Synthesis and Qualitative Olfactory Evaluation of Benzodioxepine Analogues

Marine fragrances, particularly Calone 1951^® (=7‐methyl‐2H‐1,5‐benzodioxepin‐3(4H)‐one; 1 ) has carved a minor but distinct niche in the broad field of fragrance chemistry. By focusing on the polar structure fragment of the benzodioxepinone parent compound, we set out to determine the molecular influence on the dominant marine note attributed to the Calone 1951^® structure. A selection of one‐step modifications of the ketone 1 resulted in a range of odor‐active conformers with diverse olfactory attributes. The synthesis of a range of benzodioxepine analogues, i.e., of 3 – 11 , is presented alongside olfactory evaluation (Tables 2 and 3). Removal of the carbonyl group of 1 and increasing the size of the aliphatic ring portion (see 6 and 7 ) introduced sweetness and a predominant loss of the marine character.     

Supramolecular Ammine-Copper rac-BINOLAT Salts through in-situ R- or S-BINOL Racemization

The molecule rac-1,1'-binaphthalene-2,2'-diol (rac-1,1'-bi-2-naphthol, rac-BINOL) shows a propensity for supramolecular, charge-assisted O–H ··· O^– hydrogen-bonded strand formation when crystallized with its deprotonated form BINOLAT^2– and Cu²⁺ in conc. ammonia. The naphthyl-paneled cavities in the {(rac-BINOLAT^2–)(rac-BINOL)₂} strands host the [Cu(NH₃)₅]²⁺-guest cation through second-sphere N–H ··· O hydrogen bonding in the structure of [Cu(NH₃)₅]²⁺(rac-BINOLAT^2–)(rac-BINOL)₂. Decreasing the copper(II) and ammonia concentrations in the crystallization leads to {(rac-BINOLAT^2–)(rac-BINOL)} strands, in which rac-BINOLAT^2– coordinates to two copper(II) atoms in the structure of [Cu(NH₃)₂(μ-rac-BINOLAT^2–-κ²O,O':κO)]₂(rac-BINOL)₂. In the {Cu²⁺(NH₃)₂} moiety two BINOLAT-oxide atoms act as bridging ligands. Both copper structures could be obtained by using the racemic rac-BINOL or the enantiomeric R- or S-BINOL, through an in-situ racemization of the latter.     

Cesium Ion-Selective Electrode

The membrane material was prepared by mixing 40% of cesium-triphenyl-cyanoborate and 60% of PVC powder. The mixture was pressed at a pressure of 20tons/cm² for 1hours to make the membrane. Then, the membrane was mounted on a self-constructed electrode body. Nernstian slope of 60 mv/decade was obtained throughout the concentration range 10^?1～2×10^?5M. Selectivity coefficients were presented. The life time of the electrode is longer than 6 months.     

Synthesis of Benzodioxepinone Analogues via a Novel Synthetic Route with Qualitative Olfactory Evaluation

Marine odorants represent a minor yet diverse class of substances within the fragrance industry, of which 7‐methyl‐2H‐1,5‐benzodioxepin‐3(4H)‐one ( 1 ) is commercially known as Calone 1951^®, a synthetic first in the area of marine‐fragrance chemistry. To determine the extent to which the characteristic marine odor of Calone 1951^® corresponds to the substitution at the benzo portion of the molecule, a variety of aromatic substituents were incorporated into the benzodioxepinone structure (Scheme 1, Table 3). In light of the difficulty experienced in applying patented literature to deriving the analogues 12 – 18 , particularly those with electron‐withdrawing substituents, an alternative synthetic scheme was implemented for the construction of all analogues in favorable yields (Scheme 4, Table 3). Formation of the hydroxy‐protected dihalo alkylating agent 24 via epoxide cleavage of epichlorohydrin (Scheme 3) allowed etherification favoring dihalo displacement and subsequent intramolecular ring closure (→ 26a – g ). THP Deprotection followed by oxidation of the alcohols 27a – g to the ketones 12 – 18 provided a general pathway to the benzodioxepinone products. The influence of the substituent nature on odor activity revealed a diverse scope of olfactory character (Table 4).     

