Reactive Intermediate Chemistry

1042 INDEX

Matrix isolation (Continued) oxygen reactions, 423–425

ultraviolet-visible spectroscopy, 390–391 Matter wave functions, femtosecond laser pulses, coherence mechanism, 905–906

Mayr electrophilicity/nucleophilicity scales, carbocation reactivity, 28–29

McConnell equation, radical compound identification, electron spin resonance (ESR), 130–131

McLafferty rearrangement, organic radical ions, unimolecular reactions, 239

Mechanistic probes, radical identification/ characterization, 126–127

Meisenheimer complexes, aromatic nucleophilic substitution, carbanion intermediates, 104

Melatonin, nanosecond laser flash photolysis, 857–858

MeO(SiMe2)nOMe, single bond silylene insertions, 673

Merostabilization, triplet carbene delocalization, 387–388

Mesityl(bora)anthrylidene, singlet-triplet energy gap, preequilibrium mechanism, 399–400

Meta-benzynes naphthynes, 766–769

parent structure, 747–752 substituent effects, 760–762

‘‘Metal ketyls,’’ trivalent compounds as, 207 Metallonitrenium ions, generation methods,

612–614

Meta-substituted derivatives, phenylnitrene, 533–534

Metathesis, carbene synthesis, 569–570 Methane derivatives, carbon acidity-carbanion

basicity, sp3 carbanions, hybridized C–H bonds, 82–86

Methanesulfonyl azide, sulfonylnitrenes, 517 Methanol matrices, triplet carbenes, hydrogen

atom tunneling, 415–416 Methoxycarbene, carbon atom deoxygenation,

490–492 Methoxytrifluoromethylcarbene, stable singlet

carbenes, single electronically active heteroatomic substituents, 341–347

o-Methoxyphenylcarbene, benzene-carbon atom reactivity, 482–484

1-Methyl-1-cyclohexyl cation, stable ion chemistry, 7–8

Methyl azide, alkylnitrenes, 508–511 2-methyl-2-butene, singlet carbenes, carbene

mimics, 308–314 Methylcarbene, carbon mimics, 308–314

Methylcubanes

cubyl cations, hydrogen abstraction, 987–988 tert-butoxyl radicals, 998

Methyl diazomalonate, singlet carbenes, stepwise vs. concerted addition, 292–297

Methylene

addition and insertion reactions, 274 carbenic substituents, ZFS parameters, 386 carbon atom deoxygenation, 490–492

carbene formation, 490–492 carbon–hydrogen insertions, 298–302 electronic structure calculations, 963 electrophilicity, 289–291

gas phase spectroscopy, 507

hydrogen abstraction, chemically induced dynamic nuclear polarization (CIDNP), 407–408

hyperconjugation effects, 381 matrix isolation, 816

matrix isolation spectroscopy, 507

singlet carbene structure and bonding, 274–279 singlet-triplet separation, 504–506

stepwise vs. concerted addition, 293–297 steric effects, 379

structure and bonding, 274–279

triplet carbenes, chemically induced dynamic nuclear polarization (CIDNP) effects, 407

5-Methylenebicyclo[2.2.0]hex-2-ene, radical cation, 230

2-Methylenecyclopentane,1,3-diyls, synthesis and electron spin resonance (ESR) properties, 168, 179–181

Methylenecyclopropane ESR spectra, 174

ring closure chemistry, 175

Methyleneimine, singlet methylnitrene conversion, 507–511

Methylformate, carbon atom deoxygenation, 490–492

N-Methylglycine, carbon atom reactions, 471–472

Methyl iodide, femtosecond time scales, 908 Methylnitrene

alkylnitrenes, singlet-triplet separation, 507–511

ring expansion reactions, electronic structure calculations, 983–985

vinylnitrene structures, 521–522 Methylphenylcarbene, intramolecular tunneling

reactions, 420–421 2-Methylphenylcarbene

intramolecular tunneling reactions, 419–421 preequilibrium mechanism, 396

Methyl radicals

electron spin resonance (ESR), 131 femtosecond time scale, 908

Norrish I intermediate, 913–914 laser flash photolysis, 410–413 structure, 122

Methylsilylene, isomerism, 665–668 Methylvalerophenone, nanosecond laser flash

photolysis, 855–858

Michael addition, nucleophilic additions, carbanion intermediates, alkenes, 101–103

Microcanonical ensemble, potential energy surfaces (PES)

statistical approximations, 940–941 statistical kinetic models, 938 transition state hypothesis, 939

variational transition state theory (VTST), 943 Microchannel plate photomultiplier tube (MCP-

