Explaining the nature of the E-O chemical bond (E = Si, Ge, Sn) has been a great challenge for theoretical chemists during the last decades. Among the large number of models used for this purpose, the one based on hyperconjugative interactions sheds more light on the nature of chemical bonding in siloxanes. Starting from this concept, this study aimed to evaluate the impact of siloxane type hyperconjugative effects on the structural features of germoxanic and stannoxanic species and in addition to assess if p-d-like back-bonding interactions can also play important roles in determining the particular structures of these heavier analogues of ethers. Natural bond orbital deletion (NBO DEL) optimizations, carried out at the DFT level of theory, revealed that hyperconjugative effects dictate to a large extent the structural behavior of these species. Furthermore, this study points out that p-d back-bonding interactions also influence the equilibrium geometry of these species, although acting as a secondary electronic effect within the E-O-E moieties (E = Si, Ge, Sn).

The synthesis and characterization of an E2 CE2 bis-sulfonyl aryl pincer ligand and its efficiency for the stabilization of compounds containing low-valent Group 14 elements (Ge and Sn) are reported. Complexation reaction of these metallylenes with iron or tungsten complexes resulted in the modulation of the oxygen atoms of the sulfonyl groups implicated in the stabilization of the Group 14 elements, demonstrating the original adjustable character of the bis-sulfonyl O2 S-C-SO2 aryl pincer.

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We propose that the global minimum structure of the Au 10 2+

New substituted 2,3‐dichloro‐1‐λ3σ2‐P,3‐λ3σ3‐P‐diphosphapropenes Mes*P=C(Cl)‐P(Cl)tBu (1) (Mes* = 2,4,6‐tri‐tert‐butylphenyl) and the oxidation compounds Mes*P=C(Cl)–P(=E)(Cl)R [R = tBu, E = S (2), O (3); R = Mes, E = O (4)] are reported. From the reaction of 2 with W(CO)5(thf) the chelate compound W(CO)4[Mes*P=C(Cl)–P(S)(Cl)tBu] (5) was obtained. Reaction of 1 or 2 with PdCl2(cod) led to PdCl2[cyMes*PC(H)(Cl)–P(Cl)tBu] (cyMes*P = 5,7‐di‐tert‐butyl‐3,3‐dimethyl‐1‐phosphaindane) (6) or PdCl2[cyMes*PC(H)(Cl)–P(S)(Cl)tBu] (7), in which the coordination to the Pd atoms is accompanied by intramolecular addition of CH(tBu) of Mes* to the P=C bond of the dichlorodiphosphapropene. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)