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Reductive Elimination of Alkylamines from Low-Valent, Alkylpalladium(II) Amido Complexes
Date: August 30, 2012
Creator: Hanley, Patrick S.; Marquard, Seth L.; Cundari, Thomas R., 1964- & Hartwig, John F.
Description: This article discusses reductive elimination of alkylamines from low-valent, alkylpalladium(II) amido complexes. A series of three-coordinate norbornylpalladium amido complexes ligated by bulky N-heterocyclic carbene (NHC) ligands were prepared that undergo reductive eliminations to form the alkyl-nitrogen bond of alkylamine products. The rates of reductive elimination reveal that complexes containing more-electron-donating amido groups react faster than those with less-electron-donating amido groups, and complexes containing more-sterically bulky amido groups undergo reductive elimination more slowly than complexes containing less-sterically bulky amido groups. Complexes ligated by more-electron-donating ancillary NHC ligands undergo reductive elimination faster than complexes ligated by less-electron-donating NHC ligands. In contrast to the reductive elimination of benzylamines from bisphosphine-ligated palladium amides, these reactions occur with retention of configuration at the alkyl group, indicating that these reductive eliminations proceed by a concerted pathway. The experimentally determined free energy barrier of 26 kcal/mol is close to the computed free energy barrier of 23.9 kcal/mol (363 K) for a concerted reductive elimination from the isolated, three-coordinate NHC-ligated palladium anilido complex.
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc107792/
Remote Sensing and GIS for Nonpoint Source Pollution Analysis in the City of Dallas' Eastern Watersheds
Date: June 1989
Creator: University of North Texas. Dept. of Biological Sciences
Description: This report describes the findings of a study conducted on the Eastern Watersheds of Lake Lavon, Lake Ray Hubbard, Lake Tawakoni, Lake Palestine and Lake Fork, which are located within the Blackland Prairie, Post Oak Savannah and Pineywoods provinces. These watersheds are among nine that provide drinking water to Dallas, Texas. The study examines the potential benefit of "remote sensing and geographic information systems (GIS) for watershed management" in these five watersheds (p. iii).
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc29400/
Remote Sensing and GIS for Nonpoint Source Pollution Analysis in the City of Dallas' Western Watersheds
Date: August 1988
Creator: University of North Texas. Dept. of Biological Sciences
Description: This report describes the findings of a study conducted on the watersheds of "Lake Lewisville, Lake Ray Roberts, Lake Grapevine and the Elm Fork of the Trinity River between Lake Lewisville and Frazier Dam," which are all part of the upper Trinity drainage basin (p. 31). The study examines the potential benefit of "remote sensing and geographic information systems (GIS) for watershed management" in and around Dallas, Texas (p. i).
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc29399/
Renewal and memory properties in the random growth of surfaces
Date: February 4, 2008
Creator: Cakir, Rasit; Grigolini, Paolo & Ignaccolo, Massimiliano
Description: In this article, the authors use the model of ballistic deposition as a simple way to establish cooperation among the columns of a growing surface, 'the single individual of the same society.' The authors show that cooperation generates memory properties and at same time non-Poisson renewal events. The variable generating memory can be regarded as the velocity of a particle driven by a bath with the same time scale, and the variable generating renewal processes is the corresponding diffusional coordinate.
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc132977/
Renewal, Modulation, and Superstatistics in Times Series
Date: April 27, 2006
Creator: Allegrini, Paolo; Barbi, Francesco; Grigolini, Paolo & Paradisi, Paolo
Description: In this article, the authors consider two different approaches, to which the authors refer to as renewal and modulation, to generate time series with a nonexponential distribution of waiting times. The authors show that different time series with the same waiting time distribution are not necessarily statistically equivalent, and might generate different physical properties. Renewal generates aging and anomalous scaling, while modulation yields no significant aging and either ordinary or anomalous diffusion, according to the dynamic prescription adopted. The authors show, in fact, that the physical realization of modulation generates two classes of events. The events of the first class are determined by the persistent use of the same exponential time scale for an extended lapse of time, and consequently are numerous; the events of the second class are identified with the abrupt changes from one to another exponential prescription, and consequently are rare. The events of the second class, although rare, determine the scaling of the diffusion process, and for this reason the authors term them as crucial events. According to the prescription adopted to produce modulation, the distribution density of the time distances between two consecutive crucial events might have, or not, a diverging second moment. In the ...
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc40400/
La Reserva De Biosfera Cabo De Hornos: Un Desafío Para La Conservación De La Biodiversidad E Implementación Del Desarrollo Sustentable En El Extremo Austral De América
Date: 2007
Creator: Rozzi, Ricardo, 1960-; Massardo, Francisca; Mansilla, Andrés O.; Anderson, Christopher B.; Berghöfer, Augustin; Mansilla, Miguel et al
Description: This article discusses biodiversity conservation and implementation of sustainable development in southernmost South America and the new biosphere reserve in Cape Horn, located in Antarctica Chilena Province.
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc102292/
Resistance to impact criteria can lead to a tightening of the accountability noose
Date: March 15, 2012
Creator: Holbrook, J. Britt & Frodeman, Robert
Description: This article discusses how resistance to impact criteria can lead to a tightening of the accountability noose. Vague impact criteria are a blessing in disguise. The authors write that researchers who push against criteria that allow considerable autonomy are foolish and should learn from overseas contemporaries that a clearer definition of impact requirements is not dissimilar from a tightening of the noose.
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc84357/
Response of Complex Systems to Complex Perturbations: the Complexity Matching Effect
Date: December 2006
Creator: Allegrini, Paolo; Bologna, Mauro; Grigolini, Paolo & West, Bruce J.
Description: This article discusses the complexity matching effect. The dynamical emergence (and subsequent intermittent breakdown) of collective behavior in complex systems is described as a non-Poisson renewal process, characterized by a waiting-time distribution density ψ(T) for the time intervals between successfully recorded breakdowns. In the intermittent case ψ(t) ~ t-μ, with complexity index μ. The authors show that two systems can exchange information through complexity matching and present theoretical and numerical calculations describing a system with complexity index μs perturbed by a signal with complexity index μp. The analysis focuses on the non-ergodic (non-stationary) case μ ≤ 2 showing that for μs ≥ μp, the system S statistically inherits the correlation function of the perturbation P. The condition μp = μs is a resonant maximum for correlation information exchange.
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc132965/
Response to "A critique of Abraham and Acree's correlation for deca-1,9-diene/water partition coefficients"
Date: February 1, 2013
Creator: Abraham, M. H. (Michael H.) & Acree, William E. (William Eugene)
Description: This article is a response to "A critique of Abraham and Acree's correlation for deca-1,9-diene/water partition coefficients." Abstract: The manuscript responds to the critique of Nitsche and Kasting concerning our published correlation for deca-1,9-diene-water partition coefficients. Several statements made in the critique are refuded, and shown to be misrepresentations of ideas contained in our earlier paper.
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc152438/
Response to: Use of prior odds for missing persons identifications - author's reply
Date: February 1, 2012
Creator: Budowle, Bruce; Ge, Jianye; Chakraborty, Ranajit & Gill-King, Harrell
Description: This article is in response to an authors' reply to 'Use of prior odds for missing persons identifications.' This response is to the reply by Alex Biedermann, Franco Taroni, and Pierre Margot.
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc122169/