We report the first observation of surface-enhanced Raman scattering (SERS) excited with ultraviolet (UV) light from transition metal electrodes. Adsorbed pyridine and SCN- on rough rhodium (Rh) ruthenium (Ru) electrodes, respectively, have been studied using 325 nm laser excitation. In contrast, best enhancers in visible near infrared, silver gold, do not produce UV-SERS. The experimental data UV-SERS are agreement our preliminary theoretical calculation based electromagnetic enhancement...

Density functional theory calculations were done to examine the potential energy surfaces of Ni(I)-catalyzed Negishi alkyl-alkyl cross-coupling reactions by using propyl iodide and isopropyl as model alkyl electrophiles CH 3ZnI a nucleophile. A four-step catalytic cycle involving iodine transfer, radical addition, reductive elimination, transmetalation steps characterized structurally energetically. The reaction mechanism for this appears feasible based on calculated free profiles reactions....

This discussion focuses on our recent approaches at aiming to optimize surface-enhanced Raman scattering (SERS) activity for transition metals (group VIII B elements), by intentionally fabricating desired surface nanostructures or synthesizing nanoparticles. The SERS of critically depends the morphology electrodes and size, shape aggregation form A correct roughening procedure transition-metal is indispensable cauliflower-like that show a higher activity. Two more methods have been explored...

The potential-energy surfaces of the reactions dirhodium tetracarboxylate (Rh2(II,II)) catalyzed nitrene (NR) insertion into C-H bonds were examined by a DFT computational study. A pure Becke exchange functional (B88) rather than hybrid (B3, BHandH) was found to be appropriate for calculation energy difference between singlet and triplet Rh2(II,II)-NH species. Rh2(II,II)-NR1 (R1 = (S)-2-methyl-1-butylformyl) is thermodynamically more favorable with free lower that Rh2(II,II)-N(PhI)R1. states...

Two mechanisms, namely, the Ni(0)–Ni(II) and Ni(I)–Ni(III) for nickel-bis(oxazolinyl)pyridine complex catalyzed Negishi cross-coupling reaction were investigated with density functional calculations. The mechanism, containing sequential steps of transmetalation–oxidative addition–reductive elimination, is more favorable than based on energetic span model. enantioselectivity coupled product from a racemic secondary alkyl electrophile was calculated by relative rate (rS/rR) reductive...

<title>Abstract</title> Dibenzyltoluene (DBT) is one of the most promising hydrogen storage media liquid organic carriers (LOHCs), but it difficult to solve problems low catalyst selectivity and deactivation caused by high by-products dehydrogenation. This study designed Pt_2.0Cu_0.1/Al₂O₃-900 ℃ that could balance activity, stability dehydrogenation perhydrodibenzyltoluene (18H-DBT). method involved appropriate acid pretreatment Pt-Cu synergistic...

Alumina support Pt catalyst with highly dispersed Cu shows synergistic effect for dehydrogenation of 12H-MBT.

Reported herein is an unprecedented copper-catalyzed site-selective δ-C(sp3)–H bonds activation of aliphatic sulfonamides for constructing the synthetically useful seven-membered N-heterocycles. A key to success use in-situ-formed amide radicals, activate inert C(sp3)–H bond, and inexpensive TMSNCO, as a coupling reagent under mild conditions. To best our knowledge, this represents first alkylamine derivatives five-membered synthon prepare

Sequential two-layer catalysts were used for the hydrogenolysis of glycerol to remove its oxygen content in a continuous-flow fixed-bed reactor. The acidic H-β catalyst layer was packed before Ni/Al2O3 sequential can provide good 1-propanol (1-PO) selectivities at high conversions (up 69% selectivity ∼100% conversion). To our knowledge, catalytic system this work presented one best 1-PO using non-noble metal based systems. A preliminary mechanistic study indicated that most products...

Abstract 1,8‐Diazabicyclo[5.4.0]undec‐7‐ene (DBU)/imine, DBU/imide DESs were designed and synthesized as CO 2 trapping agents. Toward this end, the optimal absorption temperature maximum capacity determined. It was found that ionicity is a key factor to affect of . Combined with calculation, new capture mechanism has been proposed. HBD in DES can be divided into two parts. One undergo proton transfer, obeying anion 2:1 absorption, whereas other, without amine 1:1 absorption. The degree...

The purpose of this paper is to report an efficient templating synthesis hierarchically porous SAPO-11 molecular sieves. Poly(vinyl alcohol) was phosphorylated get different phosphorus contents, and those designedly modified polymers were employed as mesoporous template in the hydrothermal SAPO-11. Consequently, prepared hierarchical sieves exhibited higher BET areas, regular mesopore structures, better acidity than their conventional counterpart. catalysts with SAPO-11s support had improved...

The reaction mechanism of the ruthenium−porhyrin complex [Ru(por)(CO)]-catalyzed intramolecular C−H bond amidation was examined using density functional theory (DFT) calculations. metal−nitrene reactive intermediate, Ru(por)(CO)−NSO3R1 (R1 = 1-methylclohexl-methyl) found to be highly favorable generate in terms free energy profile from starting materials. may exist both singlet and triplet states since they are close energy. In each state, six pathways were characterized structurally...

Understanding the reaction mechanism for oxidative dehydrogenation (ODH) of alkanes, especially key intermediate(s) that generates alkene is essential designing good ODH catalysts. To unravel mechanisms Ni-based oxide-catalyzed reactions, we investigated reactions C2H6 with Ni3Ox (x = 1, 2, 3) clusters by density functional calculations. For Ni3O3, three pathways were examined C–H bond activation step, and one concerted undergoing at two sites most favorable pathway, producing an ethylnickel...

A method to produce a substrate suitable for surface-enhanced Raman study on the pure massive Rh electrode was developed. The scattering (SERS) active with good stability, reversibility, and ease of preparation can be obtained by control-current electrochemical roughening method. surface enhancement factor estimated 3 orders magnitude. Such kind allows investigation not only some molecules large cross-section (e.g., pyridine) but also other very small (like CO). This result shows that used...

Some points on how to improve the detection sensitivity of confocal Raman microscopy for study surface-enhanced scattering (SERS) transition-metal electrodes are discussed, including careful design spectroelectrochemical cell, proper selection thickness solution layer, binning charge-coupled device (CCD) pixels, and appropriate setting notch filter. Various roughening methods Pt, Rh, Fe, Co, Ni electrode surfaces have been introduced in order obtain SERS-active surfaces. It has shown that...

The dehydration mechanisms for glucose in β-pyranose (BP) and open-chain (OC) forms, catalyzed by acids homogeneously heterogeneously, were investigated using density functional two-layer ONIOM calculations. first reaction competing pathways are the main focus of present study. energetics five two isomerization examined protonated form BP acidic aqueous solutions most favorable pathway these was found to be at anomeric site. No OC is favored over its or fructose. relative ease depends on...

A vapour deposition (VD) method was established for preparation of the UiO-66-supported Fe (Fe/UiO-66) catalyst, which provided first case metal-organic framework (MOF)-supported catalyst prepared by using vapour-based method. The loading around 7.0–8.5 wt% under present conditions. crystal structure UiO-66 not obviously influenced loading, while surface area significantly decreased, implicating most components resided in pores on UiO-66. results methyl orange (MO) removal tests showed that...