103 research outputs found
Recommended from our members
Exemptions for Firearms in Bankruptcy
This report is categorized into three categories: (I) Federal Exemption Under the U.S. Bankruptcy Code, (II) States' Exemption for Firearms and (III) Legislation Proposed in Earlier Congresses
Recommended from our members
Exemptions for Firearms in Bankruptcy
The U.S. Supreme Court's decisions regarding the nature of the people's right to "keep and bear arms," as guaranteed in the Second Amendment to the U.S. Constitution, has focused some interest on the extent to which firearms are protected from the reach of creditors under either federal or state laws. State laws protecting certain property from creditors' claims may be used both in and outside of the bankruptcy context. Federal law may also protect certain property from creditors' claims in bankruptcy
Restorative Justice Pilot Project at the Parentage and Child Support Court of the Circuit Court of Cook County
Mechanistic Studies of Ethylene Hydrophenylation Catalyzed by Bipyridyl Pt(II) Complexes
This article discusses mechanistic studies of ethylene hydrophenylation catalyzed by bipyridyl Pt(II) complexes
Dispersal and reproductive careers of male mountain gorillas in Bwindi Impenetrable National Park, Uganda
Dispersal is a key event in the life of an animal and it influences individual reproductive success. Male mountain gorillas exhibit both philopatry and dispersal, resulting in a mixed one-male and multimale social organization. However, little is known about the relationship between male dispersal or philopatry and reproductive careers in Bwindi mountain gorillas. Here we analyze data spanning from 1993 to 2017 on social groups in Bwindi Impenetrable National Park, Uganda to examine the proportion of males that disperse, age of dispersal, pathways to attaining alpha status, fate of dispersing males and philopatric males, and male tenure length as well as make comparisons of these variables to the Virunga mountain gorilla population. We report previously undocumented cases of dispersal by immature males and old males and we also observed the only known case of a fully mature male immigrating into a breeding group. We used genetic tracking of known individuals to estimate that a minimum of 25% of males that disperse to become solitary males eventually form new groups. No differences were found between the Bwindi and Virunga population in the age of male dispersal, the proportion of males that disperse, the age of alpha male acquisition, and dominance tenure length. The lack of differences may be due to small sample sizes or because the observed ecological variability does not lead to life history differences between the populations. Males in both populations follow variable strategies to attain alpha status leading to the variable one-male and multimale social organization, including dispersal to become solitary and eventually form a group, via group fissioning, usurping another alpha male, or inheriting the alpha position when a previous group leader dies
Counteranion and Solvent Assistance in Ruthenium-Mediated Alkyne to Vinylidene Isomerizations
The complex [Cp*RuCl(iPr2PNHPy)] (1) reacts with 1-alkynes HC≡CR (R = COOMe, C6H4CF3) in
dichloromethane furnishing the corresponding vinylidene complexes [Cp*Ru≡C≡CHR(iPr2PNHPy)]Cl (R = COOMe (2a-
Cl), C6H4CF3 (2b-Cl)), whereas reaction of 1 with NaBPh4 in MeOH followed by addition of HC≡CR (R = COOMe,
C6H4CF3) yields the metastable π-alkyne complexes [Cp*Ru(η2-HC≡CR)(iPr2PNHPy)][BPh4] (R = COOMe (3a-BPh4),
C6H4CF3 (3b-BPh4)). The transformation of 3a-BPh4/3b-BPh4 into their respective vinylidene isomers in dichloromethane is
very slow and requires hours to its completion. However, this process is accelerated by addition of LiCl in methanol solution.