PMT), picosecond systems, 880–881 Microwave discharges, radical ions, matrix

isolation, 821–823

‘‘Migratory aptitudes,’’ singlet carbenes, intramolecular insertion reactions, 304–306

Milnacipran, carbene synthesis, diazo compounds, 574–575

MOLCAS software, multireference wave function calculations, 977

Molecular beams

carbon atom generation, 470 carbon atom reactivity, 493–494

Molecular connectivity

heterocyclic planar tetramethyleneethane derivatives, 188–191

m-quinone derivatives, 187–188

spin state preference, tetramethyleneethane (TME), 181–185

Molecular dynamics (MD), potential energy surfaces (PES)

basic principles, 943–947 future applications, 956–957

stepwise vs. concerted reaction, 928–931 Molecular fragments, non-Kekule´ molecules, 167 Molecular mechanics

potential energy surfaces (PES), molecular dynamics (MD) principles, 946–947

strain energy calculations, 719–721 tetramethyleneethane (TME), 184–185

Molecular orbital (MO) calculations density functional theory (DFT), 977–979 electronic structure calculations, 971–973 heterolytic radical additions, 153

organic radical ions

INDEX 1043

bifunctional/distonic radical ions, 231–234

bimolecular reactions, 249–250 future research applications, 261–262 p-donors, 215–218

protic, ionic, and polar solvents, 253–256

strained ring cations, 223–228 radical ion detection-observation,

211–214

radical stabilization energy and bond dissociation energy, 124–125

singlet carbenes

philicity addition reaction, 280–285 structure and bonding, 275–279

stable ion chemistry, 7–8 triplet carbenes, 377–378

Molecular oxygen, kinetically stabilized germylenes, 695–696

Molecular triplets, non-Kekule´ molecules, biradical vs. radical pairing, 173

Møller-Plesset second-order perturbation (MP2) carbon acidity-carbanion basicity, sp3

carbanions, hybridized C–H bonds, 80–86

cubyl cation formation, 985–987 electron correlation, 975

nitrenium ion classification, 636–638 Mononaphthylcarbenes, laser flash photolysis,

412–413 Monophenyldiazomethane, hydrogen atom

tunneling, 413–414

Monoradicals, Schlenk-Brauns hydrocarbons, 167

Monorotation, cyclopropane stereochemistry, 990–997

Monovalent carbon, fluorocarbon reactivity, 479 More O’Ferrall diagrams, nucleophilic substitution

azide ion at benzylic carbon, 48–53

concerted reaction mechanism, coupling and, 51–53

stepwise ionization and trapping, liberated intermediate, 50

stepwise preassociation reactions, 50–51 benzyl derivatives, 58

MP4SDTQ calculation, electron correlation, 975 MSAD scale, carbanion chemistry, 71

Mulliken charges, cubyl cation formation, 986–987

Multiconfigurational (MC) wave function electron correlation, 973–974

matrix isolation, ultraviolet-visible spectroscopy, 837–838

1044 INDEX

Multiconfigurational self-consistent field (MCSCF) calculation, CASSCF/CASPT2 calculations, 976–977

Multiple-site problems, hydrogen atom transfer kinetics, 416–417

Multiplet effect, radical identification/ characterization, chemical induced dynamic nuclear polarization (CIDNP) effects, 132–133

Multiplicity

organic radical ions, intra-pair reactions, 245–246

singlet and triplet states, silylenes and germylenes, 661–662

trimethylenemethane (TMM), ring closure chemistry, 176

Multireference wave functions, CASPT2 method, 977

Multistep reactions, radical structures, 134–140 chain reactions, 134–136

chain reaction velocities, 136–138 nonchain reaction sequences, 138–140

Myers cycloreversion, didehydrotoluene biradical, 771–773

Myers-Saito reaction, didehydroindenes, 770–773

Nanosecond laser flash photolysis basic principles, 847–849

data acquisition and processing, 851–852 decay kinetics analysis, 869

flow systems, 869 future applications, 868 kinetic studies, 853–854

probe technique, 858–864

quantum yields and extinction coefficients, 865–868

second-order processes, 864–865 kinetics, 869

shock waves, 869

time-resolved absorption techniques, 849–868 transient spectroscopy, 852–853

triplet carbenes, preequilibrium mechanism, 396

two-photon processes, 869

Nanosecond time-resolved infrared (TRIR) spectroscopy

carbonylnitrenes, 516–517

nitrene analysis, future applications, 551–552

nitrenium ions, 635 tetramethylenebenzene (TMB), 187 triplet carbenes

preequilibrium mechanism, 396 time-resolved spectroscopy,

392–394 Naphthalene

carbon atom reactivity, 475, 483–484 organic radical ions, bimolecular reactions,

