Gas Phase Inorganic Chemistry

The field of gas phase inorganic ion chemistry is relatively new; the early studies date back approximately twenty years, but there has been intense interest and development in the field in the last ten years. As with much of modern chemistry, the growth in gas phase inorganic ion chemistry can be traced to the development of instrumentation and new experimental methods. Studies in this area require sophisticated instruments and sample introduc­ tion/ ionization methods, and often these processes are complicated by the need for state-selecting (or collisionally stabilizing) the reactive species in order to assign the chemistry unequivocally. At the present level of experimental development, a wide range of experiments on diverse ionic systems are possible and many detailed aspects of the chemistry can be studied. Gas Phase Inorganic Chemistry focuses on the reactions of metal ions and metal clusters, and on the study of these species using the available modern spectroscopic methods. Three of the twelve chapters cover the chemistry of ionic monometal transition metal ions and the chemistry of these species with small diatomics and model organics. Two of the chapters focus on the studies of the chemical and physical properties of (primarily) transition metal clusters, and these chapters review experimental methods and capabilities. Two chapters also deal with the chemistry of transition metal carbonyl clusters, and these chapters address issues important to cluster growth and activation as well as the characterization of such species.

1 Reactions of Atomic Metal Ions with H2, CH2, and C2H6: Electronic Requirements for H—H, C—H, and C—C Bond Activation.- 1. Introduction.- 1.1. Relation between Gas Phase and Condensed Phase.- 1.2. Electronic Requirements for Alkane Activation.- 1.3. State-Specific Chemistry.- 2. Ior Beam Techniques.- 2.1. Ion Sources.- 2.2. Experimental Considerations.- 2.3. Energy Behavior of Ion-Molecule Reactions.- 2.4. Comparison to ICR (FTMS) Techniques.- 3. Thermochemistry.- 3.1. From Endothermicities to Bond Energies.- 3.2. Ionic Metal Hydrides.- 3.3. Ionic Metal Methyls.- 3.4. Ionic MR2: R=H, CH3.- 3.5. Neutral Metal Methyls.- 3.6. Ionic Metal Methylidenes and Methylidynes.- 4. Reactions with Dihydrogen.- 4.1. Molecular Orbital Considerations.- 4.2. Spin Considerations.- 4.3. Periodic Trends in Reactivity.- 5. Reactions with Methane.- 5.1. Sc+ + CH4.- 5.2. Reaction Mechanism.- 5.3. Ti+, V+ + CH4.- 5.4. Cr+ + CH4.- 5.5. Fe+ + CH4.- 6. Reactions with Ethane.- 6.1. V+ + C2H6.- 6.2. Sc+ + C2H6.- 6.3. Fe+ + C2H6.- 6.4. Fe+ + C3H8.- 6.5. Zn+ + C2H6.- 7. Summary.- 7.1. Thermochemistry.- 7.2. Reactions with Dihydrogen.- 7.3. Reactions with Methane.- 7.4. Reactions with Ethane.- 7.5. Outlook.- References.- 2 Nucleophilic Addition Reactions of Negative Ions with Organometallic Complexes in the Gas Phase.- 1. Introduction.- 1.1. Nucleophilic Addition in Organometallic Chemistry.- 1.2. Previous Gas Phase Studies.- 2. The Flowing Afterglow Method.- 3. Mononuclear Transition Metal Carbonyls.- 3.1. Fe(CO)5.- 3.2. Group 5 and Group 6 Hexacarbonyls, M(CO)6 (M = V, Cr, Mo, W).- 3.3. Reactions with Partially Solvated Nucleophiles.- 4. Transition Metal Arene, Cyclopentadienyl, and Diene Complexes.- 4.1. (?6-C6H6)Cr(CO)3.- 4.2. (?5-C5H5)Mn(CO)3.- 4.3. Isomeric (C4H6)Fe(CO)3 Complexes.- 5. Catalysis Intermediates.