Probing Methanol Cluster Growth by Vacuum Ultraviolet Ionization
... through a bubbler containing 99.9% pure methanol and expanded through a 100 μm nozzle to a differentially pumped chamber which is kept at a pressure of 2 × 10−4 Torr during the expansion. The molecular beam is intersected with the VUV radiation at various axial distances from the nozzle (x = 2−25 mm) ...
... through a bubbler containing 99.9% pure methanol and expanded through a 100 μm nozzle to a differentially pumped chamber which is kept at a pressure of 2 × 10−4 Torr during the expansion. The molecular beam is intersected with the VUV radiation at various axial distances from the nozzle (x = 2−25 mm) ...
Learning Guide for Chapter 5 - NMR Spectroscopy
... What happens on a spectrum when two H's are equivalent? (draw two peaks on top of each other, both part of the same peak, gets more area then show the integration getting larger) Draw in all H's for the following compounds. Circle those that are equivalent, and then count the number of sets. show ho ...
... What happens on a spectrum when two H's are equivalent? (draw two peaks on top of each other, both part of the same peak, gets more area then show the integration getting larger) Draw in all H's for the following compounds. Circle those that are equivalent, and then count the number of sets. show ho ...
Boron and Metal Catalyzed CC and CH Bond Formation
... There are many people who deserve to be acknowledged for their effort, support and influence in helping me to pursue a Ph.D. in chemistry. First, I would like to express my sincerest appreciation to my advisor Dr. George Kabalka, for his guidance, patience, and financial support throughout my gradua ...
... There are many people who deserve to be acknowledged for their effort, support and influence in helping me to pursue a Ph.D. in chemistry. First, I would like to express my sincerest appreciation to my advisor Dr. George Kabalka, for his guidance, patience, and financial support throughout my gradua ...
A high-field solid-state Cl NMR and quantum chemical
... of NMR data.17,18,20–24,26 Both chlorine-35 (NA = 75.53%) and chlorine-37 (NA = 24.47%) are quadrupolar isotopes with nuclear spins of 3/2 and have significant quadrupole moments of 81.65 mb and 64.35 mb, respectively.27 Until the mid-nineties, chlorine SSNMR studies had been limited by these less ...
... of NMR data.17,18,20–24,26 Both chlorine-35 (NA = 75.53%) and chlorine-37 (NA = 24.47%) are quadrupolar isotopes with nuclear spins of 3/2 and have significant quadrupole moments of 81.65 mb and 64.35 mb, respectively.27 Until the mid-nineties, chlorine SSNMR studies had been limited by these less ...
Structural principles for minerals and inorganic
... Several minerals and inorganic compounds contain (XA4) tetrahedra, with anions, X (O2–, N3–, and F–), as central atoms and cations, A (Cu2+, Zn2+, Pb2+, Bi3+, REE3+, etc.), as ligands. These tetrahedra are well defined in these crystal structures because the bond valences between A and X are essenti ...
... Several minerals and inorganic compounds contain (XA4) tetrahedra, with anions, X (O2–, N3–, and F–), as central atoms and cations, A (Cu2+, Zn2+, Pb2+, Bi3+, REE3+, etc.), as ligands. These tetrahedra are well defined in these crystal structures because the bond valences between A and X are essenti ...
Synthetic Strategies for the Construction of Enantiomeric
... dimethyl maleate 4 proceeded reliably as reported by Trost9 in good yield (89%) to give the diester as a mixture of cis and predominantly trans isomers 5. Saponification of 5, either as a mixture of cis and trans isomers, or as the chromatographically purified trans isomer, gave a crystalline trans- ...
... dimethyl maleate 4 proceeded reliably as reported by Trost9 in good yield (89%) to give the diester as a mixture of cis and predominantly trans isomers 5. Saponification of 5, either as a mixture of cis and trans isomers, or as the chromatographically purified trans isomer, gave a crystalline trans- ...
Chapter 4 Alcohols and Alkyl Halides
... With respect to the halogen in a group of alkyl halides, the boiling point increases as one descends the periodic table; alkyl fluorides have the lowest boiling points, alkyl iodides the highest. This trend matches the order of increasing polarizability of the halogens. Polarizability is the ease wi ...
... With respect to the halogen in a group of alkyl halides, the boiling point increases as one descends the periodic table; alkyl fluorides have the lowest boiling points, alkyl iodides the highest. This trend matches the order of increasing polarizability of the halogens. Polarizability is the ease wi ...
Synthesis of Nitrogen-, Oxygen- and Sulphur
... after hydrolysis under mild conditions gave the target compound 2a in 35% yield. With this protocol in hand, we examined the scope and limitations of this method using a series of alkylcarbamate reactants (5b-5e). The results indicated that the reaction is effective for a range of aliphatic and arom ...