247–250

overcrowded diarylsilylenes, 688–689 Naphthdiynes, 784 m-Naphthoquinomethane, non-Kekule´

molecules, electron spin resonance (ESR), 169–170

2-Naphthoylazide, carbonylnitrenes, 513–515

2-Naphthoylnitrene, triplet sensitization, 514–515

2-Naphthoylnitrenium ion, DNA damaging mechanisms, 641–644

1-Naphthylphenylcarbene, tunneling reactions, elevated temperatures, 422

Naphthylazides, naphthylnitrenes, 541–543 Naphthylcarbenes

annealing geometry, 390 geometrical isomerism, 389

triplet carbenes, isomerism, zero-field splitting, 389

2-Naphthylcarbenes, benzene-carbon atom reactivity, 483–484

2-Naphthyl(carbomethoxy)carbene, singlet-triplet equilibrations, 307–308

infrared spectroscopy (TRIR), 392 singlet-triplet energy gap, surface-crossing

mechanism, 400–401

time-resolved infrared spectroscopy (TRIR), 394

Naphthylnitrenes, structural properties, 540–543 2-Naphthylnitrenium ion, DNA damaging

reactions, 610–611 Naphthynes, 764–769

Natural abundance isotope effects, singlet carbene addition, transition state symmetry, 289–291

Natural bond orbitals (NBO), strained hydrocarbons, 728–729

Natural Bond Order (NBO) analysis, carbon acidity-carbanion basicity, hybridized C–H bonds

sp2/sp carbanions, 86–87 sp3 carbanions, 81–86

Natural product synthesis, nitrenium ion singletstate reactions, p nucleophiles, 626–628

n donors, organic radical ions, 218

Nd:YAG oscillator, picosecond lasers, 876–878 Raman spectroscopy, 881–882

Negative activation energies, singlet carbenes, addition rate constants and activation parameters, 288–289

Negative bond dissociation energy (BDE), trimethylene-methane (TMM) derivatives, 181

Negative hyperconjugation, carbon aciditycarbanion basicity, sp3 carbanions, hybridized C–H bonds, 82–86

Negative-ion photoelectron spectroscopy (NIPES) p-benzynes, 757–759

m-benzynes, 750–752

phenylnitrene, computational chemistry, 525–528

Neocarcinostatin, didehydroindenes, 769–773 Neophyl rearrangement, group transfer reactions,

156

Net absorption/emission, chemically induced dynamic nuclear polarization (CIDNP) effects, triplet carbenes, 406

Net polarization, chemically induced dynamic nuclear polarization (CIDNP) effects, triplet carbenes, 406

Neutral biradicals tetramethyleenethane, 183

trimethylenemethane (TMM), electron photodetachment photoelectron spectroscopy, 177–178

NH. See Imidogen Nitrenes

acylnitrenes, 511–520 alkylnitrenes, 507–511 aminonitrenes, 545–547

stable compounds, 547–548 carbonylnitrenes, 511–520

nitrene esters, 515–517 phosphorylnitrenes, 518–520 sulfonylnitrenes, 517–518

imidogen (NH), 502–507 gas-phase spectroscopy, 506

matrix isolation spectroscopy, 507 matrix isolation, 815–816

metal nitrenes, organic synthesis, 583–586 oxonitrenes, 547

phenylnitrene and derivatives, 522–540 azirine cyclization, 534–536 computational chemistry, 525–528 fluoro-substituted singlets, 536–538 intersystem crossing rates, 531–532 laser flash photolysis studies, 528–529 orthoand meta-substituted derivatives,

533–534

para-substituted derivatives, 532–533

INDEX 1045

pyridylcarbene interconversions, 538–534 singlet dynamics, 529–531

phosphinidines, 547–551 polycyclic arylnitrines, 540–544

biphenylnitrenes, 543–544 naphthylnitrenes, 540–543

polynitrenes, 544–545 structural properties, 502 vinylnitrenes, 520–522

Nitrenium ions

aryland heterarylnitrenium ions, 606–611 DNA damaging reactions, 640–644

definition and classification, 594 dications, definition, 597 generation techniques, 611–619

electrochemical methods, 618–619 photochemical methods, 614–618 thermal methods, 611–614

historical background, 599–603 matrix isolation, 824

parent, alkyland halonitrenium ions, 603–606 reaction mechanisms, 619–631

intersystem crossing, 631 singlet-state reactions

hydride donors, 628

n nucleophiles, 621–624 p nucleophiles, 624–628

singlet-state rearrangement/elimination, 619–621

triplet-state hydrogen atom transfer, 629–631

relevant properties, 597–599 spectroscopic/kinetic studies, 631–640

direct intermediate detection, 638–640 infrared/Raman spectra, 636–638 ultraviolet-visible spectra, 634–636

