Structural and Bonding Patterns in Cluster Chemistry

Wade, Kenneth

doi:10.1016/s0065-2792(08)60027-8

Cited by 1,580 publications

(172 citation statements)

References 211 publications

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“…The nature of earlier theories can be illustrated by the discussion of one of them (20), as applied to the molecule Rh6(CO)16, which was described in the preceding paragraphs.…”

Section: Discussionmentioning

confidence: 99%

Structure of transition-metal cluster compounds: Use of an additional orbital resulting from the f, g character of spd bond orbitals

Pauling¹

1977

Proc. Natl. Acad. Sci. U.S.A.

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A general theory of the structure of complexes of the transition metals is developed on the basis of the enneacovalence of the metals and the requirements of the electroneutrality principle. An extra orbital may be provided through the small but not negligible amount of fand g character of spd bond orbitals, and an extra electron or electron air may be accepted in this orbital for a single metal or a c uster to neutralize the positive electric charge resulting from the partial ionic character of the bonds with ligands, suc-h as the carbonyl group. Examples of cluster compounds of cobalt, ruthenium, rhodium, osmium, and gold are discussed. The composition and structure of a great many compounds of transition metals correspond well to the assumption that transition-metal atoms can use their set of nine hybrid sp3d5 bond orbitals in forming bonds (1-4). For example, cobalt has nine outer electrons and accordingly can form nine bonds, as in the molecule hydridotetracarbonylcobalt, HCo(CO)4, in which a single bond is formed with a hydrogen atom and double bonds are formed with each of the four carbon atoms. Another example is the enneahydridorhenate anion, [ReHg]2-, in which the rhenium atom, which has increased its number of valence electrons from 7 to 9 by transfer of 2 from an electropositive metal (potassium in K2ReHg), forms single bonds with each of 9 hydrogen atoms. A few complexes are known, however, for which the composition and structure indicate that an additional stable orbital, which can serve as a bond orbital, is present. The explanation of this deviation from the predictions of the simple hybrid-orbital theory of chemical bonds has not been obvious. I have now found that consideration of the f, and to some extent the g, character of spd bond orbitals leads to the conclusion that some transition-metal atoms or clusters of them are provided with an additional bond orbital by the release of some spd character through the contribution of a small amount of f and g character by the relatively unstablef and g orbitals. Hybrid bond orbitalsIn the simple theory of hybrid bond orbitals (5, 6) the bond strength S, equal to the value of the angular part of the wave function in the bond direction, is taken as a measure of the bond-forming power of the orbital. The values of S for the best hybrid sp, spd, and spdf bond orbitals are 2, 3, and 4, respectively. The carbon atom is usually described as forming bonds in the four tetrahedral directions by using a set of four best Sp3 bond orbitals, each with strength 2. It has been pointed out, however, that the bond orbitals have some d and f character,The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 solely to indicate this fact. estimated at about 4 and 2%, respectively, which increases the value of S to about 2.76, thus making the bonds significantly stronger (ref. 6, p. 126). The spectral term values for potassium, rub...

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“…The nature of earlier theories can be illustrated by the discussion of one of them (20), as applied to the molecule Rh6(CO)16, which was described in the preceding paragraphs.…”

Section: Discussionmentioning

confidence: 99%

Structure of transition-metal cluster compounds: Use of an additional orbital resulting from the f, g character of spd bond orbitals

Pauling¹

1977

Proc. Natl. Acad. Sci. U.S.A.

