Hydrolysis of cyclic phosphoramides. Evidence for syn lone pair catalysis

Núñez, Andrés; Berroterán, Dyanna; Núñez, Oswaldo

doi:10.1039/b300916e

Cited by 9 publications

(2 citation statements)

References 25 publications

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“…Expected Properties and Suggestions for the Synthesis. The pH value of the monomeric model compound of PEI, N , N ‘-dimethylethylenediamine, is 9.9, close to that (∼10) of PEI PMEIEO and PEIEO are expected not to be so basic and cytotoxic as PEI.…”

Section: Resultsmentioning

confidence: 72%

Prediction of Structures, Properties, and Functions of Alternating Copolymers of Ethylene Imine and Ethylene Oxide As an Example of Molecular Design for Polymers

2006

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Conformational analysis of two alternating copolymers, poly(ethylene imine-alt-ethylene oxide) (PEIEO) and poly(N-methylethylene imine-alt-ethylene oxide) (PMEIEO), has been carried out by the inversionalrotational isomeric state (IRIS) analysis of ab initio molecular orbital (MO) calculations and 1 H and 13 C NMR experiments for their model compounds. On the basis of the conformational energies derived therefrom and molecular mechanics and MO calculations, higher-order structures, physical properties, and functions of the two copolymers have been predicted as an example of molecular design. These copolymers are expected to form various hydrogen bonds: PEIEO, N-H‚‚‚O (interaction energy, -1.75 kcal mol -1 ), C-H‚‚‚N (-0.68 kcal mol -1 ), and C-H‚‚‚O (-0.21 kcal mol -1 ); PMEIEO, C-H‚‚‚N (-0.66 kcal mol -1 ), and C-H‚‚‚O (-0.41 kcal mol -1 ). In particular, the N-H‚‚‚O hydrogen bond of PEIEO is too strong to be broken even by protic solvents such as methanol and water but replaced by an intermolecular N-H‚‚‚OdS attraction in dimethyl sulfoxide. The C-N and C-O bonds of PEIEO prefer the trans state as found for poly(ethylene imine) (PEI) and poly-(ethylene oxide), whereas the C-C bond does not have its own conformational preference and its conformational equilibrium is determined only by the hydrogen bond strength (HBS). The characteristic ratio of PEIEO largely depends on HBS: 1.5 (HBS ) 100%); 6.5 (0%). In contrast, the weak hydrogen bonds of PMEIEO little affect the characteristic ratio; 5.2 (HBS ) 100%); 5.9 (0%). According to Mattice's analysis (Macromolecules 2004, 37, 4711), PEIEO and PEI tend to form circular paths due to the intramolecular hydrogen bonds. Both molecular mechanics calculations using the Amber force field and density functional MO calculations under the periodic boundary condition have suggested that a double-helical structure may be formed in the PEIEO crystal. The possibility that these copolymers will be utilized as gene carriers and ion conductors is discussed, and the synthetic method is also suggested. In conclusion, these copolymers should be promising and deserve to be synthesized.

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Section: Resultsmentioning

confidence: 72%

Prediction of Structures, Properties, and Functions of Alternating Copolymers of Ethylene Imine and Ethylene Oxide As an Example of Molecular Design for Polymers

2006

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“…The enhanced reactivity of selected cyclic phosphates over their acyclic counterparts is well known [61][62][63][64][65][66] ; with rates of hydrolysis and solvolysis up to a million times faster for cyclic species. The relative stability of phosphoramidic difluorides (9) to phosphoramidofluoridates (10 and 12) can be explained using an electronic rationale; having two highly electronegative fluorine atoms bonded to the phosphorus atom creates a substantially more positive P(V) core, leading to increased rates of hydrolysis and decomposition 67 .…”

Section: Resultsmentioning

confidence: 99%

Phosphorus(V) Fluoride Exchange (PFEx): Multidimensional Click Chemistry from Phosphorus(V) Connective Hubs

