZ-13 system with implications for adsorption and catalysis.<br></p>

Carbon moieties on late transition metals are regarded as poisoning agents in heterogeneous catalysis. Recent studies show the promoting catalytic role of subsurface C atoms in Pd surfaces and their existence in Ni and Pt surfaces. Here energetic and kinetic evidence obtained by accurate simulations on surface and nanoparticle models shows that such subsurface C species are a general issue to consider even in coinage noble‐metal systems. Subsurface C is the most stable situation in densely packed (111) surfaces of Cu and Ag, with sinking barriers low enough to be overcome at catalytic working temperatures. Low‐coordinated sites at nanoparticle edges and corners further stabilize them, even in Au, with negligible subsurface sinking barriers. The malleability of low‐coordinated sites is key in the subsurface C accommodation. The incorporation of C species decreases the electron density of the surrounding metal atoms, thus affecting their chemical and catalytic activity.

Interaction between CB[n] (n = 5–8) and biologically essential mono- and divalent metal cation.

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The results of our combined experimental (FTIR, XPS, HAADF-STEM, EXAFS) and density functional theory study reveals that Pd ions in zeolites, previously identified as Pd +3 and Pd +4 , are in fact present as super electrophilic Pd +2 species (ion pairs with the negatively charged framework oxygens). In this contribution we re-assign the spectroscopic signatures of these species, discuss the unusual coordination environment of "naked" (ligandfree) Pd +2 in SSZ-13, and their complexes with CO and NO. With CO, non-classical, highly positive [Pd(CO)2] 2+ ions are formed with the zeolite framework acting as a weakly coordinating anion (ion pairs). Non-classical carbonyl complexes also form with Pt +2 and Ag + in SSZ-13. The Pd +2 (CO)2 complex is remarkably stable in zeolite cages even in the presence of water. Dicarbonyl and nitrosyl Pd +2 complexes, in turn, serve as precursors to the synthesis of previously inaccessible Pd +2 -carbonyl-olefin [Pd(CO)(C2H4)] and -nitrosyl-olefin [Pd(NO)(C2H4)] complexes. Overall, we provide novel insight into the interactions of divalent metals with the zeolite framework, and show the new chemistry of Pd/SSZ-13 system with implications for adsorption and catalysis.