Shear Viscosity of Dilute Polymer Solutions Compared and Contrasted with Mechanical Properties of Nylon Plus Plasticizer

Abstract

Both the shear viscosity η(c) of dilute polymer solutions and Young's modulus Y(c) of nylon plus plasticizer with concentration c are assumed to be expressible as a power series in concentration. Scaling arguments are then presented which reveal an intimate relation between the coefficients of O(c) and O(c²) terms in both η(c) and Y(c) The coefficient of the O(²) term is predicted always to be positive, while that of the O(c) term can in principle have either sign. Comparison with experiment is made for η(C) and Y(c) Some further experiments are proposed for both Y(c) and η(c)     

Pyridine‐Enhanced Head‐to‐Tail Dimerization of Terminal Alkynes by a Rhodium–N‐Heterocyclic‐Carbene Catalyst

A general regioselective rhodium‐catalyzed head‐to‐tail dimerization of terminal alkynes is presented. The presence of a pyridine ligand (py) in a Rh–N‐heterocyclic‐carbene (NHC) catalytic system not only dramatically switches the chemoselectivity from alkyne cyclotrimerization to dimerization but also enhances the catalytic activity. Several intermediates have been detected in the catalytic process, including the π‐alkyne‐coordinated Rh^I species [RhCl(NHC)(η²‐HC?CCH₂Ph)(py)] ( 3 ) and [RhCl(NHC){η²‐C(tBu)?C(E)CH?CHtBu}(py)] ( 4 ) and the Rh^III–hydride–alkynyl species [RhClH{? C?CSi(Me)₃}(IPr)(py)₂] ( 5 ). Computational DFT studies reveal an operational mechanism consisting of sequential alkyne C? H oxidative addition, alkyne insertion, and reductive elimination. A 2,1‐hydrometalation of the alkyne is the more favorable pathway in accordance with a head‐to‐tail selectivity.     

Step‐Growth Polymerizing Systems of General Type “AfiBgi”: Calculating the Radius of Gyration and the g‐Curve Using Generating Functions and Recurrences

Step‐growth polymerized systems of general type “AfiBgi” are considered. One or more of the monomer species carries at least three reactive groups and thus can act as a branching point in a polymeric molecule. An algorithmic method is presented to calculate the topology‐averaged square radius of gyration, R ²[s ], of the molecules in the class of s‐mers. The degree of polymerization, s , may run through its full range. In addition to R ²[s ], the shrinking factor, g [s ], is calculated. The method uses integer arithmetic, generating functions, and computer algebra.

     

Osmium(III) and Osmium(V) Complexes Bearing a Macrocyclic Ligand: A Simple and Efficient Catalytic System for cis‐Dihydroxylation of Alkenes with Hydrogen Peroxide

A simple protocol that uses [Os^III(OH)(H₂O)(L ‐N₄Me₂)](PF₆)₂ ( 1 ; L ‐N₄Me₂=N,N′‐dimethyl‐2,11‐diaza[3.3](2,6)pyridinophane) as a catalyst and H₂O₂ as a terminal oxidant for efficient cis‐1,2‐dihydroxylation of alkenes is presented. Unfunctionalized (or aliphatic) alkenes and alkenes/styrenes containing electron‐withdrawing groups are selectively oxidized to the corresponding vicinal diols in good to excellent yields (46–99 %). In the catalytic reactions, the stoichiometry of alkene:H₂O₂ is 1:1, and thus the oxidant efficiency is very high. For the dihydroxylation of cyclohexene, the catalytic amount of 1 can be reduced to 0.01 mol % to achieve a very high turnover number of 5500. The active oxidant is identified as the Os^V(O)(OH) species ( 2 ), which is formed via the hydroperoxide adduct, an Os^III(OOH) species. The active oxidant 2 is successfully isolated and crystallographically characterized.     

Synthesis and Spectroscopic Characterization of Novel Aryl-Dithiofluorophosphonate Derivatives and X-Ray Studies of [(4-CH3OC6H4)(F)P(S)S−][PH4P+]

Abstract

Potassium and tetraphenylphosphonium salts of novel aryldithiofluorophosphonic acids were synthesized. Lawesson's Reagent was allowed to react with KF in acetonitrile to yield the potassium salt of p-methoxyphenyldithiofluorophosphonic acid. Treatment of the latter with tetraphenylphosphonium chloride resulted in the formation of the tetraphenylphosphonium salt. The structures of the compounds were elucidated by FTIR, ¹H, ¹³C, ¹⁹F, and ³¹P NMR spectroscopy as well as by ESI-mass spectrometry. The molecular and crystal structure of the tetraphenylphosphonium salt, determined by single crystal X-ray diffraction, is also presented.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Reductive Dimerization of Triruthenium Clusters Containing Cationic Aromatic N‐Heterocyclic Ligands

