Electronic structure of triple-decker sandwich compounds with P5, P6, As5, and CnHn as middle rings

Direct insertion of sulfur, selenium and tellurium atoms into metallaborane cages using chalcogen powders

“…1) and a short cross cage Mo-Mo bond (2.665(2) Å). Alternatively, as the available cluster bonding electrons of 6 are insufficient to meet the requirements of single eight-vertex nido-geometry, it could be better described as 26 valence electron (ve) triple-decker complex [47][48][49][50]. In addition, 6 is isoelectronic to those of arene-bridged-[(g 5 -C 5 H 5 V) 2 (l-g 6 :g 6 -C 6 H 6 )] [51], triple-decker sandwich complexes, for example, [(g 5 -C 5 Me 4 EtV) 2 (l-g 6 :g 6 -P 6 )] [52] and [(g 5 -C 5 H 3 t Bu 2 Nb) 2 (l-g 6 :g 6 -P 6 )] [53], and closo-[(g 5 -C 5 Me 5 W) 2 B 6 H 10 ] [54].…”

Synthesis of [(Cp*Re)2BnHn]n=8-10: Metal Boride Particles That Stretch the Cluster Structure Paradigms

“…These compounds are triple-decker complexes [27] and they provide insight on the electronic origin of the shapes observed. Comparing 9 sep [(Cp*Rh) 2 (m-h 6 :h 6 -C 4 H 4 B 2 Me 2 )] 2 [28] with 6 sep [{Cp*Re) 2 (m-h 6 :h 6 -B 6 H 6 )] shows that as the Cp*M fragments are moved within bonding distance three orbitals, which are filled in the 9 sep compound, are emptied and a substantial HOMO ± LUMO gap is produced for 6 sep. [29] Likewise, the generation of the observed structure of [(Cp*Re) 2 B 7 H 7 ] from the canonical tricapped trigonal prismatic geometry causes three orbitals to rise sufficiently high in energy to become unoccupied. [15,30] As with the triple-decker complexes, these molecular orbitals consist of an ReRe antibonding orbital and two ReB orbitals that are boron-ring ± metal d antibonding.…”

Triple-decker transition metal complexes bridged by a single carbocyclic ring

“…The related complexes 19b,c were prepared by arene exchange of 19a at high temperatures in the appropriate aromatic solvent (toluene or mesitylene, respectively); 19d (isopropylbenzene bridge) is a byproduct of the synthesis of 19a [26]. These paramagnetic 26VE complexes do not obey the 30/34VE rule of Hoffmann et al [30] but it has been shown that this rule does not in fact apply to complexes of the electron-poor early transition metals [31,32].…”

“…Molecular orbital schemes for (a) {Cp 3 Ni 2 } +[30]; (b) trans-(CpV) 2 (l-g 6 :g 6 -C 6 H 6 )[31]. Vertical energy scales are arbitrary; not drawn to scale.…”