Posts Tagged ‘Ligand’
Saturday, May 6th, 2017
Mention carbon dioxide (CO2) to most chemists and its properties as a metal ligand are not the first aspect that springs to mind. Here thought I might take a look at how it might act as such.
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Tags:Carbon, Carbon Capture & Storage, carbon dioxide, chemical bonding, Chemistry, Environment, Ligand, ligand-metal coordination, metal, metal ligand, Propellants, Search queries, search query, short metal-centroid distance
Posted in crystal_structure_mining | 2 Comments »
Sunday, September 11th, 2016
To quote from Wikipedia: in chemistry, a carbene is a molecule containing a neutral carbon atom with a valence of two and two unshared valence electrons. The most ubiquitous type of carbene of recent times is the one shown below as 1, often referred to as a resonance stabilised or persistent carbene. This type is of interest because of its ability to act as a ligand to an astonishingly wide variety of metals, with many of the resulting complexes being important catalysts. The Wiki page on persistent carbenes shows them throughout in form 1 below, thus reinforcing the belief that they have a valence of two and by implication six (2×2 shared + 2 unshared) electrons in the valence shell of carbon. Here I consider whether this name is really appropriate.
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Tags:Carbenes, chemical bonding, energy barrier, free energy, Functional groups, Ligand, Mesoionic carbene, Organometallic chemistry, Persistent carbene, quantum mechanical solution, Reactive intermediates, Transition metal carbene complex, Valence, Valence electron
Posted in crystal_structure_mining, General | No Comments »
Monday, May 30th, 2016
This is a follow-up to one aspect of the previous two posts dealing with nucleophilic substitution reactions at silicon. Here I look at the geometries of 5-coordinate compounds containing as a central atom 4A = Si, Ge, Sn, Pb and of the specific formula C34AO2 with a trigonal bipyramidal geometry. This search arose because of a casual comment I made in the earlier post regarding possible cooperative effects between the two axial ligands (the ones with an angle of ~180 degrees subtended at silicon). Perhaps the geometries might expand upon this comment?
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Tags:Anomer, Anomeric effect, Carbohydrate chemistry, Carbohydrates, Ligand, Molecular geometry, Physical organic chemistry, Stereochemistry, Stereoelectronic effect, Trigonal bipyramidal molecular geometry
Posted in Chemical IT, crystal_structure_mining | 3 Comments »
Sunday, September 6th, 2015
An article entitled "Four Decades of the Chemistry of Planar Hypercoordinate Compounds"[cite]10.1002/anie.201410407[/cite] was recently reviewed by Steve Bacharach on his blog, where you can also see comments. Given the recent crystallographic themes here, I thought I might try a search of the CSD (Cambridge structure database) to see whether anything interesting might emerge for tetracoordinate carbon.
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Tags:Angle, Cambridge, chemical bonding, Cycloalkane, Cyclopropane, HTML, HTML element, Ligand, metal, search definition, search results, search software, Steve Bacharach
Posted in Chemical IT, crystal_structure_mining | No Comments »