The cationic cluster complexes [Ru₃(μ‐H)(μ‐κ²N,C‐L¹ Me)(CO)₁₀]⁺ ( 1 ⁺; HL¹ Me=N‐methylpyrazinium), [Ru₃(μ‐H)(μ‐κ²N,C‐L² Me)(CO)₁₀]⁺ ( 2 ⁺; HL² Me=N‐methylquinoxalinium), and [Ru₃(μ‐H)(μ‐κ²‐N,C‐L³ Me)(CO)₁₀]⁺ ( 3 ⁺; HL³ Me=N‐methyl‐1,5‐naphthyridinium), which contain cationic N‐heterocyclic ligands, undergo one‐electron reduction processes to become short lived, ligand‐centered, trinuclear, radical species ( 1 – 3 ) that end in the formation of an intermolecular C? C bond between the ligands of two such radicals, thus leading to neutral hexanuclear derivatives. These dimerization processes are selective, in the sense that they only occur through the exo face of the bridging ligands of trinuclear enantiomers of the same configuration, as they only afford hexanuclear dimers with rac structures (C₂ symmetry). The following are the dimeric products that have been isolated by using cobaltocene as reducing agent: [Ru₆(μ‐H)₂{μ₆‐κ⁴N₂,C₂‐(L¹ Me)₂}(CO)₁₈] ( 5 ; from 1 ⁺), [Ru₆(μ‐H)₂{μ₆‐κ⁴N₂,C₂‐(L² Me)₂}(CO)₁₈] ( 6 ; from 2 ⁺), and [Ru₆(μ‐H)₂{μ₄‐κ⁸N₂,C₆‐(L³ Me)₂}(CO)₁₈] ( 7 ; from 3 ⁺). The structures of the final hexanuclear products depend on the N‐heterocyclic ligand attached to the starting materials. Thus, although both trinuclear subunits of 5 and 6 are face‐capped by their bridging ligands, the coordination mode of the ligand of 5 is different from that of the ligand of 6 . The trinuclear subunits of 7 are edge‐bridged by its bridging ligand. In the presence of moisture, the reduction of 3 ⁺ with cobaltocene also affords a trinuclear derivative, [Ru₃(μ‐H)(μ‐κ²N,C‐L^3′ Me)(CO)₁₀] ( 8 ), whose bridging ligand (L^3′ Me) results from the formal substitution of an oxygen atom for the hydrogen atom (as a proton) that in 3 ⁺ is attached to the C⁶ carbon atom of its heterocyclic ligand. The results have been rationalized with the help of electrochemical measurements and DFT calculations, which have also shed light on the nature of the odd‐electron species, 1 – 3 , and on the regioselectivity of their dimerization processes. It seems that the sort of coupling reactions described herein requires cationic complexes with ligand‐based LUMOs.     

NMR Signal Assignment of 22-Deoxocucurbitacin D and Cucurbitacin D from <Emphasis Type="Italic">Ecballium elaterium</Emphasis> L. (Cucurbitaceae)

Summary. ¹H and ¹³C NMR signal assignments derived from 2D NMR experiment based correlations are presented for 22-deoxocucurbitacin D and cucurbitacin D. Both derivatives have been isolated from Ecballium elaterium L. (Cucurbitaceae).     

Synthesis and Insertion Chemistry of Mixed Tether Uranium Metallocene Complexes

The synthesis of mixed tethered alkyl uranium metallocenes has been investigated by examining the reactivity of the bis(tethered alkyl) metallocene [(η⁵‐C₅Me₄SiMe₂CH₂‐κC)₂U] ( 1 ) with substrates that react with only one of the U? C linkages. The effect of these mixed tether coordination environments on the reactivity of the remaining U? C bond has been studied by using CO insertion chemistry. One equivalent of azidoadamantane (AdN₃) reacts with 1 to yield the mixed tethered alkyl triazenido complex [(η⁵‐C₅Me₄SiMe₂CH₂‐κC)U(η⁵‐C₅Me₄SiMe₂‐CH₂NNN‐Ad‐κ²N^1,3)]. Similarly, a single equivalent of CS₂ reacts with 1 to form the mixed tethered alkyl dithiocarboxylate complex [(η⁵‐C₅Me₄SiMe₂CH₂‐κC)U(η⁵‐C₅Me₄SiMe₂‐ CH₂C(S)₂‐κ²S,S′)], a reaction that constitutes the first example of CS₂ insertion into a U⁴⁺? C bond. Complex 1 reacts with one equivalent of pyridine N‐oxide by C? H bond activation of the pyridine ring to form a mixed tethered alkyl cyclometalated pyridine N‐oxide complex [(η⁵‐C₅Me₄SiMe₂CH₂‐κC)(η⁵‐C₅Me₄SiMe₃)U(C₆H₄NO‐κ²C,O)]. The remaining (η⁵‐C₅Me₄SiMe₂CH₂‐κC)^2? ligand in each of these mixed tethered species show reactivity towards CO and tethered enolate ligands form by insertion. Subsequent rearrangement have been identified in [(η⁵‐C₅Me₄SiMe₃)U(C₅H₄NO‐κ²C,O)(η⁵‐C₅Me₄SiMe₂C(?CH₂)O‐κO)] and [(η⁵‐C₅Me₄SiMe₂CH₂NNN‐Ad‐κ²N^1,3)U(η⁵‐C₅Me₄SiMe₂C(?CH₂)O‐κO)].     