Sun

Smedley

Homer

et al. 2022

Preprint

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We report catalytic Phosphorus Fluoride Exchange (PFEx) as the latest advance in connective click-reaction technology. Emulating Nature, PFEx reaches into the biological world and creates stable tetrahedral P(V)- connections through efficient phosphorus-fluoride exchange chemistry. We showcase PFEx through the coupling of P(V)-F hubs with aryl alcohols, alkyl alcohols, and amines, delivering stable, multidimensional P(V)-O and P(V)- N connected products. The reactivity profile of P-F hubs surpasses that of their P-Cl counterparts, both in reaction performance, rate, and outcome, qualifying PFEx as a true click reaction. The rate of PFEx transformations is significantly enhanced by Lewis amine base catalysis [e.g., 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD)]. When using substrates comprising multiple P-F bonds, selective, serial exchange reactions are realized through judicious catalyst selection. Synthesis of the final products (in up to 4 steps) allows controlled projections to be deliberately installed along 3 of the 4 tetrahedral axes departing the P(V) central hub. The unique reactivity window of PFEx allows for selective, modular click-reactions to be performed in series (e.g., SuFEx-PFEx-CuAAC) to rapidly generate complex multidimensional molecules, rendering PFEX a perfect addition to the click chemistry toolbox.

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Interplay of thermochemistry and Structural Chemistry, the journal (volume 18, 2007) and the discipline

Ponikvar

Liebman

2008

Struct Chem

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In this study, we relate the contents of the journal Structural Chemistry for the calendar year 2007 and thermochemistry. The year's articles were briefly summarized and a thermochemical comment written to supplement them. Frequently questions were asked and future research was suggested.Keywords Structural Chemistry Á Thermochemistry Á Thermodynamics Á Enthalpy of formation Á Enthalpy of phase change Á Enthalpy of reaction As practiced disciplines, structural chemistry and thermochemistry are very often unrelated. In this study, these disciplines are linked as relations are explicitly made using the contents of the journal Structural Chemistry (Vol. 18) for the calendar year 2007 as a scaffold for our analysis, for our selected articles in the discipline of structural chemistry. These studies have been reviewed by us, where we give them a thermochemical flavor. While this commentary is most generally written in terms of brief summaries of literature papers involving enthalpies of formation and/or reaction, not uncommonly we raise questions and even suggest possible future research. We are not, however, going to give a thermochemical slant on book reviews, honorary dedications, and obituaries although these works will be cited in our text.As such, this article is a sequel to our earlier related reviews of Structural Chemistry for the calendar years 2000 through 2004 [1-5]. Reviews for 2005 and 2006 are currently being prepared. Issue 1In the first article in the first issue of Structural Chemistry for 2007, Hargittai [6] asserted that while research is currently usually carried out in big groups, the most important ideas, observations and discoveries still belong to individuals who have to bring down dogmas or open entirely new areas in science. This may bring solace to the thermochemical community in which research groups are generally small, and the number of new practitioners sadly few.In the past decade, the crystal engineering of multidimensional arrays and networks containing metal ions has achieved considerable progress because of the increased interest in the potential utility of these compounds as zeolite-like materials [7-11], catalysts [12], or magnetic materials [13][14][15]. The thermochemistry of these species is complicated by their inherent complexity: however, estimation approaches of their key thermochemical quantities are increasingly reliable [16]. In the second article of this issue, by Wang et al. [17], the versatility of malonate dianion as a ligand for the construction of extended networks with different topologies dependent on the coordination geometry of the metal ion was discussed. The synthesis and structure of a novel malonate-bridged copper(II) compound in which copper(II) ions have two different coordination environments in a novel three-dimensional (3D) network was described. Metal malonates have been studied from a

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Hydrolysis of cyclic phosphoramides. Evidence for syn lone pair catalysis

Cited by 9 publications

References 25 publications

Prediction of Structures, Properties, and Functions of Alternating Copolymers of Ethylene Imine and Ethylene Oxide As an Example of Molecular Design for Polymers

Prediction of Structures, Properties, and Functions of Alternating Copolymers of Ethylene Imine and Ethylene Oxide As an Example of Molecular Design for Polymers

Phosphorus(V) Fluoride Exchange (PFEx): Multidimensional Click Chemistry from Phosphorus(V) Connective Hubs

Interplay of thermochemistry and Structural Chemistry, the journal (volume 18, 2007) and the discipline

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