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Helen Stœcklievans - One of the best experts on this subject based on the ideXlab platform.
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metal framework degradation reactions of the mixed metal Cluster anions m3ir co 13 m ru os with bis diphenylphosphino methane and with tricyclohexylphosphine synthesis and structure of hru2ir co 5 dppm 3 hru2ir co 6 pcy3 3 h2os2ir2 co 10 pcy3 2 and h3os3ir co 8 pcy3 3
Polyhedron, 1999Co-Authors: Susanne Haak, Georg Sussfink, Antonia Neels, Helen StœcklievansAbstract:Abstract The mixed-metal Cluster anions [M3Ir(CO)13]− (M=Ru, Os) react in methanol under metal-framework degradation with bis(diphenylphosphino)methane (dppm) or tricyclohexylphosphine (PCy3) to give a series of neutral tri- and tetranuclear mixed-metal Clusters. The reaction of [M3Ir(CO)13]− (M=Ru, Os) with dppm leads to the phosphine-substituted hydrido derivatives HRu2Ir(CO)5(dppm)3 (1) and HOs2Ir(CO)5(dppm)3 (2), respectively. The two 48e Clusters show a triangular arrangement of the M2Ir skeleton. The dppm ligands are coordinated in bridging positions over each metal–metal edge; the hydride is bonded terminally to the iridium atom. Cluster degradation is also observed by treating [Ru3Ir(CO)13]− with PCy3 in methanol, giving the highly electron-deficient (44e) mixed-metal Cluster HRu2Ir(CO)6(PCy3)3 (3). The reaction of the osmium homologue [Os3Ir(CO)13]− with PCy3 under the same conditions leads to a mixture of the neutral tetranuclear Clusters H2Os2Ir2(CO)10(PCy3)2 (4) and H3Os3Ir(CO)8(PCy3)3 (5). Both Clusters, 4 and 5 still have a tetrahedral metal core like the Starting Cluster anion but in 4 an osmium atom has been replaced by an iridium atom. The molecular structures of 1, 3, 4 and 5 were confirmed by single-crystal X-ray structure analyses.
Susanne Haak - One of the best experts on this subject based on the ideXlab platform.
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metal framework degradation reactions of the mixed metal Cluster anions m3ir co 13 m ru os with bis diphenylphosphino methane and with tricyclohexylphosphine synthesis and structure of hru2ir co 5 dppm 3 hru2ir co 6 pcy3 3 h2os2ir2 co 10 pcy3 2 and h3os3ir co 8 pcy3 3
Polyhedron, 1999Co-Authors: Susanne Haak, Georg Sussfink, Antonia Neels, Helen StœcklievansAbstract:Abstract The mixed-metal Cluster anions [M3Ir(CO)13]− (M=Ru, Os) react in methanol under metal-framework degradation with bis(diphenylphosphino)methane (dppm) or tricyclohexylphosphine (PCy3) to give a series of neutral tri- and tetranuclear mixed-metal Clusters. The reaction of [M3Ir(CO)13]− (M=Ru, Os) with dppm leads to the phosphine-substituted hydrido derivatives HRu2Ir(CO)5(dppm)3 (1) and HOs2Ir(CO)5(dppm)3 (2), respectively. The two 48e Clusters show a triangular arrangement of the M2Ir skeleton. The dppm ligands are coordinated in bridging positions over each metal–metal edge; the hydride is bonded terminally to the iridium atom. Cluster degradation is also observed by treating [Ru3Ir(CO)13]− with PCy3 in methanol, giving the highly electron-deficient (44e) mixed-metal Cluster HRu2Ir(CO)6(PCy3)3 (3). The reaction of the osmium homologue [Os3Ir(CO)13]− with PCy3 under the same conditions leads to a mixture of the neutral tetranuclear Clusters H2Os2Ir2(CO)10(PCy3)2 (4) and H3Os3Ir(CO)8(PCy3)3 (5). Both Clusters, 4 and 5 still have a tetrahedral metal core like the Starting Cluster anion but in 4 an osmium atom has been replaced by an iridium atom. The molecular structures of 1, 3, 4 and 5 were confirmed by single-crystal X-ray structure analyses.
Antonia Neels - One of the best experts on this subject based on the ideXlab platform.
