Molecular Alloys: Experimental and Theoretical Investigations on the Substitution of Zinc by Cadmium and Mercury in the Homologous Series [Mo(M ' R)(12)] and [M(M ' R)(8)] (M = Pd, Pt; M ' = Zn, Cd, Hg)

作者：Bollermann Timo; Cadenbach Thomas; Gemel Christian; von Hopffgarten Moritz; Frenking Gernot^*; Fischer Roland A

来源：Chemistry - A European Journal, 2010, 16(45): 13372-13384.

DOI：10.1002/chem.201001650

• bonding analysis
• cadmium
• cluster compounds
• coordination compounds
• zinc

The synthesis and structural characterization of novel, metal-rich, highly coordinated compounds [Mo(M'R)(12)] and [M(M'R)(8)] (M: Pd, Pt, Mo; M': Zn, Cd; R: Me= CH3, Cp*= pentamethylcyclopentadienyl) are reported. Additionally, a description of the bonding situation of the new compounds by means of quantum-chemical calculations is presented including the Hg analogues. Reaction of [Pt(GaCp*)(4)] with CdMe2 results in the formation of the unprecedented all-Cd coordinated [Pt(CdMe)(4)(CdCp*)(4)] (1). Similarly, the treatment of the all-Zn coordinated [Pd(ZnMe)(4)(ZnCp*)(4)] with CdMe2 affords the novel Zn/Cd mixed compound [Pd(CdMe)(4)(ZnCp*)(4)] (2). The related Zn/Cd mixed compound [Mo(ZnCp*)(3)(CdMe)(9)] (3) is prepared by reaction of [Mo(ZnCp*)(4)(GaMe)(4)] with an excess amount of CdMe2. All compounds were analyzed by H-1 and C-13 NMR spectroscopy, elemental analysis, and single-crystal X-ray diffraction. The bonding situation of these highly coordinated, metal-rich molecules 1-3 were studied by quantum-chemical calculations using density functional theory (DFT) at the BP86/TZ2P+ level, atoms-in-molecules (AIM) analysis, and energy-decomposition analysis (EDA), as well as the its natural orbitals for chemical valence variation (EDA-NOCV) and including the hypothetically all-Hg-coordinated ana-logues. The results point out that the radial interactions M-M' in the icosahedral compounds that have twelve ligands are best described as classical electron-pair-sharing covalent bonds, whereas the dodecahedral species, which have eight ligands, exhibit metal-ligand donor-acceptor bonds. The attractive interactions between the metal-ligand fragments M'R by means of M'-M' bonds are weaker but not insignificant. All complexes fulfill the 18electron rule. The analysis clarifies the electronic structures as being distinctly different from typical endohedral clusters M@(M '' R)(n) that exhibit strong peripheral M''-M'' interactions: The M'-M' bonds are not strong enough to yield stable (M'R) n cages.

• 出版日期2010