Cooperative Initiation in a Dinuclear Indium Complex for CO2 Epoxide Copolymerization.

Dinuclear indium complexes have been synthesized and characterized. These include neutral and cationic indium complexes supported by a Schiff base ligand bearing a binaphthol linker. The new compounds were investigated for alternating copolymerization of CO2 and cyclohexene oxide. In particular, the neutral indium chloride complex (±)-[(ONapNiN)InCl2]2 (4) showed high conversion of cyclohexene oxide and selectivity for poly(cyclohexene carbonate) formation without cocatalysts at 80 °C under various CO2 pressures (2-30 bar). Importantly, the reactivity of the dinuclear indium chloride complex 4 is drastically different from that of the mononuclear indium chloride complex (±)-(NNiOtBu)InCl2 (5), suggesting a cooperative initiation mechanism involving the two indium centers in 4.

Indium-Catalyzed CO2/Epoxide Copolymerization: Enhancing Reactivity with a Hemilabile Phosphine Donor.

Group 13 metal complexes have emerged as powerful catalysts for transforming CO2 into added-value products. However, direct comparisons of reactivity between Al, Ga, and In catalysts are rare. We report aluminum (1), gallium (2), and indium (3) complexes supported by a half-salen H[PNNO] ligand with a pendent phosphine donor and investigate their activity as catalysts for the copolymerization of CO2 and cyclohexene oxide. In solution, the P-donor is dissociated for the Al and Ga complexes while for the In complex it exhibits hemilabile behavior. The indium complex shows higher conversion and selectivity than the Al or Ga analogues. The mechanism of the reaction was studied by NMR and FTIR spectroscopy experiments as well as structural characterization of off-cycle catalytic intermediate indium trichloride complex [(PNNO)InCl3][TBA] (4). This study highlights the impact of a hemilabile phosphine group on group 13 metals and provides a detailed analysis of the initiation step in CO2/epoxide copolymerization reactions.

Developing Markov Models From Real-World Data: A Case Study of Heart Failure Modeling Using Administrative Data.

OBJECTIVES: Markov models characterize disease progression as specific health states based on clinical or biological measures. However, these measures are not always collected outside clinical trials. In this article, an alternative approach is presented that uses real-world data to define the health states and to model transitions between them, specific to a local setting, to estimate the cost-effectiveness of telemonitoring (TM) versus no TM for heart failure. METHODS: The incidence of hospitalization for usual care was estimated from hospital episode statistics (HES) data in the United Kingdom and converted into a monthly transition matrix with 5 health states (4 states are defined based on the number of hospitalizations in the previous year and death) to estimate the cost-effectiveness of TM in a local UK primary care trust (PCT) using probabilistic sensitivity analysis from a healthcare perspective. RESULTS: Geographical variation in hospitalization rates were present, which led to different health state transition matrices in different localities. In the PCT that was evaluated, TM accrued mean additional costs of £3610 and 0.075 additional quality-adjusted life-years (QALYs) compared with usual care per patient, resulting in a mean incremental cost effectiveness ratio of £48 172/QALY. CONCLUSIONS: The use of administrative data to define health states and transition matrices based on health service events is feasible, and TM was not cost-effective in our analysis. Given the increasing emphasis on using real-world evidence, it is likely that these approaches will be used more in the future.

Synthesis of High-Molecular-Weight Poly(ether-alt-ester) by Selective Double Ring-Opening Polymerization of Spiroorthoesters.

We report the selective double ring-opening polymerization of presequenced spiroorthoester monomers to form high-molecular-weight (≈90 kDa) poly(ether-alt-ester)s with a simple cationic alkyl gallium catalyst. The selective formation of double ring-opened polymer units was confirmed by NMR and IR spectroscopies. Thermal and rheological properties of homo- and copolymers were further characterized by differential scanning calorimetry, thermogravimetric analysis, and stress-controlled rotational rheometry. Linear viscoelastic moduli show that these systems are well entangled (plateau modulus), thereby possessing nearly terminal relaxation at long time scales (low frequencies) and Rouse segmental dynamics at short time scales (high frequencies) with characteristic slopes. These are the highest-molecular-weight poly(ether-alt-ester)s reported to date.

Thermally stable zinc hydride catalyst for hydrosilylation of CO2 to silyl formate at atmospheric pressure.

Neutral zinc complexes supported by H[PNNO], a diaminophenolate ligand bearing a pendant phosphine group, were synthesized and characterized. The phosphine arm adopts two different configurations in solution and prevents aggregation. The monomeric zinc hydride complex is stable at elevated temperatures up to 125 °C and reacts readily with CO2 to afford a zinc formate complex. The zinc hydride is active for CO2 hydrosilylation at atmospheric CO2 pressure and is selective for CO2 reduction to the silyl-formate product.

Telemonitoring after discharge from hospital with heart failure: cost-effectiveness modelling of alternative service designs.

OBJECTIVES: To estimate the cost-effectiveness of remote monitoring strategies versus usual care for adults recently discharged after a heart failure (HF) exacerbation. DESIGN: Decision analysis modelling of cost-effectiveness using secondary data sources. SETTING: Acute hospitals in the UK. PATIENTS: Patients recently discharged (within 28 days) after a HF exacerbation. INTERVENTIONS: Structured telephone support (STS) via human to machine (STS HM) interface, (2) STS via human to human (STS HH) contact and (3) home telemonitoring (TM), compared with (4) usual care. MAIN OUTCOME MEASURES: The incremental cost per quality-adjusted life year (QALY) gained by each strategy compared to the next most effective alternative and the probability of each strategy being cost-effective at varying willingness to pay per QALY gained. RESULTS: TM was the most cost-effective strategy in the scenario using these base case costs. Compared with usual care, TM had an estimated incremental cost effectiveness ratio (ICER) of £11 873/QALY, whereas STS HH had an ICER of £228 035/QALY against TM. STS HM was dominated by usual care. Threshold analysis suggested that the monthly cost of TM has to be higher than £390 to have an ICER greater than £20 000/QALY against STS HH. Scenario analyses performed using higher costs of usual care, higher costs of STS HH and lower costs of TM do not substantially change the conclusions. CONCLUSIONS: Cost-effectiveness analyses suggest that TM was an optimal strategy in most scenarios, but there is considerable uncertainty in relation to clear descriptions of the interventions and robust estimation of costs.