‘‘Nitreniumoids.’’ See Metallonitrenium ions Nitrile oxide, kinetically stabilized germylenes,

695–696

Nitriles, overcrowded diarylsilenes, 689 Nitrogen atoms

carbon atom generation, 470 nitrenium ions

DNA damaging mechanisms, 641–644 singlet-state reactions, p nucleophiles,

626–628

organic radical ions, n donors, 218 stable singlet carbenes

Lewis acids and bases reactions, 354–358 p-electron-donating heteroatom substituents

(D-C-D), 339–340 Nitrogen–chlorine homolysis, nitrenium ion

generation, 613–614

1046 INDEX

Nitrogen–hydrogen bonds

carbene synthesis, insertion reactions, 579 single bond silylene insertions, 669–671 singlet carbenes, philicity addition, 284–285 Nitrogen–nitrogen bond heterolysis, nitrenium ion generation, photochemical initiation,

617–618

Nitrogen–oxygen bond, nitrenium ion generation, 613–614

photochemical initiation, 615–618 Nitrones, radical identification, 127 Nitrosobenzene, carbon atom deoxygenation,

phenylnitrene formation, 492

Nitroso compounds, radical identification, 127 Nitroxyl radicals, stability and persistence,

125–126

n-p* transitions, triplet carbene oxygen reactions, 423–425

Noble gases, matrix isolation, 800

Nonbonding electrons, silylenes and germylenes, 662

Nonbonding molecular orbital (NBMO) coefficients

phenylnitrene, azirine cyclization, 534–536 tetramethyleneethane (TME), 182–183

Nonchain reactions, radical structures, 138–140 Nonclassical carbocations

chemical properties, 9–12 theoretical background, 6–7 X-ray crystallography, 14–15

Noncrossing rule, potential energy surfaces (PES), conical intersections, 934–937

Non-Kekule´ molecules basic properties, 166

connectivity theory examples, 187–191 m-quinone derivatives, 187–188

disjoint vs. parity-based predictions, 192–194 electron spin resonance (ESR)

biradical/radical pairing, 173

Curie’s law, ground-state multiplicity, 174 matrices, 172–174

randomly oriented samples, 168–170 zero-field splitting, immobilizing media,

172–173

future research issues, 194–196 high-spin intermediates, 194–195 historical background, 166 Hund’s rule, 167–170

long-lived (persistent) spin isomerism, 189–191 magnetization/magnetic susceptibility

measurement and interpretation, 191–192 molecular connectivity spin state, 181–185 Schlenk-Brauns hydrocarbons, 167

singlet-triplet gap, 170–171 spectroscopic structural analysis, 171 spin state structural preference, 170 tetramethylenebenzene, 185–187 tetramethyleneethane

gas-phase singlet-triplet separation, 183–185

heterocyclic planar derivatives, 188–189 molecular connectivity spin state,

181–185 trimethylenemethane

bimolecular trapping, 176–177

electron spin resonance (ESR), 174–175 ring closure chemistry, 175–176 ring-constrained derivatives, 179–181 single-triplet gap, electron photodetachment

photoelectron spectroscopy, 177–179 ‘‘Non-Koopmanns’’ states, organic radical ions,

p-donors, 215–218 ‘‘Non-least-motion’’ transition state, carbene-

alkene cycloaddition, 289–291 Nonstatistical dynamics, potential energy surfaces

(PES)

acetone radical cation, 950–952 2,3-diazabicyclo[2.2.1]hept-2-ene thermal

deazetization, 953–955 1,2,5-heptatriene rearrangement, 952–953 molecular dynamics (MD), 943–947 reactive intermediate dynamics, 947–949 symmetry parameters, 949–950 vinylcyclopropane rearrangement, 950

Nonstereospecific addition products, hydrogen atom tunneling, 413–414

2-Norbornyl cation, structure and properties, 10–12

Norbornadiene

carbon atom reactions, 476–477 organic radical ions

bimolecular reactions, 251–252 strained ring cations, 225–228

Norbornene, femtosecond time scale, retro-Diels- Alder reactions, 918

7-Norbornone, silylene multiple bond additions, 681–683

1-Norbornyl cation, alkoxycarbene fragmentation,

319

2-Norbornyl cation, alkoxycarbene fragmentation,

319

Norcaradiene, organic radical ions

protic, ionic, and polar solvents, 253–256 strained ring cations, 223–228

Norcaradienylidene, fluorocarbon reactivity, 479–484

Normal ylides, stable singlet carbenes, Lewis acid/ base reactions, 354–358

Norrish I intermediate

femtosecond time scale, 911–914 cyclobutanone photolysis, 914

trimethylene-methane (TMM), bimolecular trapping, 176–177

n-p transistion

silylenes and germylenes, electronic spectra, 663–665

stable dialkylgermylene, 692 stannylenes, 699

Nuclear charge effect, radical reactivity, bond dissociation energies (BDEs), 123–125 Nuclear-electron attraction, electronic structure

calculations, 968

Nuclear magnetic moments, chemically induced dynamic nuclear polarization (CIDNP) effects, triplet carbenes, 406

