Reactions of Nbn+ (n = 2-6) with Ethylene in the Gas Phase: Collision-Induced Dissociation Studies of Ionic Products

Abstract

The gas-phase reactions of Nb,+ (n = 2-6) with C2& are studied by Fourier transform mass spectrometry. Collision-induced dissociation (CID) and ion-molecule reactions are used to probe the product ion structures.The sequential reactions of N b 2 + are believed to involve ligand coupling, while for the larger clusters this mechanism is less important. The bonding between the Nb atoms and the C atoms of the ligand in the product ions becomes stronger with increasing cluster size. One of the major product ions from the reaction of Nb4+ with ethylene, Nb4C4+, is especially stable and believed to be the distorted 2 x 2 x 2 cubic "nanocrystal" structure observed in supersonic expansions. The thermochemical limits, Do(Nb,+ -CZ) L 186.3 kcaYmol (n = 3-6), were derived on the basis of the observation of the complete dehydrogenation of ethylene.

Thresholds for the Collision-Induced Dissociation of Clusters by Rare Gas Impact

“…Parameters for the Morse function called Morse*1 were chosen so that Morse*1 gives the following: (1) an Ar + Al 6 (O h ) energy transfer probability distribution and CID cross section versus E rel in near exact agreement with those for the above L-J/A-T potential; (2) potential. Parameters for the Morse function called Morse*1 were chosen so that Morse*1 gives the following: (1) an Ar + Al 6 (O h ) energy transfer probability distribution and CID cross section versus E rel in near exact agreement with those for the above L-J/A-T potential; (2) potential.…”

“…Collision-induced dissociation (CID) of cationic clusters with rare gases have been used to study dissociation mechanisms 1 and bond energies for the clusters. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] The CID cross section is measured versus the cluster-rare gas relative translational energy, and the bond dissociation energy for the cluster has been estimated from the CID threshold E o CID .…”

“…Collision-induced dissociation (CID) of cationic clusters with rare gases have been used to study dissociation mechanisms and bond energies for the clusters. − The CID cross section is measured versus the cluster−rare gas relative translational energy, and the bond dissociation energy for the cluster has been estimated from the CID threshold . For to be the true threshold E o , there must be collisions which transfer all the relative translational energy to cluster internal energy …”

Reactions of Nbn+ (n = 1−15) with Propene and 1-Butene: Product Distribution as a Function of Cluster Size

“…A wide variety of reactions of different metal cluster ions has been reported in the literature . In particular, several studies have been performed on niobium clusters, including reactions with H 2 , N 2 , O 2 , CO, CO 2 , BrCN, and some selected organic compounds. − The trends in the reaction rates, − ,, reaction saturation limits, and, for some organic molecules, the degree of dehydrogenation (or conversion probability) 11-14 have been investigated. In our previous study on the reactions of Nb n + ( n = 2−13) with ethene, it was found that the reaction efficiency and the degree of dehydrogenation jumped from Nb 2 + to Nb 3 + .…”

Structures and Energetics of NH3 Adsorption and Decomposition at Nb(100) Surface: A Density Functional Study

“…As a first step in trying to understand this behavior, we have investigated the dissociation behavior of ammonia on a pure Nb surface. Recently, several studies on small Nb clusters have shown that Nb can be highly reactive with H 2 , H 2 O, and a variety of hydrocarbon compounds. , Goodwin and Salahub employed a density functional approach to study the binding energies and bond dissociation energies for small Nb clusters and achieved good agreement with experimental results . To understand the role of Nb in alloy surfaces in nitriding process, we utilized the DFT approach to study the chemisorption structures and energetics of the nitriding species.…”