Gabriel Ménard

Room temperature reduction of CO2 to methanol by Al-based frustrated Lewis pairs and ammonia borane.

AlX(3) (X = Cl or Br) and PMes(3) (Mes = 2,4,6-C(6)H(2)Me(3)) react to form weak Lewis adducts but also react with CO(2) to give Mes(3)P(CO(2))(AlX(3))(2) (X = Cl; Br). These species react rapidly with excess ammonia borane at room temperature to give CH(3)OH upon quenching with water.

C–H Bond Activation by Radical Ion Pairs Derived from R3P/Al(C6F5)3 Frustrated Lewis Pairs and N2O

Al(C6F5)3/R3P [R = tert-butyl (tBu), mesityl (Mes), naphthyl (Nap)] frustrated Lewis pairs react with N2O to form species having the formula R3P(N2O)Al(C6F5)3, which react with additional alane to generate proposed frustrated radical ion pairs formulated as [R3P·][(μ-O·)(Al(C6F5)3)2] that can activate C-H bonds. For R = tBu, C-H activation of a tBu group affords [tBu2PMe(C(CH2)Me)][(μ-OH)(Al(C6F5)3)2]. In the case of R = Mes, the radical cation salt [Mes3P·][(μ-HO)(Al(C6F5)3)2] is isolated, while for R = Nap, the activation of toluene and bromobenzene gives [(Nap)3PCH2Ph][(μ-OH)(Al(C6F5)3)2] and [(Nap)3PC6H4Br][(μ-HO)(Al(C6F5)3)2], respectively.

Microfluidic studies of CO2 sequestration by frustrated Lewis pairs.

Frustrated Lewis pairs (FLPs) comprising sterically hindered Lewis acids and bases offer the capability to reversibly capture CO2 under mild reaction conditions. The determination of equilibrium constants and thermodynamic properties of these reactions should enable assessment of the efficiency of a particular FLP system for CO2 sequestration and provide insights for design of new, efficient formulations of FLP catalysts for CO2 capture. We have developed a microfluidic approach to studies of FLP-CO2 reactions, which provides their thermodynamic characterization that is not accessible otherwise. The approach enables the determination of the equilibrium reaction constants at different temperatures, the enthalpy, the entropy, and the Gibbs energy of these reactions, as well as the enhancement factor. The microfluidic methodology has been validated by applying it to the well-characterized reaction of CO2 with a secondary amine. The microfluidic approach can be applied for fundamental thermodynamic studies of other gas-liquid reactions.

Exchange chemistry of tBu3P(CO2)B(C6F5)2Cl

Halide exchange from the species tBu(3)P(CO(2))B(C(6)F(5))(2)Cl 1 with Me(3)SiOSO(2)CF(3) gave tBu(3)P(CO(2))B(C(6)F(5))(2)(OSO(2)CF(3)) 2. Similarly, Lewis acid exchange occurs in reactions of 1 with Al(C(6)F(5))(3) and [Cp(2)TiMe][B(C(6)F(5))(4)] affording the products, tBu(3)P(CO(2))Al(C(6)F(5))(3)3 and [tBu(3)P(CO(2))TiCp(2)Cl][B(C(6)F(5))(4)] 4.

Maximizing Electron Exchange in a [Fe3] Cluster

The one-electron reduction of ((tbs)L)Fe₃(thf)¹ furnishes [M][((tbs)L)Fe₃] ([M]⁺ = [(18-C-6)K(thf)₂]⁺ (1, 76%) or [(crypt-222)K]⁺ (2, 54%)). Upon reduction, the ligand (tbs)L⁶⁻ rearranges around the triiron core to adopt an almost ideal C₃-symmetry. Accompanying the ((tbs)L) ligand rearrangement, the THF bound to the neutral starting material is expelled, and the Fe-Fe distances within the trinuclear cluster contract by ∼0.13 Å in 1. Variable-temperature magnetic susceptibility data indicates a well-isolated S = 11/2 spin ground state that persists to room temperature. Slow magnetic relaxation is observed at low temperature as evidenced by the out-of-phase (χ(M)″) component of the alternating current (ac) magnetic susceptibility data and by the appearance of hyperfine splitting in the zero-field ⁵⁷Fe Mössbauer spectra at 4.2 K. Analysis of the ac magnetic susceptibility yields an effective spin reversal barrier (U(eff)) of 22.6(2) cm⁻¹, nearly matching the theoretical barrier of 38.7 cm⁻¹ calculated from the axial zero-field splitting parameter (D = -1.29 cm⁻¹) extracted from the reduced magnetization data. A polycrystalline sample of 1 displays three sextets in the Mössbauer spectrum at 4.2 K (H(ext) = 0) which converge to a single six-line pattern in a frozen 2-MeTHF glass sample, indicating a unique iron environment and thus strong electron delocalization. The spin ground state and ligand rearrangement are discussed within the framework of a fully delocalized cluster exhibiting strong double and direct exchange interactions.