Nuclear magnetic resonance (NMR) carbanion chemical shiftts, 75–76 carbocation skeletal rearrangements, 8–9 isotopic perturbation of symmetry, 12–13

radical identification/characterization, chemical induced dynamic nuclear polarization (CIDNP) effects, 133

stable ion chemistry, 6–8 strained hydrocarbons, 736

triplet carbenes, hydrogen abstraction, chemically induced dynamic nuclear polarization (CIDNP), 406–408

Nuclear medicine

carbon atom generation, 465–466 nucleogenic carbon and, 465–466

Nuclear-nuclear repulsion, wave-function calculations, 968

Nuclear spin, radical compound identification, electron spin resonance (ESR), 129–131

Nucleogenic carbon, carbon atom generation, 465–466

Nucleophile olefin combination, aromatic substitution (photo-NOCAS) reaction, organic radical ions, anionic radical reactions, 257–259

Nucleophiles carbocation reactivity

addition reactions, 25–28 basic principles, 15–16 carcinogenesis, 33–34

metal carbene synthesis, 563–564 nitrenium ion singlet-state reactions

n nucleophiles, 621–624 p nucleophiles, 624–628

INDEX 1047

Nucleophilic additions

carbanion intermediates, alkenes, 101–103 organic radical ions

anionic radical reactions, 257–258 protic, ionic, and polar solvents,

251–256 singlet carbenes

carbene mimics, 313–314

philicity addition reaction, 281–285 rate constants and activation parameters,

287–289

stable singlet carbenes, Lewis acids and bases reactions, 354–358

Nucleophilic attack, stable singlet carbenes, dimerization reactions, 349–350

Nucleophilicity parameter, carbocation reactivity, Mayr’s scale, 28–29

Nucleophilic solvation, aliphatic tertiary carbons, 63–65

Nucleophilic solvent participation, aliphatic tertiary tcarbons, 62–63

Nucleophilic substitution benzylic carbon

basic principles, 44 borderline reactions, 53–58

concerted reaction mechanism, coupling and, 51–53

cumyl derivatives

borderline reactions, 55–57 ring-substituted derivatives, 45, 47–48

More O’Ferrall diagrams, 48–50 1-phenylethyl derivatives

borderline reactions, 53–55 ring-substituted derivatives, 44–47

stepwise ionization/trapping, liberated reaction intermediate, 50

stepwise preassociation, 50–51 carbanion intermediates

acyl substitution, 110–111 aromatic substitution, 103–104

heterolytic radical additions, 153

radical structures, homolytic hydrogen atom transfer, 145–146

tertiary carbon

reaction mechanisms, 59–62 solvent/solvation effects, 62–65

stepwise vs. concerted reaction mechanisms, 41–43

Nþ values, carbocation reactivity, 17

9,10-Octalin oxide, radical cation, 2301 Olefinic strain, strain energy calculations,

722–723

1048 INDEX

Olefins

germylene multiple bond addition, 679–680 persistent triplet carbenes, 440–441 silylene reactions, 677–680

singlet carbenes

addition rates and activation parameters, 285–289

philicity addition reaction, 279–285 stable singlet carbenes, ruthenium catalysts,

362–365 Oligosilanes

dimethylsilylene generation, 654–655 thermally induced silylene a-elimination and

photoextrusion, 652–660 branched cyclic silylsilanes, 657–658

cyclotrisilane/cyclotrigermane photolysis and thermolysis, 656–657

dimethylsilylene generation, polysilanes/ oligosilanes, 654–655

linear polysilane photolysis, 655–656 metal-induced eliminations, 658–660 polysilane/oligosilane thermolysis, 652–654

thermolysis, 652–654 One-electron wave function

Hartree-Fock calculations, 969–970 wave-function calculations, 968

Open-shell molecules, CASSCF/CASPT2 calculations, 976–977

Optical calorimetry, picosecond lasers, 885–886 p bond homolysis/heterolysis, 893–894

