1. Primary Non Contributory Endorsement Iso
2. Primary And Noncontributory Endorsement Example

Q: Lately, we have received several requests asking for proof that the umbrella includes “primary and noncontributory” provisions.Some additional insureds are now saying that even if the umbrella is considered to follow form, it does not include those provisions because they are an endorsement to, not part of, the underlying coverage form.That makes sense to me. Is it correct? Would an actual Primary and Noncontributory endorsement need to be added to the umbrella policy to comply with this requirement?Response 1: Normally, liability insurance flows horizontally before it goes vertically. By that, I mean the primary general liability insurance pays before excess—see also “other insurance” language.So, if you’re the additional insured on ABC’s GL policy and there is a claim, ABC’s GL policy pays. But before it goes to ABC’s umbrella to protect you, your own primary GL responds. Once that’s exhausted, ABC’s umbrella will respond.Key word here: “normally.” A few carriers now have umbrella endorsements that grant additional insured primary coverage, so the additional insured would not have to use their own GL.Response 2: There is no such endorsement. Umbrella policies are never primary—they’re excess over either underlying or a retained limit.Response 3: The policy has an “other insurance” condition, which you’d have to read to determine how it responds.

If you want it to respond differently, yes, the policy would have to be endorsed.Response 4: ISO has a noncontributory endorsement for this, though I don’t think it really does what it was designed to do. This issue comes up most frequently when someone uses a commercial general liability policy and an umbrella to meet minimum liability limit requirements.Say the insured has a $1-million CGL and a job that requires $2 million. They could up their CGL limit, or they could buy a $1-million excess policy that sits over both the CGL and the business auto policy. Or maybe both CGL and auto requirements are higher, warranting an umbrella than an increase in underlying limits.The issue is horizontal versus vertical exhaustion of limits. What’s the order of payment: insured’s CGL, then additional insured’s CGL, then insured’s excess, then additional insured’s excess? Or does it go insured’s CGL, then insured’s excess, then additional insured’s CGL, then additional insured’s excess? Needless to say, the additional insured wants the latter.Response 5: A few umbrella and excess liability insurers have built “primary and noncontributory” language into their forms, but the majority have not.

In the case of the latter, yes—you need a Primary and Noncontributory endorsement.Response 6: Yes, you need to have an endorsement added to the umbrella policy which includes the “primary and noncontributory” language.Response 8: By definition, I don’t believe an umbrella policy can be primary. It can be noncontributory if the proper endorsement is attached.Response 9: The umbrella will not be primary and noncontributory. The question is, will the additional insured status provided by the umbrella be primary and noncontributory?Response 10: It depends on the umbrella policy language. Typically, the umbrella requires a special endorsement to be primary and noncontributory, with the coverage carried by the additional insured named on the CGL with primary and noncontributory coverage.This question was originally submitted by an agent through the.

Answers to other coverage questions are available on the. If you need help accessing the website,.

Contents.Background The kinetic isotope effect is considered to be one of the most essential and sensitive tools for the study of, the knowledge of which allows the improvement of the desirable qualities of the corresponding reactions. For example, kinetic isotope effects can be used to reveal whether a reaction follows a (S N1) or (S N2) pathway.In the reaction of and (shown in the introduction), the observed methyl carbon kinetic isotope effect indicates an S N2 mechanism. Depending on the pathway, different strategies may be used to stabilize the of the of the reaction and improve the and selectivity, which are important for industrial applications.

Isotopic rate changes are most pronounced when the relative change is greatest, since the effect is related to vibrational frequencies of the affected bonds. For instance, changing a atom (H) to its isotope (D) represents a 100% increase in mass, whereas in replacing -12 with carbon-13, the mass increases by only 8 percent. The rate of a reaction involving a C–H bond is typically 6–10 times faster than the corresponding C–D bond, whereas a 12C reaction is only 4 percent faster than the corresponding 13C reaction: 445 (even though, in both cases, the isotope is one heavier).Isotopic substitution can modify the rate of reaction in a variety of ways. In many cases, the rate difference can be rationalized by noting that the mass of an atom affects the of the that it forms, even if the for the reaction is nearly identical. Heavier isotopes will lead to lower vibration frequencies, or, viewed, will have lower. With a lower zero-point energy, more energy must be supplied to break the bond, resulting in a higher for bond cleavage, which in turn lowers the measured rate (see, for example, the ).: 427 Classification Primary kinetic isotope effects A primary kinetic isotope effect may be found when a bond to the isotopically-labeled atom is being formed or broken.: 427 Depending on the way a kinetic isotope effect is probed (parallel measurement of rates vs.

