Alkenes 4 - ChemWeb (UCC)
... Long before anything was known about the mechanism of this reaction it was recognised that 'Addition of HX to an alkene will proceed in such a way as to attach hydrogen to the least substituted carbon and X to the most substituted carbon'. This is known as Markovnikov's Rule after the Russian chemis ...
... Long before anything was known about the mechanism of this reaction it was recognised that 'Addition of HX to an alkene will proceed in such a way as to attach hydrogen to the least substituted carbon and X to the most substituted carbon'. This is known as Markovnikov's Rule after the Russian chemis ...
Chapter 5 | Molecular Orbitals
... separate regions with opposite signs of the wave function. When two orbitals overlap, and the overlapping regions have the same sign, the sum of the two orbitals has an increased electron probability in the overlap region. When two regions of opposite sign overlap, the combination has a decreased el ...
... separate regions with opposite signs of the wave function. When two orbitals overlap, and the overlapping regions have the same sign, the sum of the two orbitals has an increased electron probability in the overlap region. When two regions of opposite sign overlap, the combination has a decreased el ...
Anexo I. Modelos teóricos de análisis de sistemas de valencia mixta.
... 1.1. Modelo de Robin y Day. El modelo de Robin y Day constituye sólo una primera aproximación. Según este modelo, la existencia de acoplamiento electrónico entre los dos centros redox tiene como consecuencia la aparición de dos nuevos estados, con energías W1 y W2, cuya separación es función de la m ...
... 1.1. Modelo de Robin y Day. El modelo de Robin y Day constituye sólo una primera aproximación. Según este modelo, la existencia de acoplamiento electrónico entre los dos centros redox tiene como consecuencia la aparición de dos nuevos estados, con energías W1 y W2, cuya separación es función de la m ...
Joanna Kulesza
... Je tiens à exprimer ici la mémoire de mes anciennes amies: Anna Bresińska, Dominika Kozłowska, Anna Budzisz et Justyna Piotrowska. ...
... Je tiens à exprimer ici la mémoire de mes anciennes amies: Anna Bresińska, Dominika Kozłowska, Anna Budzisz et Justyna Piotrowska. ...
Investigation of the steric and electronic properties of 3
... of an alkyne may make it seem to be less likely to interact with the electron rich nitrogen moiety during hydroamination than the sp2 hybridized carbon of an alkene, but this is clearly not the case. The negative change in enthalpy (ΔH) is the thermodynamic driving force in all intermolecular hydroa ...
... of an alkyne may make it seem to be less likely to interact with the electron rich nitrogen moiety during hydroamination than the sp2 hybridized carbon of an alkene, but this is clearly not the case. The negative change in enthalpy (ΔH) is the thermodynamic driving force in all intermolecular hydroa ...
Section 2 Simple Molecular Orbital Theory
... two of the four hybrids are directed away from all other valence orbitals and hence can not form bonds. In all such qualitative mo analyses, the final results (i.e., how many mos there are of any given symmetry) will not depend on whether one thinks of the interactions involving atomic or hybrid orb ...
... two of the four hybrids are directed away from all other valence orbitals and hence can not form bonds. In all such qualitative mo analyses, the final results (i.e., how many mos there are of any given symmetry) will not depend on whether one thinks of the interactions involving atomic or hybrid orb ...
Introduction
... Treatment of [M(BH4)3(THF)3] with NEt3HBPh4 in THF afforded the cationic complexes [M(BH4)2(THF)5][BPh4] [M = U (1), Nd (2), Ce (3)] which were transformed into [M(BH4)2(18-crown-6)][BPh4] [M = U (4), Nd (5), Ce (6)] in the presence of 18-crown-6; [U(BH4)2(18-thiacrown-6)][BPh4] (7) was obtained fro ...
... Treatment of [M(BH4)3(THF)3] with NEt3HBPh4 in THF afforded the cationic complexes [M(BH4)2(THF)5][BPh4] [M = U (1), Nd (2), Ce (3)] which were transformed into [M(BH4)2(18-crown-6)][BPh4] [M = U (4), Nd (5), Ce (6)] in the presence of 18-crown-6; [U(BH4)2(18-thiacrown-6)][BPh4] (7) was obtained fro ...
Proofs to - Research Explorer
... metal to carbene carbon distance as the acceptor character of the carbene ligand is reduced. The data in Table 1 permit a direct experimental confirmation of these investigations. The alkylidene complex [Fe{=C(H)Me}(dppe)Cp*][PF6] exhibits a short Fe-Cα distance (1.787(8) Å), similar to that reporte ...
... metal to carbene carbon distance as the acceptor character of the carbene ligand is reduced. The data in Table 1 permit a direct experimental confirmation of these investigations. The alkylidene complex [Fe{=C(H)Me}(dppe)Cp*][PF6] exhibits a short Fe-Cα distance (1.787(8) Å), similar to that reporte ...
Alkenes
... reaction yields the more highly substituted alkene as the major product. The more stable alkene product predominates. ...
... reaction yields the more highly substituted alkene as the major product. The more stable alkene product predominates. ...