Optical spectroscopy (OS), organic radical ions detection-observation, 211–214

n donors, 218 p-donors, 215–218

Optoacoustic calorimetry, intra-pair reactions, 239 Orbital active space, CASSCF/CASPT2

calculations, 976–977

Orbitals, wave-function calculations, 968 Organic ferromagnetic compounds, triplet

carbenes, 376 Organic radical ions

cation reactions, 234–261 bimolecular reactions, 246–261

alkenes and aromatics, 246–250 like-charge ions, 259–261

protic, ionic, polar reagents, 250–256 radical anions, 256–259

intra-pair reactions, 239–246 reactive intermediates, 234–236 unimolecular reactions, 236–239

chemical origins, 205–209 detection-observation, 211–214 generation mechanisms, 209–211

structural properties, 214–234 bifunctional/distonic structures, 229–234 1,5-hexadiene systems, 228–229

n donors, 218

p donors, 215–218 s donors, 219–221

strained ring compounds, 221–228 Organolead compounds, plumbylenes, 699–705 Organolithium

carbanion chemistry, 70–71

magnetic properties and NMR, 75–76 stereochemistry and racemization, 73–74

carbon acidity-carbanion basicity, condensed-phase measurements, ion-pair acidities, 90–93

Organomagnesium, carbanion chemistry, 70–71 Ortho-substituted derivatives, phenylnitrene,

533–534 Ovchinnikov criterion

m-quinone derivative connectivity, 188 tetramethylenebenzene (TMB), 185–186

Oxadiazoline, singlet carbenes, philicity addition, 284–285

Oxasiliranes, silylene multiple bond additions, 680–683

Oxazirine, acylnitrenes, 515 Oxetane

bifunctional/distonic radical ions, 232–234 intra-pair reactions, 244–246

single bond silylene insertions, 671–673 Oxirane, radical cation, 231 Oxocarbocations, protic solvent lifetimes, 21

Oxocyclohexadienylidene, laser flash photolysis, 413

Oxonitrenes, structural characterization, 547 Oxonium ylide, triplet carbenes, chemically induced dynamic nuclear polarization

(CIDNP) effects, 408

Oxyalkyl diradicals, femtosecond time scale, 917

Oxychlorocarbene, matrix isolation, 817–818 16O18O isotopomers, triplet carbene oxygen

reactions, matrix isolation studies, 424–425

18O labeling

aliphatic nucleophilic substitution, tertiary carbons, 59–60

uncoupled concerted nucleophilic substitution, 56

Oxygen adduct, intra-pair reactions, 244–246 Oxygen atoms, organic radical ions

intra-pair reactions, 244–246 n donors, 218

Oxygen–hydrogen bonds

insertion, preequilibrium mechanism, 395 single bond silylene insertions, 669–671

Oxygen matrix, silylenes and germylenes, electronic spectra, 664–665

Oxygen molecules, triplet carbenes, 422–431

dimesitylketone oxide, 425–426 emission, 426–427

laser flash photolysis, 427–429

matrix isolation spectroscopy, 423–425 product studies, 423 tetramethylpiperidine N-oxide (TEMPO),

430–431

Oxygen-oxygen coupling, stable/persistent radicals, 125–126

Oxygen trapping, tetramethylenebenzene (TMB), 187

N-Oxyradicals, product inference, 127 Oxypentamethylene, femtosecond time scale,

oxyalkyl diradical/formylalkyl radical intermediates, 917

Pairing orbital theorem, organic radical ions, p-donors, 217–218

Para adducts, nitrenium ion singlet-state reactions, p nucleophiles, 626–628

Paracyclophanes, steric strain, 727 Paramagnetism

matrix resonance spectroscopy, 172 non-Kekule´ molecules, 191–192

Guoy balance technique, 167–168 Para, para’-disubstituted diphenylcarbenes,

ZFS parameters, 388 Para substituents

halogen-protected diphenylcarbenes, 446–447

phenylnitrene, 532–533 triplet carbenes

halogen-protected diphenylcarbenes, 446–447

zero-field splitting, 386–388 Parent carbene, evolution of, 329 Parent nitrenium ions

electronic configuration, 603–606 hydrogen atom transfer, 630–631

Parity-based predictions

non-Kekule´ molecules, disjoint biradicals, 192–194

tetramethylene-ethane, 182–183

Pauli exclusion principle, electronic structure calculations, 968

Pd(PPh3)4, silylene multiple bond addition, 677

INDEX 1049

1,4-pentadiene, femtosecond time scale, trimethylene/tetramethylene diradicals, 916