Intermolecular competition vs. Intramolecular competition), the observation of a primary kinetic isotope effect is indicative of breaking/forming a bond to the isotope at the rate-limiting step, or subsequent product-determining step(s). (The misconception that a primary kinetic isotope effect must reflect bond cleavage/formation to the isotope at the rate-limiting step is frequently repeated in textbooks and the primary literature: see the section on below.)For the previously mentioned nucleophilic substitution reactions, primary kinetic isotope effects have been investigated for both the leaving groups, the nucleophiles, and the α-carbon at which the substitution occurs. Interpretation of the leaving group kinetic isotope effects had been difficult at first due to significant contributions from temperature independent factors. Kinetic isotope effects at the α-carbon can be used to develop some understanding into the symmetry of the transition state in S N2 reactions, although this kinetic isotope effect is less sensitive than what would be ideal, also due to contribution from non-vibrational factors.

Is a quantum mechanical effect tied to the laws of wave mechanics, not. Therefore, tunneling tends to become more important at low temperatures, where even the smallest kinetic energy barriers may not be overcome but can be tunneled through.Peter S. Reported rate constants for the ring expansion of 1-methylcyclobutylfluorocarbene to be 4.0 x 10 −6/s in nitrogen and 4.0 x 10 −5/s in argon at 8 kelvin. They calculated that at 8 kelvin, the reaction would proceed via a single quantum state of the reactant so that the reported rate constant is temperature independent and the tunneling contribution to the rate was 152 orders of magnitude greater than the contribution of passage over the transition state energy barrier.So despite the fact that conventional chemical reactions tend to slow down dramatically as the temperature is lowered, tunneling reactions rarely change at all. Particles that tunnel through an activation barrier are a direct result of the fact that the wave function of an intermediate species, reactant or product is not confined to the energy well of a particular trough along the energy surface of a reaction but can 'leak out' into the next energy minimum.

In light of this, tunneling should be temperature independent.For the hydrogen abstraction from gaseous n-alkanes and cycloalkanes by hydrogen atoms over the temperature range 363–463 K, the H/D kinetic isotope effect data were characterized by small ratios A H/ A D ranging from 0.43 to 0.54 and large activation energy differences from 9.0 to 9.7 kJ/mol. Basing their arguments on, the small A factor ratios associated with the large activation energy differences (usually about 4.5 kJ/mol for C–H(D) bonds) provided strong evidence for tunneling. For the purpose of this discussion, it is important is that the A factor ratio for the various paraffins they used was approximately constant throughout the temperature range.The observation that tunneling is not entirely temperature independent can be explained by the fact that not all molecules of a certain species occupy their vibrational ground state at varying temperatures. Adding thermal energy to a potential energy well could cause higher vibrational levels other than the ground state to become populated. For a conventional kinetically driven reaction, this excitation would only have a small influence on the rate. However, for a tunneling reaction, the difference between the and the first vibrational energy level could be huge. The tunneling correction term Q is linearly dependent on barrier width and this width is significantly diminished as the number on the increase.

The decrease of the barrier width can have such a huge impact on the tunneling rate that even a small population of excited vibrational states would dominate this process. In organic reactions, this proton tunneling effect has been observed in such reactions as the and iodination of with hindered base with a reported KIE of 25 at 25 °C:and in a although it is observed that it is difficult to extrapolate experimental values obtained at elevated temperatures to lower temperatures:It has long been speculated that high efficiency of enzyme catalysis in proton or hydride ion transfer reactions could be due partly to the quantum mechanical tunneling effect.

Environment at the active site of an enzyme positions the donor and acceptor atom close to the optimal tunneling distance, where the amino acid side chains can 'force' the donor and acceptor atom closer together by electrostatic and noncovalent interactions. It is also possible that the enzyme and its unusual hydrophobic environment inside a reaction site provides tunneling-promoting vibration. Studies on ketosteroid isomerase have provided experimental evidence that the enzyme actually enhances the coupled motion/hydrogen tunneling by comparing primary and secondary kinetic isotope effects of the reaction under enzyme catalyzed and non-enzyme catalyzed conditions.Many examples exist for proton tunneling in enzyme catalyzed reactions that were discovered by KIE. A well studied example is methylamine dehydrogenase, where large primary KIEs of 5–55 have been observed for the proton transfer step. In this experiment, the rate constants for the normal substrate and its isotopically labeled analogue are determined independently, and the KIE is obtained as a ratio of the two. The accuracy of the measured KIE is severely limited by the accuracy with which each of these rate constants can be measured. Furthermore, reproducing the exact conditions in the two parallel reactions can be very challenging.

