Measure of the steric bulk of a ligand in a coordination complex
Ligand cone angle shows how much space is taken up by a ligand coordinated to a metal center.
In coordination chemistry, the ligand cone angle (θ) is a measure of the steric bulk of a ligand in a transition metal coordination complex. It is defined as the solid angle formed with the metal at the vertex of a cone and the outermost edge of the van der Waals spheres of the ligand atoms at the perimeter of the base of the cone. Tertiary phosphine ligands are commonly classified using this parameter, but the method can be applied to any ligand. The term cone angle was first introduced by Chadwick A. Tolman, a research chemist at DuPont. Tolman originally developed the method for phosphine ligands in nickel complexes, determining them from measurements of accurate physical models.[1][2][3]
^Tolman, Chadwick A. (1970-05-01). "Phosphorus ligand exchange equilibriums on zerovalent nickel. Dominant role for steric effects". J. Am. Chem. Soc.92 (10): 2956–2965. doi:10.1021/ja00713a007.
^Tolman, C. A.; Seidel, W. C.; Gosser, L. W. (1974-01-01). "Formation of three-coordinate nickel(0) complexes by phosphorus ligand dissociation from NiL4". J. Am. Chem. Soc. 96 (1): 53–60. doi:10.1021/ja00808a009.
^Tolman, C. A. (1977). "Steric Effects of Phosphorus Ligands in Organometallic Chemistry and Homogeneous Catalysis". Chem. Rev.77 (3): 313–48. doi:10.1021/cr60307a002.
the ligandconeangle (θ) is a measure of the steric bulk of a ligand in a transition metal coordination complex. It is defined as the solid angle formed...
usually not useful. Ligandconeangles are measures of the size of ligands in coordination chemistry. It is defined as the solid angle formed with the metal...
boundary element method (BEM) Evaluating the size of ligands in metal complexes, see ligandconeangle Calculating the electric field and magnetic field...
high basicity (pKa = 9.7) and a large ligandconeangle (170°). Important complexes containing P(Cy)3 ligands include the 2005 Nobel Prize-winning Grubbs'...
donated to the metal (denticity or hapticity). The size of a ligand is indicated by its coneangle. The composition of coordination complexes have been known...
This ligand is one of the most basic alkyl phosphines with a large ligandconeangle of 160. Pi-Pr3 is similar to the more frequently used tricyclohexylphosphine...
The ligandconeangle (θ) is the apex angle of a cylindrical cone, which is centered 2.28 Å from the center of the P atom. However, the coneangle of an...
between the two ligands. Compared to phosphine ligands, NHC ligands' coneangle is more complex. The imidazole ring of the NHC ligand is angled away from the...
second coordination sphere for metal complexes. Coordination number Ligandconeangle Coordination geometry What Is A Coordination Compound? Zhao, Meng;...
coordination chemistry, the bite angle is the angle on a central atom between two bonds to a bidentate ligand. This ligand–metal–ligand geometric parameter is used...
EtCage complexes are known, since the ligand is highly basic (for a phosphite) and has a small ligandconeangle (101°). Illustrative complexes include...
If the plane intersects both halves of the double cone but does not pass through the apex of the cones, then the conic is a hyperbola. Besides being a conic...
Triethylphosphine is a highly basic ligand that forms coordination complexes with many metals. As a ligand, triethylphosphine's Tolman coneangle is 132°. Being a relatively...
a highly basic ligand that forms complexes with most metals. As a ligand, trimethylphosphine's Tolman coneangle is 118°. This angle is an indication...
carbene (NHC) ligands have been ranked according to IR data recorded on cis-[RhCl(NHC)(CO)2] complexes. Metal carbonyl Tolman coneangle Robert H. Crabtree...
methylphosphonate: P(OCH3)3 → CH3P(O)(OCH3)2 As a ligand, trimethyl phosphite has a smaller coneangle and better acceptor properties relative to trimethylphosphine...
groups is significantly larger reductions in the contact angle upon oxidation. Josiphos ligands International Union of Pure and Applied Chemistry (2014)...
Tolman developed his “ligandconeangle” theory that developed into the widely accepted electronic and steric effects of ligands on inorganic and organometallic...
that help cell-cell and cell-extracellular matrix (ECM) adhesion. Upon ligand binding, integrins activate signal transduction pathways that mediate cellular...
by tert-butyl groups. When used as ligands, the steric bulk of tertiary phosphines is evaluated by their coneangle. The barrier to pyramidal inversion...
interpreted and can mask signals for other ligands. Compared to other tertiary phosphines, it is compact (coneangle: 136°) and basic (χ-parameter: 5.25 cm−1)...
cubane-type cluster. Related bulky anionic ligands include C5Me5−, (Me3Si)2N−, and NacNac−. Silox has a larger coneangle than C5Me5− and is a poorer donor. It...
ISSN 0002-7863. Seligson, Allen L.; Trogler, William C. (March 1991). "Coneangles for amine ligands. X-ray crystal structures and equilibrium measurements for ammonia...
ligands. Metal bound t-Bu3PN− has a coneangle of 87° vs 83 for cylclopentadienyl. Compared to Cp, the bulky substituents of the phosphinimide ligand...
similarly to those of CO. Because the CNC linkage is linear, the coneangle of these ligands is small, so it is easy to prepare polyisocyanide complexes....
transition metals of groups 7–10. In terms of steric bulk, PPh3 has a Tolman coneangle of 145°, which is intermediate between those of P(C6H11)3 (170°) and P(CH3)3...
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