Electron configuration metal clusters

A 98-electron, 7-metal cluster is two electrons short of a closo configuration. The structure would be expected to be a capped closo, such as the 98-electron species [Rh7(CO)i6] and Os7(CO)2i in Table 15-13. 

As discussed in Sec. 1.28.3.1, the number of Ph3PAu(0) groups in the hetero-nuclear clusters of the type [M(CO)x(AuPPh3), ] is determined by the electronic demand of the transition metal M, that requires a stable 18 electron configuration. The cluster cation [Pt(dppe)(AuPPh3)4] + is an exception to this rule, since the central Pt atom only achieves 16 electrons by adding to the 10 d electrons of the Pt(0) atom the four electrons of the two Pt P bonds, and the two electrons of the... 

In coating fullerenes with alkali metals, the stability of the cluster seemed to be determined primarily by the electronic configuration. The units C qM and C7oMg, where M is any alkali metal, proved to be exceptionally stable cluster building blocks. Coating a fullerene with more than 7 alkali metal atoms led to an even-odd alternation in the mass spectra, inter-... 

Slovokhotov, Yu.L. and Struchkov, Yu.T (1984) X-ray crystal structure of a distorted tetrahedral cluster in the salt [(Ph P)4Au4N] BF4 . Geometrical indication of stable electronic configurations in post-transition metal complexes and the magic number 18-e in centred gold clusters. Journal of Organometallic Chemistry, 177, 143-146. 

Interestingly, compounds of Class A or Class B have 50 cluster valence electrons if the three metal atoms are individually to have 18-electron configurations. Several of the compounds meet this requirement, e.g. (25), (27), (31) (34) or (36). However, compound (23) with 46 clusterValence ... 

Wade expanded the 1971 hypothesis to incorporate metal hydrocarbon 7T complexes, electron-rich aromatic ring systems, and aspects of transition metal cluster compounds [a parallel that had previously been noted by Corbett 19) for cationic bismuth clusters]. Rudolph and Pretzer chose to emphasize the redox nature of the closo, nido, and arachno interconversions within a given size framework, and based the attendant opening of the deltahedron after reduction (diagonally downward from left to right in Fig. 1) on first- and second-order Jahn-Teller distortions 115, 123). Rudolph and Pretzer have also successfully utilized the author s approach to predict the most stable configuration of SB9H9 (1-25) 115) and other thiaboranes. 

There are several prerequisites which have to be fulfilled for the one electron ECP approach to be applicable. In the case of metal clusters the atomic configuration must be known, i.e. one must safely be able to assume a dns2 or a drL+1s1 configurations on the atoms in the cluster. The d orbitals should not form covalent bonds neither within the cluster nor between the cluster and the adsorbate. Ferromagnetic metals and copper are likely to have these properties. For other metals this is not so clear. Indications are that e.g. the ground state of the Pts cluster is low spin with developed covalent intra cluster d-d bonds[22]. 

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