Lorell Thesis Final Version in PDF S
... finished. To my husband, Tito, who has given me the happiest days of my life and stood beside me in all the happy and stressful moments. To my daughter Lorelys Maia, she is my whole life and is always inspiring me how to be a better person overall. To my parents José and Betzaida, who always support ...
... finished. To my husband, Tito, who has given me the happiest days of my life and stood beside me in all the happy and stressful moments. To my daughter Lorelys Maia, she is my whole life and is always inspiring me how to be a better person overall. To my parents José and Betzaida, who always support ...
Chem E2b - Organic Chemistry II What is Organic Chemistry?
... As with acidity, inductive effects are generally WEAKER than resonance effects Z = NR2, OR: Strongly Activating (resonance) Z = NHCO2R, OCO2R: Moderately Activating (inductive) Z = R (Alkyl, vinyl): Weakly Activating (inductive) Y = F, Cl, Br, I: Weakly Deactivating (inductive withdrawal/resonance d ...
... As with acidity, inductive effects are generally WEAKER than resonance effects Z = NR2, OR: Strongly Activating (resonance) Z = NHCO2R, OCO2R: Moderately Activating (inductive) Z = R (Alkyl, vinyl): Weakly Activating (inductive) Y = F, Cl, Br, I: Weakly Deactivating (inductive withdrawal/resonance d ...
The Impact of Ligand Design on the Coordination Chemistry and
... [XZY] where Z is the central, anchoring Lewis donor while X and Y are flanking Lewis donors. Ever since initial reports of transition metal pincer complexes were published in the late 1970’s, there has been burgeoning interest in such complexes because of their desirable robust nature, generally sim ...
... [XZY] where Z is the central, anchoring Lewis donor while X and Y are flanking Lewis donors. Ever since initial reports of transition metal pincer complexes were published in the late 1970’s, there has been burgeoning interest in such complexes because of their desirable robust nature, generally sim ...
Density Functional Study of Molecular Orbitals of Ferrocene and
... provides qualitative results at a lower cost than abinitio methods with a comparable accuracy. By using these methods, we have optimized the energy, eigenvalues, eigenvector, population analysis, HOMOLUMO energy gap, hardness, softness, electronegativity, visualize the HOMO and LUMO orbitals of ferr ...
... provides qualitative results at a lower cost than abinitio methods with a comparable accuracy. By using these methods, we have optimized the energy, eigenvalues, eigenvector, population analysis, HOMOLUMO energy gap, hardness, softness, electronegativity, visualize the HOMO and LUMO orbitals of ferr ...
a bond-valence approach to the structure, chemistry and
... emanate from the structural unit. Some of these hydrogen bonds may link to anions of the adjacent (or even the same) structural unit, but the hydrogen bonds that do not (most of them) must link to (H2O) groups of the interstitial complex. This indicates that these (OH) groups of the structural unit ...
... emanate from the structural unit. Some of these hydrogen bonds may link to anions of the adjacent (or even the same) structural unit, but the hydrogen bonds that do not (most of them) must link to (H2O) groups of the interstitial complex. This indicates that these (OH) groups of the structural unit ...
Molecular Structure and Orbitals - Blackboard
... Molecular Orbital Theory • The valence bond model is easy to visualize, and works well for most molecules, but it does not describe magnetic and spectral properties well. A more complex model must be used to explain these phenomena. • In Molecular Orbital (MO) theory, electrons occupy molecular orbi ...
... Molecular Orbital Theory • The valence bond model is easy to visualize, and works well for most molecules, but it does not describe magnetic and spectral properties well. A more complex model must be used to explain these phenomena. • In Molecular Orbital (MO) theory, electrons occupy molecular orbi ...
Anionic rearrangement of 2-benzyloxypyridine derivatives and a synthetic approach to aldingenin B
... [1,2]-Anionic rearrangements are important tools for altering the complexity of molecules at hand. In Part I of this dissertation, an anionic rearrangement of 2-benzyloxypyridine is described. Pyridine-directed metallation of the benzylic carbon leads to 1,2-migration of pyridine via a postulated as ...
... [1,2]-Anionic rearrangements are important tools for altering the complexity of molecules at hand. In Part I of this dissertation, an anionic rearrangement of 2-benzyloxypyridine is described. Pyridine-directed metallation of the benzylic carbon leads to 1,2-migration of pyridine via a postulated as ...
isomeria geometrica
... • Different molecules (enantiomers) must have different names. • Usually only one enantiomer will be biologically active. • Configuration around the chiral carbon is specified with (R) and (S). ...
... • Different molecules (enantiomers) must have different names. • Usually only one enantiomer will be biologically active. • Configuration around the chiral carbon is specified with (R) and (S). ...
Vibrational signatures of Hydrogen bonding in the protonated
... quantum simulation12 which predicts this transition at 464 cm-1 and also has been the basis for the assignment of the 1⋅νz+1⋅νR combination band. In the present contribution our previous work on the protonated ammonia dimer12 is extended in several respects. IRMPD spectra of N2H7+ are presented down ...
... quantum simulation12 which predicts this transition at 464 cm-1 and also has been the basis for the assignment of the 1⋅νz+1⋅νR combination band. In the present contribution our previous work on the protonated ammonia dimer12 is extended in several respects. IRMPD spectra of N2H7+ are presented down ...