- 5.1. Hydroxycarbonyl Complexes and the Homogeneously Catalyzed Water-Gas Shift Reaction.- 5.2. Hydride Transfer Reactions: Thermochemistry for Transition Metal Formyl Ions.- 6. Concluding Remarks.- References.- 3 Reactions in Ionized Metal Carbonyls: Clustering and Oxidative Addition.- 1. Mass Spectrometry of Metal Carbonyls.- 1.1. Binary Metal Carbonyls.- 1.2. Other Metal Carbonyls.- 1.3. Electronically Excited Fragment Ions.- 1.4. Negative Ion Mass Spectra.- 1.5. Thermochemistry of Fragment Ions.- 2. Clustering Reactions of Metal Carbonyl Ions with Metal Carbonyls.- 2.1. Early Results.- 2.2 Structure-Reactivity Relations in Clustering Reactions: Multiple Bonds in Iron Carbonyl Clusters.- 2.3. Structure-Reactivity Relations in Group 7 Metal Carbonyl Clusters: Large Polyhedral Structures.- 3. Ligand Substitution Reactions.- 4. Oxidative Addition Reactions of Atomic Transition Metal Ions.- 4.1. Reactions with Alkyl Halides and Alcohols.- 4.2. Reactions with Aryl Halides.- 4.3. Reactions with Alkanes.- 4.4. The Effect of Oxidation State: Reactions of Fe+, FeI+, and FeI2+.- 4.5. Reactions of Fe+ with Cycloalkanes: Transition State Geometries.- 5. Reactions of Polynuclear Metal Carbonyl Ions with Alkanes ..- 5.1. Reaction of Diatomic Metal Carbonyl Ions.- 5.2. Reactions of Rhenium Carbonyl Cluster Ions with Cycloalkanes.- References.- 4 Structure-Reactivity Relationships for Ionic Transition Metal Carbonyl Cluster Fragments.- 1. Electron Deficiency Model.- 2. Cluster Valence Molecular Orbital Model.- 3. Bonding of Fe(CO)x in Heterometallic Ionic Cluster Fragments.- 4. Metal-Metal and Metal-Ligand Binding Energies in Ionic Cluster Fragments of Transition Metal Carbonyls.- References.- 5 Metal and Semiconductor Cluster Ions.- 1. Introduction.- 2. Methods for Generating Cluster Ions.- 3. Methods for Studying Cluster Ions.- 4. Carbon Cluster Ions.- 5. Silicon Cluster Ions.- 6. Aluminum Cluster Ions.- 7. Transition Metal Cluster Ions.- 8. Concluding Discussion.- References.- 6 Atomic Clusters in the Gas Phase.- 1. Atomic Cluster Properties and Their Size Dependence.- 1.1. Interest in Atomic Clusters.- 1.2. N-Specific Properties.- 1.3. Theoretical Guidelines.- 2. Controlled Preparation (Synthesis) of Atomic Clusters.- 2.1. Requirements for Property Measurement.- 2.2. The Existing Methods.- 2.3. Comparison among Methods.- 3. The Basic Experimental Measurements.- 3.1. N-Specific Detection of Measured AN Properties.- 3.2. Natural Abundances and Cluster Growth Rates.- 3.3. The Ionization Potential and Electron Affinity.- 3.4. Electric and Magnetic Moments.- 3.5. Optical Spectroscopy.- 3.6. Photoelectron Spectroscopy (PES).- 3.7. Chemical Flow Reactors and Ion-Molecule Reactors.- 4. Review of Results.- 4.1. Main-Group Metals (Groups 1, 2, and 13).- 4.2. Noble Metal Clusters (Groups 11 and 12).- 4.3. Clusters of Transition Metal Atoms.- 4.4. Clusters of Groups 14 and 15 Elements.- 4.5. Rare-Gas Clusters.- 5. Prospectus: Outstanding Questions.- 5.1. Where Are the Isomers?.- 5.2. The Energetics of Chemical Reactions.- 5.3. Back to the Support.- References.- 7 Time-Resolved Kinetics of Organometallic Reactions in the Gas Phase by Transient Infrared Absorption Spectrometry.- 1. Introduction.- 2. Methods for the Detection and Infrared Spectral Characterization of Organometallic Intermediates in the Gas Phase.- 2.1. Pulsed UV Photolysis Sources.- 2.2. Infrared Sources.