Synthesis,Characterization and Crystal Structure of Chlorodibenzyltin（Ⅳ） Complex with Dithiomorpholinocarba—mate Ligand

Chlorodibenzyltin (IV) complex with dithiomorpholinocarbamate ligand was synthesized by the reaction of dibenzyltin dichloride with dithiomorpholinocarbamate in 1:1 stoichiometry. The complex was characterized by elementary analysis, UV, BR and ¹H NMR spectra. The crystal structure was determined by X‐ray single crystal diffraction study. The crystallographic data are as follows: triclinic, space group P1 , a = 0.8723 (2) ran, b = 1.099 (2) nm, c = 1.1036 (3) nm, α = 86.498 (4)°, β = 89.697 (5)°, γ = 82.807 (5)°, Z = 2, V = 1.0479 (4) nm³, D_c= 1.580 g/cm^?3, μ = 1.553 mm^?1, F (000) = 500, R₁ = 0.0442, wR₂ = 0.0974. The crystal consists of discrete molecules containing five‐coordinate tin atoms in a distorted tigonal bipyramidal configuration. The molecules are packed in the unit cell in one‐dimensional chain structure through a weak interaction between the chlorine atom and sulfur atom, the sulfur atom and one of the sulfurs of an adjacent molecule.     

Theoretical prediction on HBeN− and HNBe− anions using multiconfiguration second‐order perturbation theory

The HBeN^? and HNBe^? anions have been investigated for the first time using the CASSCF, CASPT2, and DFT/B3LYP methods with the contracted atomic natural orbital (ANO) and cc‐pVTZ basis sets. The geometries of all stationary points along the potential energy surfaces were optimized at the CASSCF/ANO and B3LYP/cc‐pVTZ levels. The ground and the first excited states of HBeN^? are predicted to be X²Π and A²Σ⁺ states, respectively. It was predicted that the ground state of HNBe^? is X²Σ⁺ state. The A²Π state of HNBe^? has unique imaginary frequency. A bend local minimum M1 was found along the 1²A″ potential energy surface and the A²Π state of HNBe^? should be the transition state of the isomerization reactions for M1 ? M1. The CASPT2/ANO potential energy curves of isomerization reactions were calculated as a function of HBeN bond angle. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010     

Darstellung von Dithiatetrazocinen und Folgereaktionen

Preparation of Dithiatetrazocine and Secondary Reactions Li[PhCN₂(SiMe₃)₂] ( 1 ) or PhCN₂(SiMe₃)₃ ( 3 ) react with SCl₂ to give in good yields the dithiatetrazocine PhC(NSN)₂CPh ( 2 ). By analogy, p-MeC₆H₄C(NSN)₂CC₆H₄Me-p ( 7 ), p-NO₂C₆H₄C(NSN)₂-CC₆H₄NO₂-p ( 8 ), and p-CF₃C₆H₄C(NSN)₂CC₆H₄CF₃-p ( 9 ) are obtained from the reaction of p-MeC₆H₄CN₂(SiMe₃)₃ ( 4 ), Li[p-NO₂-C₆H₄CN₂(SiMe₃)₂] ( 5 ), und Li[p-CF₃C₆H₄CN₂(SiMe₃)₂] ( 6 ) with SCl₂. Reaction of 2 /LiCl with AgAsF₆ in liquid SO₂ leads to [PhCN₂S₂]⁺[AsF₆]⁻ ( 10 ) and 3[PhCN₂S₂]⁺2[AsF₆]⁻Cl⁻ ( 11 ). The structures of 10 and 11 are confirmed by X-ray analyses.     