High-resolution molecular structure of a peptide
... tances in the 3–6 Å range in TTR(105–115) fibrils (Table 1 and Table 2, which is published as supporting information on the PNAS web site) were obtained by using the 3D ZF TEDOR technique (30), and representative results are shown in Fig. 1. Fig. 1 A shows a single 2D plane from the 3D ZF TEDOR data ...
... tances in the 3–6 Å range in TTR(105–115) fibrils (Table 1 and Table 2, which is published as supporting information on the PNAS web site) were obtained by using the 3D ZF TEDOR technique (30), and representative results are shown in Fig. 1. Fig. 1 A shows a single 2D plane from the 3D ZF TEDOR data ...
CHAPTER 5
... the double bond possesses a component and a component. The component results when an sp2 orbital of one carbon, oriented so that its axis lies along the internuclear axis, overlaps with a similarly disposed sp2 orbital of the other carbon. Each sp2 orbital contains one electron, and the result ...
... the double bond possesses a component and a component. The component results when an sp2 orbital of one carbon, oriented so that its axis lies along the internuclear axis, overlaps with a similarly disposed sp2 orbital of the other carbon. Each sp2 orbital contains one electron, and the result ...
Density Functional Study of Molecular Orbitals of
... 1. combination of Beck’s three-parameter exchange functional and Lee-Yang-Parr correlation functional with 6-31G 2. basis set. These methods are found in Gaussian 03W program. B3LYP is a DFT method with hybrid functional that provides qualitative results at a lower cost than abinitio methods with a ...
... 1. combination of Beck’s three-parameter exchange functional and Lee-Yang-Parr correlation functional with 6-31G 2. basis set. These methods are found in Gaussian 03W program. B3LYP is a DFT method with hybrid functional that provides qualitative results at a lower cost than abinitio methods with a ...
Solid-State 23Na Nuclear Magnetic Resonance of Sodium
... In general, solid-state 23Na NMR spectra of sodiumionophore complexes were obtained using MAS and high-power proton decoupling. Under such circumstances, the observed central-transition 23Na NMR spectra exhibit typical features arising from second-order quadrupole interaction. In most cases only a s ...
... In general, solid-state 23Na NMR spectra of sodiumionophore complexes were obtained using MAS and high-power proton decoupling. Under such circumstances, the observed central-transition 23Na NMR spectra exhibit typical features arising from second-order quadrupole interaction. In most cases only a s ...
CHAPTER 1—COVALENT BONDING AND
... 74. Which of the following statements is not true? a. The sp3C H bond of an alkane is weaker than the spC H bond of an alkyne. b. The carbon-carbon triple bond of an alkyne is shorter than the carboncarbon bond of alkenes. c. The carbon-carbon triple bond of an alkene is exactly three times as stron ...
... 74. Which of the following statements is not true? a. The sp3C H bond of an alkane is weaker than the spC H bond of an alkyne. b. The carbon-carbon triple bond of an alkyne is shorter than the carboncarbon bond of alkenes. c. The carbon-carbon triple bond of an alkene is exactly three times as stron ...
Improved Synthesis, Separation, Transition Metal Coordination and
... P{1H} spectra of meso-Ni2Cl4(et,ph-P4) with 1-hexene in acetone-d6/D2O recorded at 15°C (light blue), 10°C (dark blue), 25°C (black), 50°C (orange), 80°C (purple), and 100°C (red). For higher temperatures the NMR tube was tube pressurized to 90 psi with O2 ......................................... ...
... P{1H} spectra of meso-Ni2Cl4(et,ph-P4) with 1-hexene in acetone-d6/D2O recorded at 15°C (light blue), 10°C (dark blue), 25°C (black), 50°C (orange), 80°C (purple), and 100°C (red). For higher temperatures the NMR tube was tube pressurized to 90 psi with O2 ......................................... ...
2-Norbornyl cation
In organic chemistry, the term 2-norbornyl cation (equivalent with 2-bicyclo-[2.2.1]heptyl cation) describes one of the three carbocations formed from derivatives of norbornane. Though 1-norbornyl and 7-norbornyl cations have been studied, the most extensive studies and vigorous debates have been centered on the exact structure of the 2-norbornyl cation.The 2-norbornyl cation has been formed from a variety of norbornane derivatives and reagents. First reports of its formation and reactivity published by Saul Winstein sparked controversy over the nature of its bonding, as he invoked a three-center two-electron bond to explain the stereoselectivity of the resulting product. Herbert C. Brown challenged this assertion on the grounds that classical resonance structures could explain the stereospecificity without needing to adapt a new perspective of bonding.Evidence of the non-classical nature of the 2-norbornyl cation grew over the course of several decades, mainly through spectroscopic data gathered using methods such as Nuclear magnetic resonance (NMR). Crystallographic confirmation of its non-classical nature did not come until quite recently.The nature of bonding in the 2-norbornyl cation incorporated many new ideas into the field’s understanding of chemical bonds. Similarities can be seen between this cation and others, such as boranes.