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“…Octahedral [E 6 ] 2− clusters have been isolated only by an organometallic synthetic route as transition metalstabilized species [{EM(CO) 5 } 6 ] 2− (E = Ge, Sn; M = Cr, Mo, W) consisting of an almost perfect E 6 octahedron with each E atom coordinated to an M(CO) 5 fragment, as shown for the first time for E = Sn and M = Cr (Schiemenz & Huttner 1993). However, the anion [{SnCr(CO) 5 } 6 ] 2− was produced when Na 2 [Cr 2 (CO) 10 ] was treated with SnCl 2 in the presence of bipy (bipy = 2,2 -bipyridine) (Kircher et al 1998) (Wade 1976). Each group 14 atom possesses four valence electrons, two of which remain as one 'lone pair' at each vertex equivalent to the covalent exo-BH bonds in boranes.…”

Section: Homoatomic Clusters Of Tetrel Elements (A) Brief Review Of Hmentioning

confidence: 92%

Polyhedral nine-atom clusters of tetrel elements and intermetalloid derivatives

Scharfe

Fässler

2010

Phil. Trans. R. Soc. A.

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Homoatomic polyanions have the basic capability for a bottom-up synthesis of nanostructured materials. Therefore, the chemistry and the structures of polyhedral nine-atom clusters of tetrel elements [E 9 ] 4− is highlighted. The nine-atom Zintl ions are available in good quantities for E = Si-Pb as binary alkali metal (A) phases of the composition A 4 E 9 or A 12 E 17 . Dissolution or extraction of the neat solids with aprotic solvents and crystallization with alkali metal-sequestering molecules or crown ethers leads to a large variety of structures containing homoatomic clusters with up to 45 E atoms. Cluster growth occurs via oxidative coupling reactions. The clusters can further act as a donor ligand in transition metal complexes, which is a first step to the formation of bimetallic clusters. The structures and some nuclear magnetic resonance spectroscopic properties of these so-called intermetalloid clusters are reviewed, with special emphasis on tetrel clusters that are endohedrally filled with transition metal atoms.

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“…The existence of cluster series was also detected and implied through the work of Wade (Wade, 1976), Mingos (Mingos, 1987) and the correlation of cluster symmetries by Rudolph (Rudolph, 1976). This is confirmed by the current work of applying skeletal numbers derived from the 4n series method (Kiremire, 2015b) which clearly indicate the existence of a whole vast universe of clusters linking up naked metallic elements to metal carbonyls (Kiremire, 2016b), metalloboranes (Kiremire, 2016c), Zintyl ions (Kiremire, 2016d), carboranes and other heteroboranes, boranes, and main group element clusters (Kiremire, 2017c).…”

Section: Brief Backgroundmentioning

confidence: 95%

“…The recently published excellent article by Alan Welch outlines the historical development of chemical clusters (Welch, 2013).The major highlights include STYX numbers (Lipscomb, 1963), Wade"s rules (Wade, 1971(Wade, , 1976), Mingo"s rules (Mingos, 1972(Mingos, , 1984(Mingos, , 1987), Rudolph"s symmetry correlation system (Rudolph, 1976) and Jemmis research group work (Jemmis, 2005(Jemmis, , 2006(Jemmis, , 2008 among others. The current 4n series method being utilized to analyze clusters was developed by the identification of a simple pattern within clusters (Kiremire, 2014(Kiremire, , 2015(Kiremire, , 2016.…”

Section: Introductionmentioning

confidence: 99%

Graph Theory of Chemical Series and Broad Categorization of Clusters

Kiremire¹

2018

IJC

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The recent introduction of skeletal numbers has made it much easier to analyze and categorize a wide range of many chemical clusters. In the process, it has been found that a large number of transition metal clusters with and without ligands are capped and do possess closo nuclear clusters. On the basis of the nuclear index, the clusters have been categorized into groups. The categorization of the clusters will greatly assist in promoting deeper understanding and the synthesis of novel clusters and their applications. A simple concept of graph theory of capping clusters has been introduced.

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Structural and Bonding Patterns in Cluster Chemistry

Cited by 1,580 publications

References 211 publications

Structure of transition-metal cluster compounds: Use of an additional orbital resulting from the f, g character of spd bond orbitals

Structure of transition-metal cluster compounds: Use of an additional orbital resulting from the f, g character of spd bond orbitals

Polyhedral nine-atom clusters of tetrel elements and intermetalloid derivatives

Graph Theory of Chemical Series and Broad Categorization of Clusters

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