... after hydrolysis under mild conditions gave the target compound 2a in 35% yield. With this protocol in hand, we examined the scope and limitations of this method using a series of alkylcarbamate reactants (5b-5e). The results indicated that the reaction is effective for a range of aliphatic and arom ...
Structure and Sodium Ion Dynamics in Sodium
... similar approach used previously on Na2O·2SiO2 glass around 635− 699 °C.23 Spin−lattice relaxation times T1ρ in the rotating frame were obtained under static condition with a spin lock sequence at frequencies of ν1(23Na) ≈ 20 and 35 kHz on the 4 mm HX MAS high temperature NMR probe and at ≈ 6.7 and ...
... similar approach used previously on Na2O·2SiO2 glass around 635− 699 °C.23 Spin−lattice relaxation times T1ρ in the rotating frame were obtained under static condition with a spin lock sequence at frequencies of ν1(23Na) ≈ 20 and 35 kHz on the 4 mm HX MAS high temperature NMR probe and at ≈ 6.7 and ...
Sample chapter - Pharmaceutical Press
... repulsion in the same way as electrons in atomic orbitals. Each sp3 hybrid orbital will be occupied singly before spin pairing if necessary (Figure 1.9). The four sp3 hybrid orbitals adopt a tetrahedral geometry to minimise electron–electron repulsion between the hybrid orbitals (Figure 1.10). Each ...
... repulsion in the same way as electrons in atomic orbitals. Each sp3 hybrid orbital will be occupied singly before spin pairing if necessary (Figure 1.9). The four sp3 hybrid orbitals adopt a tetrahedral geometry to minimise electron–electron repulsion between the hybrid orbitals (Figure 1.10). Each ...
Theory of Ion Exchange
... (eqn [16]), the rate of exchange increases (t1/2 decreases) as the particle radius decreases, being proportional to 1/r20. For Rlm diffusion (eqn [17]), the rate increases less strongly as r0 is decreased (the proportionality is to 1/r0). In Rlm diffusion the exchange rate can also be increased by i ...
... (eqn [16]), the rate of exchange increases (t1/2 decreases) as the particle radius decreases, being proportional to 1/r20. For Rlm diffusion (eqn [17]), the rate increases less strongly as r0 is decreased (the proportionality is to 1/r0). In Rlm diffusion the exchange rate can also be increased by i ...
communication - Kyushu University Library
... near hydroxy group of the ammonium cation. Furthermore, it was reported that BH4– anion of the N-9-anthracenylmethyl cinchonidinium tetrahydroborate salt prefers to be located near the 9-hydroxy group in the literature.[14] These facts suggest that OH– is located near the 9-hydroxy group of the ammo ...
... near hydroxy group of the ammonium cation. Furthermore, it was reported that BH4– anion of the N-9-anthracenylmethyl cinchonidinium tetrahydroborate salt prefers to be located near the 9-hydroxy group in the literature.[14] These facts suggest that OH– is located near the 9-hydroxy group of the ammo ...
Organic Chemistry Fifth Edition
... If two succeeding states (such as a transition state and an unstable intermediate) are similar in energy, they are similar in structure. Hammond's postulate permits us to infer the structure of something we can't study (transition state) from something we can study (reactive intermediate). ...
... If two succeeding states (such as a transition state and an unstable intermediate) are similar in energy, they are similar in structure. Hammond's postulate permits us to infer the structure of something we can't study (transition state) from something we can study (reactive intermediate). ...
PDF - ACS Publications - American Chemical Society
... deep blue color of such solutions.22,23 However, cleavage in DOL/DME is not favored at room temperature, and hence the concentration of the trisulfide radical is neglible.24,25 Despite these many experimental studies to elucidate polysulfide speciation, very limited modeling work on Li−S batteries has ...
... deep blue color of such solutions.22,23 However, cleavage in DOL/DME is not favored at room temperature, and hence the concentration of the trisulfide radical is neglible.24,25 Despite these many experimental studies to elucidate polysulfide speciation, very limited modeling work on Li−S batteries has ...
4.7 Preparation of Alkyl Halides from Alcohols and Hydrogen
... The key intermediate in reaction of secondary and tertiary alcohols with hydrogen halides is a carbocation. A carbocation is a cation in which carbon has 6 valence electrons and a positive charge. ...
... The key intermediate in reaction of secondary and tertiary alcohols with hydrogen halides is a carbocation. A carbocation is a cation in which carbon has 6 valence electrons and a positive charge. ...
Substitution Reactions of Specifically Ortho
... conversion is n o t as effective. In t h e particular case of 2-allylpiperonal (Xi),t h e reaction (condition B) is only 11%complete. When t h e ortho-lithiated imines were treated with CuIs at -78 "C, a green suspension was formed which showed a more pronounced effect o n the allyl bromide alkylati ...