Kinetics and Mechanism of the Cerium(IV) Oxidation of Arnold's Base and the Protonation and Hydroxylation of Michler's Hydrol Blue

In aqueous H₂SO₄, Ce(IV) ion oxidizes rapidly Arnold's base((p-Me₂NC₆H₄)₂CH₂, Ar₂CH₂) to the protonated species of Michler's hydrol((p-Me₂NC₆H₄)₂CHOH, Ar₂CHOH) and Michler's hydrol blue((p-Me₂NC₆H₄)₂CH⁺, Ar₂CH⁺). With Ar₂CH₂ in excess, the rate law of the Ce(IV)-Ar₂CH₂ reaction in 0.100 M H₂SO₄ is expressed -d[Ce(IV)]/dt = k_app[Ar₂CH₂]₀[Ce(IV)] with k_app = 199 ± 8M^?1s^?1 at25°C. When the consumption of Ce(IV) ion is nearly complete, the characteristic blue color of Ar₂CH⁺ ion starts to appear; later it fades relatively slowly. The electron transfer of this reaction takes place on the nitrogen atom rather than on the methylene carbon atom. The dissociation of the binuclear complex [Ce(III)ArCHAr-Ce(III)] is responsible for the appearance of the Ar₂CH⁺ dye whereas the protonation reaction causes the dye to fade. In highly acidic solution, the rate law of the protonation reaction of Michler's hydrol blue is -d[Ar₂CH⁺]/dt = k_obs[Ar₂CH⁺] where K_obs = ((ac + 1)[H*] + bc[H⁺]²)/(a + b[H⁺]) (in HClO₄) and k_obs= ((ac + 1 + e[HSO₄^?])[H⁺] + bc[H⁺]² + d[HSO₄^?] + q[HSO₄^?]²/[H⁺])/(a + b[H⁺] + f[HSO₄^?] + g[HSO₄^?]/[H⁺]) (in H₂SO₄), and at 25°C and μ = 0.1 M, a = 0.0870 M s, b = 0.655 s, c = 0.202 M^?1s^?1, d = 0.110, e = 0.0070 M^?1, f = 0.156 s, g = 0.156 s, and q = 0.124. In highly basic solution, the rate law of the hydroxylation reaction of Michler's hydrol blue is -d[Ar₂CH⁺]/dt = k_OH[OH^?]₀[Ar₂CH⁺] with k_OH = 174 ± 1 M^?1s^?1 at 25°C and μ = 0.1 M. The protonation reaction of Michler's hydrol blue takes place predominantly via hydrolysis whereas its hydroxylation occurs predominantly via the path of direct OH attack.     

Dioxygen Reactivity of Biomimetic Iron–Catecholate and Iron–o‐Aminophenolate Complexes of a Tris(2‐pyridylthio)methanido Ligand: Aromatic C?C Bond Cleavage of Catecholate versus o‐Iminobenzosemiquinonate Radical Formation

An iron(III)–catecholate complex [L¹Fe^III(DBC)] ( 2 ) and an iron(II)–o‐aminophenolate complex [L¹Fe^II(HAP)] ( 3 ; where L¹=tris(2‐pyridylthio)methanido anion, DBC=dianionic 3,5‐di‐tert‐butylcatecholate, and HAP=monoanionic 4,6‐di‐tert‐butyl‐2‐aminophenolate) have been synthesised from an iron(II)–acetonitrile complex [L¹Fe^II(CH₃CN)₂](ClO₄) ( 1 ). Complex 2 reacts with dioxygen to oxidatively cleave the aromatic C? C bond of DBC giving rise to selective extradiol cleavage products. Controlled chemical or electrochemical oxidation of 2 , on the other hand, forms an iron(III)–semiquinone radical complex [L¹Fe^III(SQ)](PF₆) ( 2^ox‐PF₆ ; SQ=3,5‐di‐tert‐butylsemiquinonate). The iron(II)–o‐aminophenolate complex ( 3 ) reacts with dioxygen to afford an iron(III)–o‐iminosemiquinonato radical complex [L¹Fe^III(ISQ)](ClO₄) ( 3^ox‐ClO₄ ; ISQ=4,6‐di‐tert‐butyl‐o‐iminobenzosemiquinonato radical) via an iron(III)–o‐amidophenolate intermediate species. Structural characterisations of 1 , 2 , 2^ox and 3^ox reveal the presence of a strong iron? carbon bonding interaction in all the complexes. The bond parameters of 2^ox and 3^ox clearly establish the radical nature of catecholate‐ and o‐aminophenolate‐derived ligand, respectively. The effect of iron? carbon bonding interaction on the dioxygen reactivity of biomimetic iron–catecholate and iron–o‐aminophenolate complexes is discussed.     