- 2.3. Infrared Detectors and Signal Processing Electronics.- 2.4. Experimental Setup for Gas Phase Transient Infrared Absorption Using an Incoherent Source.- 3. Review of Recent Progress in Gas Phase Organometallic Transient Infrared Absorption Spectroscopy.- 3.1. Fe(CO)5.- 3.2. Fe(CO)4(C2H4).- 3.3. Fe(CO)3(C2H4)2.- 3.4. Mn2(CO)10.- 3.5. Co(CO)3NO.- 3.6. Cr(CO)6.- 4. Time-Resolved Infrared Absorption Spectroscopy as a Probe of Dissociative CO-for-C2H4 Substitution in Cr(CO)4(C2H4)2.- 4.1. Background.- 4.2. Results and Discussion.- References.- 8 Characterization of Metal Complex Positive Ions in the Gas Phase by Photoelectron Spectroscopy.- 1. Introduction.- 2. Structural Information on Metal Positive Ions with Small Molecules in the Gas Phase.- 2.1. Background.- 2.2. Vibrational Fine Structure and Bond Distances in Metal Carbonyls.- 2.3. Jahn-Teller Effects and Angular Distortions in Metal Complex Positive Ions.- 3. Electron Distribution and Bonding in the Positive Ion.- 4. Ionization Energy-Bond Energy Relationships.- 4.1. Fundamental Relationships.- 4.2. Mn(CO)5 Bound to H, CH3, and Mn(CO)5.- 4.3. Electronic Factors of Carbon-Hydrogen Bond Activation.- References.- 9 Chemistry and Photochemistry of Bare Metal Cluster Ions in the Gas Phase.- 1. Introduction.- 2. Bimolecular Reactions of Metal Cluster Ions.- 2.1. Dissociative Chemisorption.- 2.2. Reactions with Organic Compounds.- 2.3. Oxide Chemistry.- 3. Unimolecular Reactions of Metal Cluster Ions.- 3.1. Photodissociation.- 3.2. Collision-Induced Dissociation and Unimolecular Dissociation.- 3.3. Multiply Charged Clusters.- 4. Conclusion.- References.- 10 Photodissociation of Metal-Containing Gas Phase Ions.- 1. Introduction.- 2. Experimental Methods.- 2.1. Ion Traps.- 2.2. Ion Beams.- 2.3. Clusters.- 3. Spectroscopy.- 3.1. What Color Are the Ions?.- 3.2. Organometallic Ions with Reasonably Complete Ligand Shells.- 3.3. Organometallic Ions with Major Coordinative Unsaturation.- 3.4. Diatomic Ions.- 3.5. Cluster Ions.- 4. Dissociation Products.- 4.1. What Do the Fragments Tell Us?.- 4.2. Ion Structures.- 4.3. Thermochemistry and Bond Strengths.- 4.4. Cluster Ions.- 5. Mechanistic Aspects.- 5.1. Probing the Details of the Photodissociation Process.- 5.2. Competitive Fragmentation.- 5.3. Infrared Laser Photochemistry.- 5.4. Angular Dependence.- References.- 11 Photodissociation of Gas Phase Metal Clusters.- 1. Introduction.- 2. Techniques.- 2.1. Detection of Organometallic Photoproducts by Chemical Trapping.- 2.2. Detection of Organometallic Photoproducts by Ionization Techniques.- 2.3. Detection of Organometallic Photoproducts by Spectroscopic Techniques.- 3. Examples.- 3.1. The Photofragmentation of Group 6 Complexes.- 3.2. The Photofragmentation of Group 7 Complexes.- 3.3. The Photochemistry of Group 8 Complexes.- 4. Conclusions.- References.- 12 Tandem Mass Spectrometry and High-Energy Collisional Activation for Studies of Metal Ion-Molecule Reactions.- 1. Introduction.- 2. Review of Tandem Instruments.- 2.1. Sector Instruments.- 2.2. Triple Quadrupoles.- 2.3. Hybrid Instruments.- 2.4. Fourier Transform Instruments.- 2.5. Collision Energy Considerations.- 2.6. Energy-Resolved Mass Spectrometry.- 3. Applications of MS/MS in Metal Ion Chemistry.- 3.1. Ion Beam Studies.- 3.2. Triple-Quadrupole Studies.- 3.3. Flowing Afterglow Studies.- 3.4. High-Energy Collisional Activation.- 3.5. Metastable Ion Studies.- 4. Conclusions.- References.