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We present an overview of the National Science Foundation’s Daniel K. Inouye Solar Telescope (DKIST), its instruments, and support facilities. The 4 m aperture DKIST provides the highest-resolution observations of the Sun ever achieved. The large aperture of DKIST combined with state-of-the-art instrumentation provide the sensitivity to measure the vector magnetic field in the chromosphere and in the faint corona, i.e. for the first time with DKIST we will be able to measure and study the most important free-energy source in the outer solar atmosphere – the coronal magnetic field. Over its operational lifetime DKIST will advance our knowledge of fundamental astronomical processes, including highly dynamic solar eruptions that are at the source of space-weather events that impact our technological society. Design and construction of DKIST took over two decades. DKIST implements a fast (f/2), off-axis Gregorian optical design. The maximum available field-of-view is 5 arcmin. A complex thermal-control system was implemented in order to remove at prime focus the majority of the 13 kW collected by the primary mirror and to keep optical surfaces and structures at ambient temperature, thus avoiding self-induced local seeing. A high-order adaptive-optics system with 1600 actuators corrects atmospheric seeing enabling diffraction limited imaging and spectroscopy. Five instruments, four of which are polarimeters, provide powerful diagnostic capability over a broad wavelength range covering the visible, near-infrared, and mid-infrared spectrum. New polarization-calibration strategies were developed to achieve the stringent polarization accuracy requirement of 5×10−4. Instruments can be combined and operated simultaneously in order to obtain a maximum of observational information. Observing time on DKIST is allocated through an open, merit-based proposal process. DKIST will be operated primarily in “service mode” and is expected to on average produce 3 PB of raw data per year. A newly developed data center located at the NSO Headquarters in Boulder will initially serve fully calibrated data to the international users community. Higher-level data products, such as physical parameters obtained from inversions of spectro-polarimetric data will be added as resources allow.

Starting from sodium carbomethoxycyclopentadienide, diphenylacetylene, and chlorotris(triphenylphosphine)cobalt(I), the title compound was obtained in four steps and 47% overall yield. On reaction with Pd(OAc) 2 , a single cyclopalladated diastereoisomer of (S)-( p R) configuration was isolated in 72% yield.

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Reaction of 1,3-dicyanobenzene with β-amino alcohols (S)-H 2 NCHRCH 2 OH (R ) i Pr, i Bu, t Bu, CH 2 Cy, CH 2 Ph) and (R)-H 2 NCHPhCH 2 OH gave new 1,3-bis(2′-oxazolinyl)benzenes (30-51%). These, together with 1,3-bis(4′,4′-dimethyl-2′-oxazolinyl)benzene, were treated with LDA/TMEDA followed by the addition of PdBr 2 (1,5-COD) to give [2,6-bis(2′-oxazolinyl)phenyl]palladium(II) bromide complexes (21-41%). In two cases no complexes were obtained (R ) Ph, CH 2 Ph) due to ring opening of the oxazolines by LDA/TMEDA. Treatment of the palladium complexes with AgBF 4 , AgOTf, or AgSbF 6 in wet CH 2 Cl 2 provided a series of cationic [2,6-bis(2′-oxazolinyl)phenyl]palladium complexes (28-87%) containing water coordinated to palladium, as established by an X-ray crystal structure analysis of (S,S)-[2,6bis(4′-isopropyl-2′-oxazolinyl)phenyl]aquopalladium(II) trifluoromethanesulfonate. All of the cationic complexes proved to be efficient catalysts for the Michael reaction between R-cyanocarboxylates and methyl vinyl ketone and between acrylonitrile and activated Michael donors. Selectivities of up to 34% ee were obtained for the formation of (R)-ethyl 2-cyano-2-methyl-5-oxohexanoate.