Steric effects in metal cluster compounds

Mingos, D. M. P.

doi:10.1021/ic00131a094

Cited by 67 publications

(28 citation statements)

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“…[15] Based on the Tolmans cone angle concept, Mingos developed am ethod to assess the cluster cone angle. [16] The cone angles of other ligands including isocyanides have also been reported. [17] In view of the multinuclear nature of Cu I alkynyl clusters, the bridging mode of alkynyl ligands,a nd the difference in geometries between phosphine and alkynyl ligands,t here is no universally applicable method for the cone angle determination of Cu I alkynyl systems.A nalogous to Mingos cluster cone angle definition, we estimated the cone angles by setting the apex of the cone in the center of the metal core polyhedron.…”

Section: Angewandte Chemiementioning

confidence: 97%

From Cluster to Polymer: Ligand Cone Angle Controlled Syntheses and Structures of Copper(I) Alkynyl Complexes

et al. 2016

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Copper(I) alkynyl complexes have attracted tremendous attention in structural studies, as luminescent materials, and in catalysis, and homoleptic complexes have been reported to form polymers or large clusters. Herein, six unprecedented structures of Cu(I) alkynyl complexes and a procedure to measure the cone angles of alkynyl ligands based on the crystal structures of these complexes are reported. An increase of the alkynyl cone angle in the complexes leads to a modulation of the structures from polymeric [((PhC≡CC≡C)Cu)2 (NH3 )]∞ , to a large cluster [(TripC≡CC≡C)Cu]20 (MeCN)4 , to a relatively small cluster [(TripC≡C)Cu]8 (Trip=2,4,6-iPr3 -C6 H2 ). The complexes exhibit yellow-to-red phosphorescence at ambient temperature in the solid state and the luminescence behavior of the Cu20 cluster is sensitive to acetonitrile.

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Section: Angewandte Chemiementioning

confidence: 97%

From Cluster to Polymer: Ligand Cone Angle Controlled Syntheses and Structures of Copper(I) Alkynyl Complexes

et al. 2016

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“…The exception to this trend, phenylethanethiol, is easily rationalized as a more sterically demanding ligand which, by virtue of its branched nature, provides a larger ‘cluster cone angle’ 34 relative to its length, when compared to straight chain alkanethiols. We expect that branched alkanethiols may also show increased stability relative to absolute chain length.…”

Section: Resultsmentioning

confidence: 99%

Practical stability of Au₂₅(SR)₁₈^−1/0/+1

et al. 2017

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Superatom electron shell and/or geometric shell filling underlies the thermodynamic stability of coinage and alkali metal clusters in both theoretical and experimental results. Factors beyond simple shell filling contribute substantially to the lifetime of ligated clusters in solution. Such factors include the nature of the solvent, the atmosphere and the steric size of the ligand shell. Here we systematically lay out a ‘practical’ stability model for ligated metal clusters, which includes both shell-closing aspects and colloidal stability aspects. Cluster decomposition may follow either fusion or fission pathways. Solvent polarity can be determinative of the decomposition pathway.

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“…“Cage cone angles” (i.e. the cluster cone angle8 concept applied in this case to a coordination cage) give a rough comparison of the different ligand sizes, even though the shape of L1 is rather irregular. They were estimated for the two ligands by taking the included Sb centre as the cage centroid, and representative angles to the outermost diametrically opposed atoms in the ligands.…”

Section: Resultsmentioning

confidence: 99%

Polar Self‐Assembly: Steric Effects Leading to Polar Mixed‐Ligand Coordination Cages

Zhang

Miller

Nieuwenhuyzen

et al. 2006

Chemistry A European J

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We present a highly unusual example of self-assembly, specifically a polar, mixed-ligand cage which forms in preference to symmetrical homo-ligand products, and which suggests that steric effects can be exploited to obtain novel non-uniform polyhedral cages. In particular, reaction between the bulky tripodal triphosphine 2,4,6-tris(diphenylphosphino)triazine, L1, the non-bulky tripodal trinitrile 2,4,6-tris(cyanomethyl)trimethylbenzene, L2 and silver hexafluoroantimonate, AgSbF6, in a 3:1:4 ratio gives the mixed-ligand aggregate [Ag4(L1)3(L2)(SbF6)]3+, 1-SbF6, instantly as the only product in quantitative yield. The X-ray crystal structure of complex 1-SbF6 is consistent with the suspected solution-state structure. The cage derives from trigonal-pyramidal geometry, the basal vertices of which are defined by three bulky triphosphines, L1, and the apical vertex by the non-bulky trinitrile, L2. There is apical elongation amounting to 19% in comparison to the ideal uniform tetrahedron. The cage also encapsulates an SbF6 anion. 19F NMR spectra in solution for the analogous PF6 complex [Ag4(L1)3(L2)(PF6)]3+, 1-PF6, confirm that one anion is also encapsulated in solution. The synthesis of the analogous CF3SO3(-) complex, [Ag4(L1)3(L2)(OTf)]3+, 1-OTf, in solution is also described, although 1-PF6 and 1-OTf could not be isolated due to slow decomposition in solution. The selective formation of these mixed-ligand cages is discussed in terms of ligand-ligand and ligand-included anion steric repulsions, which we propose prevent the formation of the competing hypothetical homo-ligand tetrahedral structure [Ag4(L1)4(SbF6)]3+, and thus favour the mixed ligand cage. "Cage cone angles" for L1 and L2 are estimated at 115 degrees and 101 degrees, respectively. Variable-temperature 31P NMR spectroscopy shows that complex 1-SbF6 and the related previously reported partial tetrahedral complex [Ag4(L1)3(anion)]3+ undergo dynamic twisting processes in solution between enantiomeric C3-symmetry conformations.

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Steric effects in metal cluster compounds

Cited by 67 publications

References 0 publications

From Cluster to Polymer: Ligand Cone Angle Controlled Syntheses and Structures of Copper(I) Alkynyl Complexes

From Cluster to Polymer: Ligand Cone Angle Controlled Syntheses and Structures of Copper(I) Alkynyl Complexes

Practical stability of Au₂₅(SR)₁₈^−1/0/+1

Polar Self‐Assembly: Steric Effects Leading to Polar Mixed‐Ligand Coordination Cages

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Steric effects in metal cluster compounds

Cited by 67 publications

References 0 publications

From Cluster to Polymer: Ligand Cone Angle Controlled Syntheses and Structures of Copper(I) Alkynyl Complexes

From Cluster to Polymer: Ligand Cone Angle Controlled Syntheses and Structures of Copper(I) Alkynyl Complexes

Practical stability of Au25(SR)18−1/0/+1

Polar Self‐Assembly: Steric Effects Leading to Polar Mixed‐Ligand Coordination Cages

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Practical stability of Au₂₅(SR)₁₈^−1/0/+1