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metal framework degradation reactions of the mixed metal Cluster anions m3ir co 13 m ru os with bis diphenylphosphino methane and with tricyclohexylphosphine synthesis and structure of hru2ir co 5 dppm 3 hru2ir co 6 pcy3 3 h2os2ir2 co 10 pcy3 2 and h3os3ir co 8 pcy3 3
Polyhedron, 1999Co-Authors: Susanne Haak, Georg Sussfink, Antonia Neels, Helen StœcklievansAbstract:Abstract The mixed-metal Cluster anions [M3Ir(CO)13]− (M=Ru, Os) react in methanol under metal-framework degradation with bis(diphenylphosphino)methane (dppm) or tricyclohexylphosphine (PCy3) to give a series of neutral tri- and tetranuclear mixed-metal Clusters. The reaction of [M3Ir(CO)13]− (M=Ru, Os) with dppm leads to the phosphine-substituted hydrido derivatives HRu2Ir(CO)5(dppm)3 (1) and HOs2Ir(CO)5(dppm)3 (2), respectively. The two 48e Clusters show a triangular arrangement of the M2Ir skeleton. The dppm ligands are coordinated in bridging positions over each metal–metal edge; the hydride is bonded terminally to the iridium atom. Cluster degradation is also observed by treating [Ru3Ir(CO)13]− with PCy3 in methanol, giving the highly electron-deficient (44e) mixed-metal Cluster HRu2Ir(CO)6(PCy3)3 (3). The reaction of the osmium homologue [Os3Ir(CO)13]− with PCy3 under the same conditions leads to a mixture of the neutral tetranuclear Clusters H2Os2Ir2(CO)10(PCy3)2 (4) and H3Os3Ir(CO)8(PCy3)3 (5). Both Clusters, 4 and 5 still have a tetrahedral metal core like the Starting Cluster anion but in 4 an osmium atom has been replaced by an iridium atom. The molecular structures of 1, 3, 4 and 5 were confirmed by single-crystal X-ray structure analyses.
Georg Sussfink - One of the best experts on this subject based on the ideXlab platform.
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metal framework degradation reactions of the mixed metal Cluster anions m3ir co 13 m ru os with bis diphenylphosphino methane and with tricyclohexylphosphine synthesis and structure of hru2ir co 5 dppm 3 hru2ir co 6 pcy3 3 h2os2ir2 co 10 pcy3 2 and h3os3ir co 8 pcy3 3
Polyhedron, 1999Co-Authors: Susanne Haak, Georg Sussfink, Antonia Neels, Helen StœcklievansAbstract:Abstract The mixed-metal Cluster anions [M3Ir(CO)13]− (M=Ru, Os) react in methanol under metal-framework degradation with bis(diphenylphosphino)methane (dppm) or tricyclohexylphosphine (PCy3) to give a series of neutral tri- and tetranuclear mixed-metal Clusters. The reaction of [M3Ir(CO)13]− (M=Ru, Os) with dppm leads to the phosphine-substituted hydrido derivatives HRu2Ir(CO)5(dppm)3 (1) and HOs2Ir(CO)5(dppm)3 (2), respectively. The two 48e Clusters show a triangular arrangement of the M2Ir skeleton. The dppm ligands are coordinated in bridging positions over each metal–metal edge; the hydride is bonded terminally to the iridium atom. Cluster degradation is also observed by treating [Ru3Ir(CO)13]− with PCy3 in methanol, giving the highly electron-deficient (44e) mixed-metal Cluster HRu2Ir(CO)6(PCy3)3 (3). The reaction of the osmium homologue [Os3Ir(CO)13]− with PCy3 under the same conditions leads to a mixture of the neutral tetranuclear Clusters H2Os2Ir2(CO)10(PCy3)2 (4) and H3Os3Ir(CO)8(PCy3)3 (5). Both Clusters, 4 and 5 still have a tetrahedral metal core like the Starting Cluster anion but in 4 an osmium atom has been replaced by an iridium atom. The molecular structures of 1, 3, 4 and 5 were confirmed by single-crystal X-ray structure analyses.
Elizabeth Ayers - One of the best experts on this subject based on the ideXlab platform.
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skill set profile Clustering the empty k means algorithm with automatic specification of Starting Cluster centers
Educational Data Mining, 2010Co-Authors: Rebecca Nugent, Nema Dean, Elizabeth AyersAbstract:While students’ skill set profiles can be estimated with formal cognitive diagnosis models [8], their computational complexity makes simpler proxy skill estimates attractive [1, 4, 6]. These estimates can be Clustered to generate groups of similar students. Often hierarchical agglomerative Clustering or k-means Clustering is utilized, requiring, for K skills, the specification of 2^K Clusters. The number of skill set profiles/Clusters can quickly become computationally intractable. Moreover, not all profiles may be present in the population. We present a flexible version of k-means that allows for empty Clusters. We also specify a method to determine efficient Starting centers based on the Q-matrix. Combining the two substantially improves the Clustering results and allows for analysis of data sets previously thought impossible.