Aroylphosphanes: base-free synthesis and their coordination chemistry with platinum-group metals

A series of aroylphosphanes have been prepared in good yield by base-free condensation of the respective aroyl chloride and HPPh2. Alongside the cyclophane m-{-C(O)- C6H4(C(O)PMe)}2 (1), the IR spectroscopic signatures of C6H4R{C(O)PPh2} (R = 3-Me 2, 3-CH2Cl 3, 4-CO2Me 4, 4-CN 5) and the bis(aroylphosphanes) C6H4{2,6-C(O)PPh2}2 (6) and C6H3N{2,6-C(O)PPh2}2 (7) are consistent with a manifestation of “phosphomide” character; however, weight of evidence suggests negligible contribution from this canonical form. Comparison is drawn to the structurally characterised O=P(C6H5Me-2)3 (8) in which the lone pair is sequestered. The coordination of 2–5 to rhodium(I), palladium(II) and platinum(II) is described, affording rare examples of aroylphosphane complexes of the platinum-group metals

Equity and power in a cooperative trial-and-error game

General solution concepts in cooperative game theory are static, e.g., the core, the Shapley value and the Nash bargaining solution. Dynamic implementation procedures have been proposed in order to support these static solution concepts. This thesis studies an N-dimensional Markov chain motivated by a dynamic interactive trial-and-error learning model. The state space of the Markov chain is based on a cooperative game (v,N) whose characteristic function v is superadditive and monotone, with conditions on v ensuring non-emptiness of the core. Agents repeatedly bargain over a cooperative surplus by submitting their demand for their share. Each round the payable coalition is chosen, the feasible coalition with the maximum sum of demands. Players in the payable coalition receive their demands as payoffs, the other players receive no payoff. Players adjust their demands according to the following rule: In an efficient state (where the demand sum of all players equals the total surplus, 1) one player is chosen uniformly at random and increases his demand by ε. If demands sum to 1 + ε, one player not in the payable coalition is then chosen to reduce her demand with probability proportional to the size of her demand. An individual’s demand update decision in the learning model is based solely on the observation of his last payoff. Individual updates are in the tradition of reinforcement learning, aspiration adaption, and fictitious play. Selten (1972) found empirical evidence for an inherent equity principle in many outcomes of experimental cooperative bargaining games. By construction, the dynamic learning model presented in this thesis also has an inherent equity principle. The model is a simple modification (and the limit process) of a model introduced by Nax (2010). To our knowledge, this thesis presents the first general results of such a dynamic learning model for general 3-player games and all interesting cases of 4-player games. The transition probabilities of the Markov process studied in this thesis are the transition probabilities between efficient states, obtained by the two steps from an efficient state to a state with demand sum 1+ε and back, of the described trial and error process. The process is a biased random walk on the simplex of efficient states, of which the polytope formed by the grid of core points forms the subset of particular interest. For general N-player games we introduce a coalition structure that exhibits an asymmetry of power between its members: the asymmetric coalition set. We believe the concept of an asymmetric coalition set to be both novel and relevant to the study of dynamic learning models with incremental demand updates for general cooperative games. Along a face of the core polytope generated by an asymmetric coalition set, the asymmetric face, the bias of the process is determined by the interplay between two dynamics: the inherent equity bias, which “drags” the process towards equity, and the asymmetric power, which “drags” the process away from equity. If the core polytope does not contain an asymmetric face, the equity bias of the random walk determines the expected movement along the faces of the polytope. The process can only leave the core polytope from a state on an asymmetric face. We study a special Markov chain in dimension N derived from the N-player bargaining game, where no coalitional constraints are present. Then the bias of the random walk is solely determined by the inherent equity principle: the random walk drifts towards equity, and the equilibrium distribution is concentrated around the equal split, the most equitable allocation. For N = 3, no asymmetric coalition set exists. We show that the set of recurrent states of the Markov chain is the “core polygon”, formed by the grid points in the core. The cooperative outcome co is the unique vector in the core with smallest L2-distance from the equal split. At every state of the core polygon outside a small ball around co, the random walk moves in expectation over one time step towards co. The equilibrium distribution of the Markov chain is concentrated around the vector co. For 3-player games this vector equals the egalitarian allocation, a concept developed by Dutta and Ray (1989). For N ≥ 4, games (v,N) can contain an asymmetric coalition set. For N = 4 the only possible asymmetric coalition set is formed by two distinct two player coalitions. We give three example games (v,4) with combinatorially isomorphic core. Each of the example games has an asymmetric edge in the core. Along the asymmetric edge the inherent equity bias creates a drift dynamic “down” the asymmetric edge, and the asymmetric power creates a drift dynamic “up” the asymmetric edge. In each example game the asymmetric power is extreme, zero or moderate respectively: the equilibrium distribution of the process is concentrated at the “upper” endpoint, the “lower” endpoint (which is co) or around a demand vector in the interior of the asymmetric edge. Furthermore we give simulation results, which indicate that the concept of asymmetric power can be generalized to other dynamic learning processes. Coupling is a powerful and elegant probabilistic tool with which one is often able to calculate tight bounds on the speed of convergence to equilibrium of Markov chains. We believe this technique to be novel to the study of dynamic stochastic learning processes in evolutionary game theory and hence present a general introduction to the technique. We use coupling arguments to show rapid mixing for the cooperative game process for the N-player bargaining game and for general 3-player games