Pentamethylcyclopentadienyl ligands, synthesis and isolation, 684–687

Pentamethylenepropane (PMP), disjoint vs. paritybased predictions, 192–194

3-Pentanone, femtosecond time scale, Norrish I intermediate, 913–914

Perchlorophenyl groups, halogen-protected diphenylcarbenes, 445–447

Perfluorophenyl nitrene fluoro-substituted phenylnitrenes,

536–538

sp lone pair transitions, 527–528 Peri-hydrogens, triplet polynuclear aromatic

carbenes, 448–449

Perinaphthadiyl diradicals, matrix isolation, 820 Perpendicular geometry, triplet polynuclear

aromatic carbenes, 448–449 Persistent radicals

nonchain radical reaction sequence, 138–140 structure and reactivity, 125–126

Persistent triplet carbenes, structural analysis, 439–452

alkyl-protected diphenylcarbenes, 441–444 halogen-protected diphenylcarbenes, 444–447 high-spin polycarbenes, 449–452 polynuclear aromatic carbenes, 448–449 trifluoromethyl-protected diphenylcarbenes,

447–448

Perturbation theory, electron correlation, 974–975 Ph2Nþ, nitrenium ion rearrangement/elimination,

620–621

Phase space, potential energy surfaces (PES), statistical kinetic models, 937–938

Phenalene, carbon acidity-carbanion basicity, sp3 carbanions, hybridized C–H bonds, 85–86 Phenols, benzene-carbon atom reactivity, 481–484

1,2-Phenyl migrations, carbanion intermediates, rearrangements, 106–107

Phenylallene, carbon-alkene reactions, 474 Phenyl azide, phenylnitrene, 523–525

azirine cyclization, 534–536 computational chemistry, 526–528 laser flash photolysis (LFP), 528–529

Phenylcarbene

B3LYP/6-31G calculations, 379–380 carbenic substituents, ZFS parameters, 386 carbon atom reactivity, benzene/substituted

benzene, 479–484

incarcerated carbene chemistry, 314–317 matrix isolation, 835–836

1050 INDEX

Phenylcarbene (Continued) phenylnitrene, intersystem crossing, 532 phenylnitrene computational chemistry,

525–528 phenylphosphinidine, 548–551

ring expansion reactions, electronic structure calculations, 982–985

structural chemistry, 522–525 Phenyl(chloro)carbene

hydrogen atom tunneling, 415–416 hydrogen tunneling, 417–419

C-Phenyl-N-tert-buylnitrone (PBN), radical identification/characterization, 127

1-Phenylcyclohexene, radical cation reactions,

251

Phenylcyclopropane, organic radical ions, strained ring cations, 222–228

p-Phenylenediamine, organic radical ion chemistry, 207–209

1-Phenylethyl derivatives (X-1-Y), nucleophilic substitution, benzylic carbon

borderline reactions, 53–55 More O’Ferrall diagrams, 48–50

ring-substituted derivatives, 44–47 1-Phenylethylidene, triplet carbenes,

intramolecular hydrogen tunneling, 420–421

3-Phenylindane

alkyl-protected triplet diphenylcarbenes, 441–444

triplet diphenylcarbene protection, 441–444 Phenyl(methoxycarbonyl)carbene, laser flash

photolysis, 412–413 Phenylnitrene

azirine cyclization, 534–536 azobenzene formation, 517–518

carbon atom deoxygenation of nitrosobenzene, 492

computational chemistry, 525–528 fluoro-substituted singlets, 536–538 intersystem crossing rates, 531–532 laser flash photolysis studies, 528–529 orthoand meta-substituted derivatives,

533–534

para-substituted derivatives, 532–533 phosphinidines, 548–551

pyridylcarbene interconversions, 538–534 ring expansion reactions, electronic structure

calculations, 982–985 singlet dynamics, 529–531

structural characterization, 522–525 Phenylnitrenium ions

computational studies, 606–607

DNA damaging reactions, 610–611 7-Phenyl-7-norbornenyl cation, nonclassical

structure, 11 Phenylphosphinidine

ring expansion reactions, electronic structure calculations, 982–985

singlet ground state, 548–551 Phenyl(trifluoromethyl)carbene, hydrogen

tunneling, 417–419 Philicity

carbene synthesis, 562

singlet carbene addition, 279–285 addition rate constants and activation

parameters, 289 structure-reactivity relationships, 289

triplet carbenes, matrix isolation studies, 425 Phillips triolefin process, carbene synthesis, 563 Ph(Me3Si)SiCl2, single bond silylene insertions,

669–671

Phosgene, carbon atom deoxygenation, 490–492 Phosphacyclopropanes, phenylphosphinidine,