Reaction of 1 with HC≡CR (R = COOMe, C6H4CF3) in MeOH goes through the intermediacy of the π-alkyne complexes
[Cp*Ru(η2-HC≡CR)(iPr2PNHPy)]Cl (R = COOMe (3a-Cl), C6H4CF3 (3b-Cl)), which rearrange to vinylidenes in minutes,
i.e., much faster than their counterparts containing the [BPh4]− anion. The kinetics of these isomerizations has been studied in
solution by NMR. With the help of DFT studies, these observations have been interpreted in terms of chloride- and methanolassisted
hydrogen migrations. Calculations suggest participation of a hydrido−alkynyl intermediate in the process, in which the
hydrogen atom can be transferred from the metal to the β-carbon by means of species with weak basic character acting as proton
shuttles
Catalytic Transformations of Alkynes via Ruthenium Vinylidene and Allenylidene Intermediates
NOTICE: This is the peer reviewed version of the following book chapter: Varela J. A., González-RodrÃguez C., Saá C. (2014). Catalytic Transformations of Alkynes via Ruthenium Vinylidene and Allenylidene Intermediates. In: Dixneuf P., Bruneau C. (eds) Ruthenium in Catalysis. Topics in Organometallic Chemistry, vol 48, pp. 237-287. Springer, Cham. [doi: 10.1007/3418_2014_81]. This article may be used for non-commercial purposes in accordance with Springer Verlag Terms and Conditions for self-archiving.Vinylidenes are high-energy tautomers of terminal alkynes and they can be stabilized by coordination with transition metals. The resulting metal-vinylidene species have interesting chemical properties that make their reactivity different to that of the free and metal Ï€-coordinated alkynes: the carbon α to the metal is electrophilic whereas the β carbon is nucleophilic. Ruthenium is one of the most commonly used transition metals to stabilize vinylidenes and the resulting species can undergo a range of useful transformations. The most remarkable transformations are the regioselective anti-Markovnikov addition of different nucleophiles to catalytic ruthenium vinylidenes and the participation of the Ï€ system of catalytic ruthenium vinylidenes in pericyclic reactions. Ruthenium vinylidenes have also been employed as precatalysts in ring closing metathesis (RCM) or ring opening metathesis polymerization (ROMP).
Allenylidenes could be considered as divalent radicals derived from allenes. In a similar way to vinylidenes, allenylidenes can be stabilized by coordination with transition metals and again ruthenium is one of the most widely used metals. Metalallenylidene complexes can be easily obtained from terminal propargylic alcohols by dehydration of the initially formed metal-hydroxyvinylidenes, in which the reactivity of these metal complexes is based on the electrophilic nature of Cα and Cγ, while Cβ is nucleophilic. Catalytic processes based on nucleophilic additions and pericyclic reactions involving the π system of ruthenium allenylidenes afford interesting new structures with high selectivity and atom economy
Homo- and heteroleptic alkoxycarbene f-element complexes and their reactivity towards acidic N-H and C-H bonds
The reactivity of a series of organometallic rare earth and actinide complexes with hemilabile NHC-ligands towards substrates with acidic C–H and N–H bonds is described. The synthesis, characterisation and X-ray structures of the new heteroleptic mono- and bis(NHC) cyclopentadienyl complexes LnCp2(L) 1 (Ln = Sc, Y, Ce; L = alkoxy-tethered carbene [OCMe2CH2(1-C{NCHCHNiPr})]), LnCp(L)2 (Ln = Y) 2, and the homoleptic tetrakis(NHC) complex Th(L)44 are described. The reactivity of these complexes, and of the homoleptic complexes Ln(L)3 (Ln = Sc 3, Ce), with E–H substrates is described, where EH = pyrrole C4H4NH, indole C8H6NH, diphenylacetone Ph2CC(O)Me, terminal alkynes RC[triple bond, length as m-dash]CH (R = Me3Si, Ph), and cyclopentadiene C5H6. Complex 1-Y heterolytically cleaves and adds pyrrole and indole N–H across the metal carbene bond, whereas 1-Ce does not, although 3 and 4 form H-bonded adducts. Complexes 1-Y and 1-Sc form adducts with CpH without cleaving the acidic C–H bond, 1-Ce cleaves the Cp–H bond, but 2 reacts to form the very rare H+–[C5H5]−–H+ motif. Complex 1-Ce cleaves alkyne C–H bonds but the products rearrange upon formation, while complex 1-Y cleaves the C–H bond in diphenylacetone forming a product which rearranges to the Y–O bonded enolate product
- …