Triamidoamine-uranium(IV)-stabilized terminal parent phosphide and phosphinidene complexes

Reaction of [U(TrenTIPS)(THF)][BPh4] (1; TrenTIPS=N{CH2CH2NSi(iPr)3}3) with NaPH2 afforded the novel f-block terminal parent phosphide complex [U(TrenTIPS)(PH2)] (2; U–P=2.883(2) Å). Treatment of 2 with one equivalent of KCH2C6H5 and two equivalents of benzo-15-crown-5 ether (B15C5) afforded the unprecedented metal-stabilized terminal parent phosphinidene complex [U(TrenTIPS)(PH)][K(B15C5)2] (4; U[DOUBLE BOND]P=2.613(2) Å). DFT calculations reveal a polarized-covalent U[DOUBLE BOND]P bond with a Mayer bond order of 1.92

(5-Ammonio­pent­yl)triphenyl­phospho­nium dibromide ethanol solvate

The alkyl­ammonium chain of the dication in the title mitochondrially targeted (5-ammonio­pent­yl)triphenyl­­phos­pho­nium dibromide ethanol solvate, C23H28NP2+·2Br−·C2H6O, is almost planar (r.m.s deviation = 0.0716 Å for all non-H atoms) and in the extended form, maximizing the P⋯N distance [7.716 (2) Å]. The ions and solvent are linked within the crystal by N—H⋯Br, N—H⋯O and O—H⋯Br hydrogen-bonding inter­actions, forming C 3 2(6) chains along the b axis, with secondary C—H⋯Br and C—H⋯O inter­actions cross-linking the chains

Flow restoration during mechanical thrombectomy for large vessel occlusion is associated with an immediate reduction of systemic blood pressure

Introduction: Managing blood pressure in patients with large vessel occlusion affects infarct size and clinical outcomes. We examined how restoring blood flow impacts systemic blood pressure during mechanical thrombectomy. Patients and Methods: Patients with large vessel occlusion in the anterior circulation undergoing mechanical thrombectomy between June 2016 and January 2018 were screened. We included those treated under local anesthesia or conscious sedation and analyzed standardized anesthesia protocols to assess systolic and diastolic blood pressure levels throughout the procedure. The primary outcome was the change of blood pressure, compared 5 min before versus 5 min after the last recanalization attempt. Successful reperfusion was defined as Thrombolysis in Cerebral Infarction score ⩾ 2b. Results: Of 134 patients, 117 (87%) achieved successful angiographic reperfusion, showing a notable systolic blood pressure drop 5 min after flow restoration (10.2 ± 14.6 vs 3.24 ± 8.65 mm Hg, p = 0.009). Successful angiographic reperfusion was a significant predictor for this decrease in multivariable logistic regression: OR = 1.34 (95% CI: 1.03–1.73, p = 0.0299). Among 66 patients not given circulation-affecting meds, a significant systolic pressure reduction was also observed (155 ± 17 mm Hg to 148 ± 17 mm Hg ; p < 0.001). No diastolic pressure changes were significant. Discussion and Conclusions: Flow restoration was associated with an immediate reduction of systolic blood pressure values in patients undergoing mechanical recanalization under local anesthesia or conscious sedation. This suggests a complex interplay between endovascular stroke therapy and cardiovascular hemodynamics