Environmental non-governmental organizations: key players in development in a changing climate—a case study of Mali

Developing countries are often most impacted by climate change. While the work of international environmental organizations has received considerable public and academic attention, local environmental non-governmental organizations (ENGOs) also play a key role in assisting local populations adapt to the changing environment and develop in a sustainable manner. Drawing on data from semi-structured interviews with rural Malians, and using a local ENGO [the Mali-Folkecenter Nyetaa (MFC)] as a case study, this paper begins by describing how rural Malians perceive climate change is impacting their lives, and how the MFC attempts to address these impacts with their programs in the communities. The paper then illustrates the unique advantages of local ENGOs, both in their holistic approach and their integration in the communities, to working with the local population, relative to the approach taken by larger NGOs in this field. It concludes by proposing that a key new avenue for the international community to meet its developmental and environmental goals could be to support the work of local ENGOs through, for example, existing carbon markets.

Colonial past, voluntary association and far-right voting in France

We examine whether linked pluralism – association membership along cross-cutting lines – reduces the likelihood of voting for the far right. Data come from surveys of European ex-colonials (pieds noirs) conducted after the French national elections of 2002, 2007 and 2012. Results confirm that pied-noir support for far-right candidates in presidential and parliamentary elections greatly exceeded the average. This pattern was mediated by membership in voluntary associations: far-right voting was significantly higher among those whose association membership insulated them from countering influences. Our study demonstrates the importance for far-right studies of the distinction between bridging and bonding social capital. The effects on politics of Frances colonial legacy depend on association membership, which can either uphold or cross social cleavages.

A Mono-, Di-, and Trivanadocene Phosphorus Oxide Series: Synthesis, Magnetism, and Chemical/Electrochemical Properties

In this Article, we outline the synthesis of B(C6F5)3-coordinated mono-, di-, and trivanadocene phosphorus oxide complexes, Cp2VOP(OB(C6F5)3)Ph2 (2), (Cp2VO)2P(OB(C6F5)3)Ph (3), and (Cp2VO)3P(OB(C6F5)3) (4), respectively (Cp = η5-cyclopentadienyl). The complexes were synthesized from the known reagents, Cp2VF and Ph2P(O)OSiMe3 (for 2) or PhP(O)(OSiMe3)2 (for 3) or (Me3SiO)3PO (for 4), via Me3SiF elimination and in the presence of B(C6F5)3. The multimetallic complexes (3 and 4) could not be synthesized without the capping B(C6F5)3 Lewis acid, whereas the uncapped version of 2, Cp2VOP(O)Ph2 (1), has previously been reported by us. Spectroscopic and crystallographic analyses of 2-4 support an increasingly Lewis basic P═O bond upon substitution of -Ph for -OVCp2 fragments (2-4). The increased metal nuclearity also results in increasingly reducing complexes as evidenced by cyclic voltammetry (CV). Magnetic measurements (SQUID) further revealed high-spin complexes with negligible magnetic exchange between V centers. Chemical oxidation of 2 with 0.5 equiv of [Ag][B(C6F5)4] resulted in a ligand rearrangement reaction producing the VIV product, Cp2V(OP(OB(C6F5)3)Ph2)2 (7). In contrast, the oxidation of 4 with the trityl salt, [Ph3C][B(C6F5)4], resulted in the isolation of a mixed-valent VIII/VIV dimetallic species, (Cp2VO2P(OB(C6F5)3)OVCp2 (9). Both oxidations likely produce the [Cp2V][B(C6F5)4] byproduct and evidence for its formation is presented. The synthesis and characterization of the mono- and dimetallic species, Cp2VOP(OBPh3)Ph2 (8) and (Cp2VO)2P(OB(C6F5)3)OSiMe3 (5), is also reported.

Copyright, digital sharing, and the liberal order: sociolegal constructions of intellectual property in the era of mass digitization

Intellectual property (IP) rights policy has long been driven by rights-holder interests, leading to IP regimes focused on protecting private property at the expense of broadening public access to cultural works. The rise of instant, low-cost digital sharing practices, however, forces the sociolegal construction of IP as ‘property’ into crisis by contradicting the conception of creative works as commodities that can be exclusively ‘owned’ and exchanged. This cuts into a classic social science debate over how best to balance individual rights against collective interests, which has played out in liberal society through tensions between contradictory principles seeking to uphold the sanctity of private property (the principle of ‘Individual Freedom’) while also correcting social inequality (the ‘Equal Means’ principle). While IP policy has historically developed largely in accordance with Individual Freedom, digital sharing of creative works is premised instead on Equal Means. As these forces collide, the question at stake is whether crisis in the status quo conception of property rights disrupts existing power relations, with implications for the logic of policy development in the digital age. To address this question, I test for continuity of the predominant trend in IP policy-making using recent legislative changes to the Canadian copyright regime. I find that, contrary to expectations, policy changes do not manifestly favor rights-holders. Rather, legislative outcomes are split between modest protections for rights-holders and clear gains for rights of open access. I take this as evidence of the increasing complexification of IP policy in response to mass digitization.