Long-term absolute gravity monitoring has a wide range of applications in the field of geodesy, geophysics, seismology, volcanology, hydrology, etc. The traditional method of long-term absolute gravity monitoring is realized by the combination of absolute gravimeter and relative gravimeter. Here we report on a new type of compact gravimeter based on atom interferometry used for long-term absolute gravity measurements. The long-term absolute gravity monitoring could be carried out with only a single instrument. Over the course of a month we took long-term absolute gravity measurements in a seismic station. With an interrogation time of 120 ms and a repetition rate of 2 Hz, the sensitivity of our cold atom gravimeter reaches 300 µGal √ Hz −1 without any vibration isolation system, and the gravity residual fluctuations are within ±60 µGal.

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In the past decades, Multi-component reactions (MCRs) have been shown to be powerful tools for the synthesis of biologically active compounds and drug candidates from simple and readily accessible starting materials. 1 They offer significant advantages over conventional synthetic strategies by shortening reaction time, reducing waste, saving energy and making full use of starting materials. [2][3][4] Furthermore, the design of MCRs for the development of efficient chemical syntheses of complex and high added value molecules is another attractive area in chemistry. [5][6][7] Naphthoquinone derivatives particularly 3-substituted-2-hydroxy-1,4-naphthoquinones are of much importance because this fragment is a key moiety in numerous biologically active compounds. 8 For example as showed in the figure 1, atovaquone, lapachol, parvaquone and buparvaquone (Figure 1, first row) exhibit antimalarial, antibacterial, antiprotozoal, antitumor activities. 9 Similarly, pyrazolone framework is a well-known heterocycle in many drug substances of medicinal fields. To list some pyrazolone derivatives ( figure 1, seond row) such as antipyrine (phenazone), 4-aminopyrine (aminophenazone), metamizol (novalgin), and 4-isopropylpyrine (propyphenazone) are all useful antipyretic and analgesic drugs. 10 Pyrazolone derivatives also have ubiquitous applications in the development of acaricides, dyes, fungicides, herbicides, insecticides, inhibitors and reagents. [11][12][13][14][15][16][17] It is promising that the integration of these two bioactive units into a single molecule may exhibit new or improved pharmacological properties.Considering the above points, and also in continuation of our interest on the synthesis of different kinds of heterocyclic compounds based on MCRs. [18][19][20][21][22][23][24][25] Herein we wish to report MgCl 2 as a low-toxic catalyst for one-pot synthesis of 2-hydroxy-3-((5-methyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)(phenyl)methyl)naphthalene-1,4-dione

A scandium dication active species [(IPr)­Sc­(μ-CH2SiMe3)­(μ-CH2CHMe2)­Al i Bu2]2+[B­(C6F5)4]2 – (IPr = (2,6-C6H3 i Pr2NCH)2C) in situ generated from the reaction of an N-heterocyclic carbene-ligated scandium trialkyl complex (IPr)­Sc­(CH2SiMe3)3 (2) with 1–3 equiv of cocatalyst [Ph3C]­[B­(C6F5)4] and an excess of Al i Bu3 exhibits unprecedentedly high activity (up to 2.2 × 106 g·molSc –1·h–1) and syndiotactic selectivity (rrrr > 99%) in the polymerization of o-methoxystyrene (oMOS) and its silyloxy- or fluorine-substituted derivatives, affording syndiotactic poly­(oMOS)­s and their silyloxy or fluorine-substituted derivatives with ultrahigh molecular weight (M n up to 4.6 × 106) and moderate molecular weight distributions (M w/M n = 1.37–2.21) unavailable by the traditional catalysts. Based on in situ NMR spectroscopy, matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) spectroscopy, and density functional theory (DFT) calculations, a plausible coordination polymerization mechanism has been proposed for the syndiotactic polymerization of oMOS by such a Sc dication active species.