Tris(4-tert-butyl­phen­yl)phosphine oxide

In the title compound, C30H39OP, the P=O bond length is 1.4866 (12) Å and the P—C bond lengths range from 1.804 (2) to 1.808 (13) Å. The molecle is located on a crystallographic mirror plane. The methyl groups of one tert-butyl group are disordered over two sites in a 0.776 (4):0.224 (4) ratio

Clinical characteristics, causes and predictors of outcomes in patients with in-hospital cardiac arrest:results from the SURVIVE-ARREST study

Introduction: In-hospital cardiac arrest (IHCA) is acutely life-threatening and remains associated with high mortality and morbidity. Identifying predictors of mortality after IHCA would help to guide acute therapy. Methods: We determined patient characteristics and independent predictors of 30-day in-hospital mortality, neurological outcome, and discharge/referral pathways in patients experiencing IHCA in a large tertiary care hospital between January 2014 and April 2017. Multivariable Cox regression model was fitted to assess predictors of outcomes. Results: A total of 368 patients with IHCA were analysed (median age 73 years (interquartile range 65–78), 123 (33.4%) women). Most patients (45.9%) had an initial non-shockable rhythm and shockable rhythms were found in 20.9%; 23.6% of patients suffered from a recurrent episode of cardiac arrest. 172/368 patients died within 30 days (46.7%). Of 196/368 patients discharged alive after IHCA, the majority (72.9%, n = 143) had a good functional neurological outcome (modified Rankin Scale ≤ 3 points). In the multivariable analysis, return of spontaneous circulation without mechanical circulatory support (hazard ratio (HR) 0.36, 95% confidence interval (CI) 0.21–0.64), invasive coronary angiography and/or percutaneous intervention (HR 0.56, 95% CI 0.34–0.92), and antibiotic therapy (HR 0.87, 95% CI 0.83–0.92) were associated with a lower risk of 30-day in hospital mortality. Conclusion: In the present study, IHCA was survived in ~ 50% in a tertiary care hospital, although only a minority of patients presented with shockable rhythms. The majority of IHCA survivors (~ 70%) had a good neurological outcome. Recovery of spontaneous circulation and presence of treatable acute causes of the arrest are associated with better survival. Graphical abstract: Clinical Characteristics, Causes and Predictors of Outcomes in Patients with In-Hospital Cardiac Arrest: Results from the SURVIVE-ARREST Study. Abbreviations: CPR, cardiopulmonary resuscitation; IHCA, In-hospital cardiac arrest; MCS, mechanical circulatory support; PCI, percutaneous coronary intervention; ROSC, return of spontaneous circulation; SBP, systolic blood pressure. [Figure not available: see fulltext.].</p

Rapid Metal-Free Formation of Free Phosphines from Phosphine Oxides

A rapid method for the reduction of secondary phosphine oxides under mild conditions has been developed, allowing simple isolation of the corresponding free phosphines. The methodology involves the use of pinacol borane (HBpin) to effect the reduction while circumventing the formation of a phosphine borane adduct, as is usually the case with various other commonly used borane reducing agents such as borane tetrahydrofuran complex (BH 3⋅THF) and borane dimethyl sulfide complex (BH 3⋅SMe 2). In addition, this methodology requires only a small excess of reducing agent and therefore compares favourably not just with other borane reductants that do not require a metal co-catalyst, but also with silane and aluminium based reagents. (Figure presented.). </p