Nevertheless, a measurement of a large kinetic isotope effect through direct comparison of rate constants is indicative that C-H bond cleavage occurs at the rate-determining step. (A smaller value could indicate an isotope effect due to a pre-equilibrium, so that the C-H bond cleavage occurs somewhere before the rate-determining step.)B) KIE determined from an intermolecular competition. In this type of experiment, the same substrates that are used in Experiment A are employed, but they are allowed in to react in the same container, instead of two separate containers. The kinetic isotope effect from this experiment is determined by the relative amount of products formed from C-H versus C-D functionalization (or it can be inferred from the relative amounts of unreacted starting materials).

It is necessary to quench the reaction before it goes to completion to observe the kinetic isotope effect (see the Evaluation section below). Generally, the reaction is halted at low conversion (5 to 10% conversion) or a large excess ( 5 equiv.) of the isotopic mixture is used. This experiment type ensures that both C-H and C-D bond functionalizations occur under exactly the same conditions, and the ratio of products from C-H and C-D bond functionalizations can be measured with much greater precision than the rate constants in Experiment A. Moreover, only a single measurement of product concentrations from a single sample is required. However, an observed kinetic isotope effect from this experiment is more difficult to interpret, since it may either mean that C-H bond cleavage occurs during the rate-determining step or at a product-determining step ensuing the rate-determining step. The absence of a kinetic isotope effect, at least according to Simmons and Hartwig, is nonetheless indicative of the C-H bond cleavage not occurring during the rate-determining step.C) KIE determined from an intramolecular competition. This type of experiment is analogous to Experiment B, except this time there is an intramolecular competition for the C-H or C-D bond functionalization.

In most cases, the substrate possesses a directing group (DG) between the C-H and C-D bonds. Calculation of the kinetic isotope effect from this experiment and its interpretation follow the same considerations as that of Experiment B. However, the results of Experiments B and C will differ if the irreversible binding of the isotope-containing substrate takes place in Experiment B prior to the cleavage of the C-H or C-D bond. In such a scenario, an isotope effect may be observed in Experiment C (where choice of the isotope can take place even after substrate binding) but not in Experiment B (since the choice of whether C-H or C-D bond cleaves is already made as soon as the substrate binds irreversibly). In contrast to Experiment B, the reaction does not need to be halted at low consumption of isotopic starting material to obtain an accurate k H/ k D, since the ratio of H and D in the starting material is 1:1, regardless of the extent of conversion.One non-C-H activation example of different isotope effects being observed in the case of intermolecular (Experiment B) and intramolecular (Experiment C) competition is the photolysis of diphenyldiazomethane in the presence of t-butylamine.

To explain this result, the formation of diphenylcarbene, followed by irreversible nucleophilic attack by t-butylamine was proposed. Because there is little isotopic difference in the rate of nucleophilic attack, the intermolecular experiment resulted in a KIE close to 1. In the intramolecular case, however, the product ratio is determined by the proton transfer that occurs after the nucleophilic attack, a process for which there is a substantial KIE of 2.6. Thus, Experiments A, B, and C will give results of differing levels of precision and require different experimental setup and ways of analyzing data. As a result, the feasibility of each type of experiment will depend on the kinetic and stoichiometric profile of the reaction, as well as the physical characteristics of the reaction mixture (e.g., homogeneous vs. Moreover, as noted in the paragraph above, the experiments provide kinetic isotope effect data for different steps of a multi-step reaction, depending on the relative locations of the rate-limiting step, product-determining steps, and/or C-H/D cleavage step.The hypothetical examples below illustrate common scenarios.

Consider the following reaction coordinate diagram. For a reaction with this profile, all three experiments (A, B, and C) will yield a significant primary kinetic isotope effect. Reaction energy profile for when C-H cleavage occurs at the RDSOn the other hand, if a reaction follows the following energy profile, in which the C-H or C-D bond cleavage is irreversible but occurs after the rate-determining step (RDS), no significant kinetic isotope effect will be observed with Experiment A, since the overall rate is not affected by the isotopic substitution.