... conversion is n o t as effective. In t h e particular case of 2-allylpiperonal (Xi),t h e reaction (condition B) is only 11%complete. When t h e ortho-lithiated imines were treated with CuIs at -78 "C, a green suspension was formed which showed a more pronounced effect o n the allyl bromide alkylati ...
Modulated 2:1 layer silicates: Review, systematics, and
... minerals. These features usually include a layer com- outlined by Pauling was firmly establishedby later workprised of two types of sheets;octahedrally coordinated ers. However, Zussman (1954) found that such a model cations form a sheetby sharing edges,and tetrahedrally does not hold in all cases.F ...
... minerals. These features usually include a layer com- outlined by Pauling was firmly establishedby later workprised of two types of sheets;octahedrally coordinated ers. However, Zussman (1954) found that such a model cations form a sheetby sharing edges,and tetrahedrally does not hold in all cases.F ...
The Proline Effect Revisited - Department of Chemistry, York University
... (RRKM) calculations on protonated glycylglycylglycine.60,61 The barrier to formation of the b2 ion was found to 26.4 kcal mol-1, considerably lower than that for the formation of the y1 via a mechanism involving formation of diketopiperazine as the neutral N-terminal product (barrier 37.1 kcal mol-1 ...
... (RRKM) calculations on protonated glycylglycylglycine.60,61 The barrier to formation of the b2 ion was found to 26.4 kcal mol-1, considerably lower than that for the formation of the y1 via a mechanism involving formation of diketopiperazine as the neutral N-terminal product (barrier 37.1 kcal mol-1 ...
The Effects of Ozone on Compounds in Epicuticular Waxes in Plant
... the natural ageing of the waxes found on the surface of the needle.15 It is important to note that these studies did not examine the specific chemistry that was occurring in these epicuticular waxes which would provide an explanation for the observed changes. 1.4 Ozonolysis of Various Functional Gro ...
... the natural ageing of the waxes found on the surface of the needle.15 It is important to note that these studies did not examine the specific chemistry that was occurring in these epicuticular waxes which would provide an explanation for the observed changes. 1.4 Ozonolysis of Various Functional Gro ...
Recent Developments in Solid-State NMR Spectroscopy of
... (usually termed δiso) to the atomic-scale environment is able to provide a range of simple ...
... (usually termed δiso) to the atomic-scale environment is able to provide a range of simple ...
Cyclo-P3 Complexes of Vanadium: Redox
... coupling pattern is rather complicated (Figure 1). If the unpaired electron was coupled only to one 51V nucleus, then a simple eight-line pattern of the EPR signal would result (Robin−Day class I mixed-valence system). If it was completely delocalized over both 51V nuclei, then the signal would be s ...
... coupling pattern is rather complicated (Figure 1). If the unpaired electron was coupled only to one 51V nucleus, then a simple eight-line pattern of the EPR signal would result (Robin−Day class I mixed-valence system). If it was completely delocalized over both 51V nuclei, then the signal would be s ...
Catalytic, Enantioselective Alkylations of N,O- and
... Mechanism. To our surprise, the use of one equiv enol silane 4a with N,O-acetal l a did not lead to product 5a with 5 mol% 2; however, when two equiv were used, product 5a was formed in good yield. Although silyl ketene acetals can be quenched through silyl transfer reactions with alcohols, enol sil ...
... Mechanism. To our surprise, the use of one equiv enol silane 4a with N,O-acetal l a did not lead to product 5a with 5 mol% 2; however, when two equiv were used, product 5a was formed in good yield. Although silyl ketene acetals can be quenched through silyl transfer reactions with alcohols, enol sil ...
Selective Gas-Phase Cleavage at the Peptide
... completion of the Human Genome Project,11 MS/MS studies of peptides/proteins based on correlation analysis using DNA/ protein databases could become even more powerful tools in the future. Note that existing algorithms have already taken advantage of the knowledge regarding peptide fragmentation gai ...
... completion of the Human Genome Project,11 MS/MS studies of peptides/proteins based on correlation analysis using DNA/ protein databases could become even more powerful tools in the future. Note that existing algorithms have already taken advantage of the knowledge regarding peptide fragmentation gai ...
structure and thermodynamics of lanthanide
... Karraker in which he compared the spectra of solids and solutions13. He found that the spectra of Nd(Iii) in dilute solutions and in crystalline Nd(Br03)3 . 9HO were very similar. From this he concluded that the coordination number of aquo-Nd(In) is nine. As the concentration of the solutions increa ...
... Karraker in which he compared the spectra of solids and solutions13. He found that the spectra of Nd(Iii) in dilute solutions and in crystalline Nd(Br03)3 . 9HO were very similar. From this he concluded that the coordination number of aquo-Nd(In) is nine. As the concentration of the solutions increa ...
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.