The new series of tellurium-containing trigonal bipyramidal clusters [Te2CrM2(CO)10]2-
(M = Cr, 2a; Mo, 2b; W, 2c) has been synthesized from the ring closure reactions of the ring
complexes [Te2Cr2M2(CO)18]2- (M = Cr, 1a; Mo, 1b; W, 1c) in refluxing acetone solutions.
The mixed-metal ring complexes [Te2Cr2M2(CO)18]2- (M = Mo, 1b; M = W, 1c) can be obtained
readily from the metal expansion reactions of the dichromium complex [Te{Cr(CO)5}2]2- with
M(CO)6 (M = Mo, W) in MeCN. The ring complexes [Te2Cr2M2(CO)18]2- (M = Mo, 1b; W, 1c)
each display a Te2M2 ring with each Te atom externally coordinated with one Cr(CO)5 group,
while the new group 6-containing trigonal bipyramidal clusters [Te2CrM2(CO)10]2- (M = Cr,
2a; Mo, 2b; W, 2c) each consist of a CrM2 trigonal plane capped above and below by two
tellurides. Complexes 1b−2c are fully characterized by IR, 125Te NMR spectroscopy, and
single-crystal X-ray analysis. This paper describes a new methodology to the highly strained
group 6 metal clusters [Te2CrM2(CO)10]2- (M = Cr, 2a; Mo, 2b; W, 2c) from the ring closure
reactions of their corresponding ring complexes [Te2Cr2M2(CO)18]2- (M = Cr, 1a; Mo, 1b; W,
1c), and the interesting transformations and structural features of the new complexes 1b−2c are systematically studied as well.
Midstream of the Keelung River Basin in Northern Taiwan has become highly urbanized and densely populated area. Flood inundation along riversides frequently occurred during typhoons or rainstorms. Three protection measures, including constructions of highlevel protection levees, a diversion channel, and a detention reservoir, were proposed for flood mitigation. The main purpose of this study is to evaluate the flood mitigation performance of the three proposed structural measures by using combined hydrologic analyses and hydraulic routings. A semi-distributed parallel-type linear reservoirs rainfall-runoff model was used for estimating the surface runoff. Furthermore, a 1-D dynamic channel routing model was coupled with a two-dimensional inundation model to simulate the hydraulic characteristics of river flooding and overland flow. Simulation results of flood stages, runoff peak discharges, and inundation extent under design rainfall scenarios were chosen as the criteria for evaluation. The results showed a diversion channel is superior to the other two measures for flood mitigation of the study area. After the process of environmental impact assessment, a revised diversion channel approach has been approved for construction as the major structural measure.
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