Nevertheless, the irreversible C-H bond cleavage step will give a primary kinetic isotope effect with the other two experiments, since the second step would still affect the product distribution. Therefore, with Experiments B and C, it is possible to observe the kinetic isotope effect even if C-H or C-D bond cleavage occurs not in the rate-determining step, but in the product-determining step. A large part of the kinetic isotope effect arises from vibrational zero-point energy differences between the reactant ground state and the transition state that vary between the reactant and its isotopically substituted analogue. While it is possible to carry involved calculations of kinetic isotope effects using computational chemistry, much of the work done is of simpler order that involves the investigation of whether particular isotopic substitutions produce a detectable kinetic isotope effect or not. Vibrational changes from isotopic substitution at atoms away from the site where the reaction occurs tend to cancel between the reactant and the transition state. Therefore, the presence of a kinetic isotope effect indicates that the isotopically labeled atom is at or very near the reaction site.The absence of an isotope effect is more difficult to interpret: It may mean that the isotopically labeled atom is away from the reaction site, but it may also mean that there are certain compensating effects that lead to the lack of an observable kinetic isotope effect.

For example, the differences between the reactant and the transition state zero-point energies may be identical between the normal reactant and its isotopically labeled version. Alternatively, it may mean that the isotopic substitution is at the reaction site, but vibrational changes associated with bonds to this atom occur after the rate-determining step.

Such a case is illustrated in the following example, in which ABCD represents the atomic skeleton of a molecule. 13C KIEs for enantioselective intramolecular alkene cyanoamidation reaction (left no additive, right add BPh 3)The primary 13C kinetic isotope effect observed in the absence of BPh 3 suggests a reaction mechanism with rate limiting cis oxidation into the C–CN bond of the. The addition of BPh 3 causes a relative decrease in the observed 13C kinetic isotope effect which led Frost et al.

To suggest a change in the rate limiting step from cis oxidation to coordination of palladium to the cyanoformamide. DEPT-55 NMR Although kinetic isotope effect measurements at natural abundance are a powerful tool for understanding reaction mechanisms, the amounts of material required for analysis can make this technique inaccessible for reactions that employ expensive reagents or unstable starting materials. In order to mitigate these limitations, Jacobsen and coworkers developed 1H to 13C polarization transfer as a means to reduce the time and material required for kinetic isotope effect measurements at natural abundance. The (DEPT) takes advantage of the larger of 1H over 13C to theoretically improve measurement sensitivity by a factor of 4 or decrease experiment time by a factor of 16.

This method for natural abundance kinetic isotope measurement is favorable for analysis for reactions containing unstable starting materials, and catalysts or products that are relatively costly.Jacobsen and coworkers identified the thiourea-catalyzed glycosylation of galactose as a reaction that met both of the aforementioned criteria (expensive materials and unstable substrates) and was a reaction with a poorly understood mechanism. Glycosylation is a special case of nucleophilic substitution that lacks clear definition between S N1 and S N2 mechanistic character. The presence of the oxygen adjacent to the site of displacement (i.e., C1) can stabilize positive charge. This charge stabilization can cause any potential concerted pathway to become asynchronous and approaches intermediates with oxocarbenium character of the S N1 mechanism for glycosylation. Hatsune miku clock for desktop. 13C kinetic isotope effect measurements for thiourea catalyzed glycosylation of galactoseJacobsen and coworkers observed small normal KIE’s at C1, C2, and C5 which suggests significant oxocarbenium character in the transition state and an asynchronous reaction mechanism with a large degree of charge separation.Isotope-ratio mass spectrometry High precision (IRMS) is another method for measuring of for natural abundance KIE measurements.

Widlanski and coworkers demonstrated 34SKIE at natural abundance measurements for the of monoesters. Their observation of a large KIE suggests S-O bond cleavage is rate controlling and likely rules out an associate. 34S isotope effect on sulfate ester hydrolysis reactionThe major limitation for determining KIE’s at natural abundance using IRMS is the required site selective degradation without isotopic fractionation into an analyzable small molecule, a non-trivial task. Case studies Primary hydrogen isotope effects Primary hydrogen kinetic isotope effects refer to cases in which a bond to the isotopically labeled hydrogen is formed or broken at a rate- and/or product-determining step of a reaction.