550–551

Phosphalkynes, overcrowded diarylsilenes, 689 Phosphapropyne, phosphinidenes, 548 Phosphasilylcarbenes, singlet carbenes, philicity

addition, 284–285

Phosphinidines, structural properties, 547–551 Phosphino carbenes

stable singlet carbenes dimerization reactions, 350

single electronically active heteroatomic substituents, 344–347

transition metal complexes, 359 (Phosphino)(phosphonio)carbenes, stable singlet

carbene state, p-electron-donating- electron-withdrawing heteroatom substituent (D-C-W), 335–338

(Phosphino)(silyl)carbenes direct complexes, 359 stable singlet carbenes

cyclopropanation, 351–354

Lewis acids and bases reactions, 357–358 stable singlet carbene state, 332–334

p-electron-donating-electron-withdrawing heteroatom substituent (D-C-W), 335–338

Phosphorus substituents, singlet carbenes, addition rate constants and activation parameters, 288–289

Phosphorylnitrene, 518–520 Photoaffinity labeling

fluoro-substituted phenylnitrenes, 536–538 nitrene research, 551–552

nitrenes, 502

Photochemical decomposition, singlet carbenes, carbene mimics, 310–314

Photochemical initiation

nitrenium ion generation, 614–618 organic radical ions, 206–209

radical closed-shell structures, photolysis, 142–143

Photoelectron spectroscopy (PES) carbanion geometric structure, 72 carbon acidity-carbanion basicity, bond

strengths, 96–97

N-heterocyclic carbenes (NHC), 360–362 nitrenium ions, parent, alkyland halonitrenium

ions, 605–606 non-Kekule´ molecules, 2,4-

dimethylenecyclobutane diyl, 170 organic radical ions

bifunctional/distonic radical ions, 229–234 bimolecular reactions, 248–250

cation reactive intermediates, 235–236 detection-observation, 211–214 intra-pair reactions, 239–246

n donors, 218 p-donors, 215–218

protic, ionic, and polar solvents, 251–256 strained ring cations, 226–228

trimethylene-methane (TMM), singlet-triplet separation, 177–179

Photoextrusion, thermally induced silylenes, 652–660

Photoheterolysis, carbocation reactions, 18–21 Photoinduced electron transfer (PET)

radical closed-shell structures, photolysis, 142–143

radical ion generation, 210–211 Photolysis

cyclobutanone, femtosecond time scale, 914 cyclotrisilanes/cyclotrigermanes, 656–657 linear polysilanes, 655–656

picosecond spectroscopy, tert-butyl 9-methyl-9- fluoreneperoxycarboxylate, 891–892

radical initiation, closed-shell compounds, 142–143

triplet carbenes

chemically induced dynamic nuclear polarization (CIDNP) effects, 408

diazo compounds, 383–384 hydrogen atom abstractions, 404

Photooxidation, triplet carbenes, product studies, 423

Photoprotanation

carbocation generation, 19–21 matrix isolation, 824

INDEX 1051

Photoreactivation, DNA molecules, 239 Photoresists, nitrenes, 502 Photosolvolysis, carbocation reactivity, 19 Picosecond lasers

fluorescence spectroscopy, 880–881 streak camera detection, 880 time-correlated single-photon counting,

880–881

infrared absorption spectroscopy, 883–885 >1500-cm 1 region, 883–884 fingerprint region, 884–885

optical calorimetry, 885–886 Raman spectroscopy, 881–882 reactive intermediates, 886–894

tert-butyl 9-methyl-9- fluoreneperoxycarboxylate photolysis, 891–892

p-bond homolysis/heterolysis, 892–894 p-conjugated excited states, 886–891

diphenylacetylene, 890–891 1,4-diphenyl-1,3-butadiene, 888–889 1,2-diphenylethene (stilbene), 886–887 1,6-diphenyl-1,3,5-hexatriene, 889–890

research background, 874–875 triplet carbenes

excited states, 435–437

laser flash photolysis, 412–413 preequilibrium mechanism, 396

ultraviolet-visible absorption spectroscopy, 875–880

dye lasers, 878–880

solid-state laser systems, 876–878 p-acceptor substituents, triplet carbenes, preequilibrium mechanism, 398

p bonds

germylene multiple bond addition, 679–680 homolysis/heterolysis, picosecond

spectroscopy, 892–894 nitrenium ion detection, 638–649 p-CI quantum chemical computation,

tetramethylenebenzene (TMB), 186–187 p-conjugated systems

nonclassical carbocations, 9–12 non-Kekule´ molecules

basic properties, 166 Hund’s rule, 167–168

reactive intermediates, picosecond lasers, 886–891

diphenylacetylene, 890–891 1,4-diphenyl-1,3-butadiene, 888–889 1,2-diphenylethene (stilbene), 886–887 1,6-diphenyl-1,3,5-hexatriene, 889–890

tetramethyleneethane, 182–183