Selective nitrogen adsorption via backbonding in a metal-organic framework with exposed vanadium sites. # These authors contributed equally to this work Industrial processes prominently feature π-acidic gases, and an adsorbent capable of selectively interacting with these molecules could enable a number of important chemical separations 1-4 . In nature, enzymes, and correspondingly their synthetic analogues, use accessible, reducing metal centers to bind and even activate weakly π-acidic species such as N 2 through backbonding interactions 5-7 , and incorporation of similar moieties into a porous material should give rise to a new mechanism of adsorption for these gaseous substrates 8 .However, synthetic challenges have prevented realization of such a material. Here, we report a metal-organic framework featuring exposed vanadium(II) centers with an electronic configuration and 3d-orbital energies conducive to the back-donation of electron density to weak π-acids, thereby enabling highly selective adsorption. This new adsorption mechanism, together with the presence of a high concentration of available adsorption sites, results in record N 2 capacities and selectivities for the removal of N 2 from mixtures with CH 4 , while further enabling the separation of olefins from paraffins at elevated temperatures.Ultimately, incorporating such π-basic metal centers into tunable porous materials offers a new handle for capturing and activating key molecular species within next-generation adsorbents.The implementation of adsorbent-based technology stands as a promising route toward mitigating the high energy and emission costs associated with current industrial chemical The synthesis of V 2 Cl 2.8 (

Purpose: The purpose of this randomized, double-blind study was to evaluate the efficacy of midazolam and propofol for postoperative sedation and early extubation following cardiac surgery. Methods: ASA physical status II-III patients scheduled to undergo elective first-time cardiac surgery with an ejec'uon fraction > 45% were eligible, All patients received a standardized sufentanilllsoflurane anaesthesia. During cardiopulmonary bypass I00 pg-kg-t.min z propofol was substituted for isoflurane, Upon arnval in the Intensr~e Care Unit (ICU), patients were randomized to either I0 pg.kg-l.min -i propofol (n = 21) or 0.25 pg-kg '.min ' midazolam (n = 20). Infusion rates were adjusted to maintain sedation within a predetermined range (Ramsay 2-4). The infusion was terminated after four hours. Patients were weaned from mechanical ventilation and their tracheas extubated when haemodynarnic stability, haemostasis, normothermia and mental orientation were confirmed. Haemodynamic measurements, arterial blood gas tensions and pulmonary function tests were recorded at specified times. Results: There were no differences between the two groups for the time spent at each level of sedation, number of infusion rate adjustments, amount of analgesic and vasoactive drugs, times to awakening and extubation. The costs of propofol were higher than those of midazolam. There were no differences in haemodynamic values, ar[enal blood gas tensions and pulmonary function. Conclusion: We conclude that midazolam and propofol are safe and effective sedative agents permitting early extubation in this selected cardiac patient population but propofol costs were higher.

We report the coordination chemistry of the tripodal tris[2-amido(2-pyridyl)ethyl]amine ligand, L, with thorium(iv) and uranium(iv). Using a salt-metathesis strategy from the potassium salt of this ligand, K3L, new actinide complexes were isolated, namely the dimeric thorium complex [ThCl(L)] (1) and the monomeric uranium complex UI(THF)(L) (2); under different crystallisation conditions, the dimeric uranium complex is also isolated, [UI(L)] (2-dimer). With the aim of studying electronic phenomena such as magnetic exchange between two actinide ions, we have synthesised the first examples of dinuclear, quinoid-bridged actinide complexes from dianionic 2,5-bis[2,6-(diisopropyl)anilide]-1,4-benzoquinone (QDipp) and 2,5-bis[2-(methoxy)anilide]-1,4-benzoquinone (QOMe) ligands. The resulting complexes are [Th(L)]Q (3), [Th(THF)(L)]Q (5) and [U(L)]Q (6). The targeted [U(L)]Q complex (4) could not be isolated. All isolated complexes have been characterised by spectroscopic methods and X-ray crystallography. The uranium(iv) complexes 2-dimer and 6 have been studied by SQUID magnetometry but indicate that there is negligible magnetic exchange between the two uranium(iv) ions. The reduced form of 6, [K(18-c-6)][6-] is unstable and highly sensitive, but X-ray crystallography indicates that it is a novel UU complex bridged by a quinoid-radical.