These are the most commonly measured kinetic isotope effects, and much of the previously covered theory refers to primary kinetic isotope effects.When there is adequate evidence that transfer of the labeled hydrogen occurs in the rate-determining step of a reaction, if a fairly large kinetic isotope effect is observed, e.g. KH/kD of at least 5-6 or kH/kT about 10-13 at room temperature, it is quite likely that the hydrogen transfer is linear and that the hydrogen is fairly symmetrically located in the transition state. It is usually not possible to make comments about tunneling contributions to the observed isotope effect unless the effect is very large. If the primary kinetic isotope effect is not as large, it is generally considered to be indicative of a significant contribution from heavy-atom motion to the reaction coordinate, although it may also mean that hydrogen transfer follows a nonlinear pathway. Secondary hydrogen isotope effects The secondary hydrogen isotope effects or secondary kinetic isotope effect (SKIE) arises in cases where the isotopic substitution is remote from the bond being broken. The remote atom, nonetheless, influences the internal vibrations of the system that via changes in the zero point energy (ZPE) affect the rates of chemical reactions.

Such effects are expressed as ratios of rate for the light isotope to that of the heavy isotope and can be 'normal' (ratio is greater than or equal to 1) or 'inverse' (ratio is less than 1) effects. SKIE are defined as α,β (etc.) secondary isotope effects where such prefixes refer to the position of the isotopic substitution relative to the reaction center (see ). The prefix α refers to the isotope associated with the reaction center while the prefix β refers to the isotope associated with an atom neighboring the reaction center and so on.In physical organic chemistry, SKIE is discussed in terms of such as induction, bond hybridization,. These properties are determined by electron distribution, and depend upon vibrationally averaged bond length and angles that are not greatly affected by isotopic substitution.

Thus, the use of the term 'electronic isotope effect' while legitimate is discouraged from use as it can be misinterpreted to suggest that the isotope effect is electronic in nature rather than vibrational.SKIE's can be explained in terms of changes in orbital hybridization. When the hybridization of a carbon atom changes from sp 3 to sp 2, a number of vibrational modes (stretches, in-plane and out-of-plane bending) are affected. The in-plane and out-of-plane bending in an sp 3 hybridized carbon are similar in frequency due to the symmetry of an sp 3 hybridized carbon. Other examples Since kinetic isotope effects arise from differences in isotopic masses, the largest observable kinetic isotope effects are associated with isotopic substitutions of hydrogen with deuterium (100% increase in mass) or tritium (200% increase in mass). Kinetic isotope effects from isotopic mass ratios can be as large as 36.4 using muons.

Primary Non Contributory Endorsement Iso

They have produced the lightest hydrogen atom, 0.11H (0.113 amu), in which an electron orbits around a positive muon (μ +) 'nucleus' that has a mass of 206 electrons. They have also prepared the heaviest hydrogen atom analogue by replacing one electron in helium with a negative muon (μ −) to form Heμ with an atomic mass of 4.116 amu. Since the negative muon is much heavier than an electron, it orbits much closer to the nucleus, effectively shielding one proton, making Heμ to behave as 4.1H.

With these exotic species, the reaction of H with 1H 2 was investigated. Rate constants from reacting the lightest and the heaviest hydrogen analogues with 1H 2 were then used to calculate the k 0.11/ k 4.1 kinetic isotope effect, in which there is a 36.4 fold difference in isotopic masses.

For this reaction, isotopic substitution happens to produce an inverse kinetic isotope effect, and the authors report a kinetic isotope effect as low as 1.74 x 10 −4, which is the smallest kinetic isotope effect ever reported.The kinetic isotope effect leads to a specific distribution of deuterium isotopes in natural products, depending on the route they were synthesized in nature. By NMR spectroscopy, it is therefore easy to detect whether the alcohol in wine was fermented from, or from illicitly added.Another that was elucidated using the kinetic isotope effect is the of:In this particular 'intramolecular KIE' study, a benzylic hydrogen undergoes by bromine using as the brominating agent.

Primary And Noncontributory Endorsement Example

It was found that PhCH 3 brominates 4.86x faster than PhCD 3. A large KIE of 5.56 is associated with the reaction of with and.In this reaction the rate-limiting step is formation of the by deprotonation of the ketone. In this study the KIE is calculated from the for regular 2,4-dimethyl-3-pentanone and its deuterated isomer by measurements.In asymmetric catalysis, there are rare instances in which a kinetic isotope effect manifests as a significant difference in the enantioselectivity observed for a deuterated substrate compared to a non-deuterated one. One example was reported by Toste and coworkers, in which a deuterated substrate produced an enantioselectivity of 83% ee, compared to 93% ee for the undeuterated substrate. The effect was taken to corroborate additional inter- and intramolecular competition KIE data that suggested cleavage of the C-H/D bond in the enantiodetermining step.See also.References.