The two-electron integral transformation and two-body density matrix transformation

Ann ⁵ algorithm for the transformation of quantum-mechanical four centre functions is presented in a form best suited for computers having a virtual memory capability. Part of the work to be submitted for the degree of Ph. D. in the University of Newcastle-upon-Tyne.     

Structural stability and evolution of terbium-doped silicon clusters and influence of 4f → 5d electronic transition mechanism on magnetism and appearance of photoelectron spectroscopy for TbSin0/− (n = 6-18) clusters

The global minimal structures of terbium-doped Si clusters and their anions TbSi _n^0/− (n = 6-18) are confirmed by employing the ABCluster unbiased global search technique combined with a B2PLYP double-hybrid density functional and comparing consistency of simulated and experimental photoelectron spectroscopy (PES). The results demonstrated that structural evolution patterns for neutral clusters prefer Tb-substitutional to Tb-encapsulated configuration starting from n = 16. While for the corresponding anionic clusters, the growth pattern adopts Tb-linked structures to encapsulated motif. The Natural Population Analysis revealed that the 4f electrons of Tb atom in TbSi _n^0/− (n = 6-18) clusters participate in bonding. The way to participate in bonding is one 4f electron transition to 5d orbital ([Xe]6s²4f⁹ → [Xe]6s²4f⁸5d¹), which significantly affects the cluster's magnetism and appearance of PES. The total magnetic moments of neutral TbSi _n and the corresponding anions maintain at 7 μB and 6 μB, respectively, which are larger than that of an isolated Tb atom. The HOMO-LUMO energy gap, relative stability, and chemical bonding analysis demonstrated that superatomic TbSi₁₆⁻ cluster is a magic cluster with fine thermodynamic and moderate chemical stability.     

On the Gas‐Phase Reactivity of Complexed OH+ with Halogenated Alkanes

OH⁺ is an extraordinarily strong oxidant. Complexed forms (L? OH⁺), such as H₂OOH⁺, H₃NOH⁺, or iron–porphyrin‐OH⁺ are the anticipated oxidants in many chemical reactions. While these molecules are typically not stable in solution, their isolation can be achieved in the gas phase. We report a systematic survey of the influence on L on the reactivity of L? OH⁺ towards alkanes and halogenated alkanes, showing the tremendous influence of L on the reactivity of L? OH⁺. With the help of with quantum chemical calculations, detailed mechanistic insights on these very general reactions are gained. The gas‐phase pseudo‐first‐order reaction rates of H₂OOH⁺, H₃NOH⁺, and protonated 4‐picoline‐N‐oxide towards isobutane and different halogenated alkanes C_nH_2n+1Cl (n=1–4), HCF₃, CF₄, and CF₂Cl₂ have been determined by means of Fourier transform ion cyclotron resonance meaurements. Reaction rates for H₂OOH⁺ are generally fast (7.2×10^?10–3.0×10^?9 cm³ mol^?1 s^?1) and only in the cases HCF₃ and CF₄ no reactivity is observed. In contrast to this H₃NOH⁺ only reacts with tC₄H₉Cl (k_obs=9.2×10^?10), while 4‐CH₃‐C₅H₄N‐OH⁺ is completely unreactive. While H₂OOH⁺ oxidizes alkanes by an initial hydride abstraction upon formation of a carbocation, it reacts with halogenated alkanes at the chlorine atom. Two mechanistic scenarios, namely oxidation at the halogen atom or proton transfer are found. Accurate proton affinities for HOOH, NH₂OH, a series of alkanes C_nH_2n+2 (n=1–4), and halogenated alkanes C_nH_2n+1Cl (n=1–4), HCF₃, CF₄, and CF₂Cl₂, were calculated by using the G3 method and are in excellent agreement with experimental values, where available. The G3 enthalpies of reaction are also consistent with the observed products. The tendency for oxidation of alkanes by hydride abstraction is expressed in terms of G3 hydride affinities of the corresponding cationic products C_nH_2n+1⁺ (n=1–4) and C_nH_2nCl⁺ (n=1–4). The hypersurface for the reaction of H₂OOH⁺ with CH₃Cl and C₂H₅Cl was calculated at the B3 LYP, MP2, and G3_m* level, underlining the three mechanistic scenarios in which the reaction is either induced by oxidation at the hydrogen or the halogen atom, or by proton transfer.