Nonclassical interactions

The complex OsHCl(CO)(P Pr3)2 reacts with HX (X = H, SiEt3, Cl) molecules to give derivatives of the type OsXCl(r)2-H2)(CO)(P Pr3)2 (X = H, SiEt3, Cl), where the hydrogen atoms bonded to the osmium atom undergo nonclassical interaction (Scheme 16). 

The term secondary interactions was introduced in chemistry by Alcock to describe all types of interactions not explainable by conventional theories, i.e. for nonclassical interactions.As has been recently discussed, the term secondary... 

An alternative example of the metal-in-a-box model is provided by the monocationic [(Ph4B)Ba(thf)4][BPh4], shown in Figure 34. Here, the metal coordination sphere is completed by jr-arene interactions to a BPI14 anion, which binds in a sandwich-type interaction to the metal. Secondary, nonclassical interactions between the monocation and the noncoordinated anion provide additional stabilization. Interestingly, analogous reaction conditions for the smaller metals calcium and strontium afford the dicationic species [M(thf) ][BPli4]2 (M = Ca, n = 6 M = Sr, n = 7), that are... 

Under a hydrogen atmosphere, complex 191 affords 190, which shows a nonclassical interaction between two of the four hydrogen atoms bonded to the osmium atom. In solution, these atoms exchange their positions giving in the H NMR spectra only one resonance, which has T, of 32 ms at -67 KT [77]. 

Keywords nonclassical interactions, agostic bond, hypervalent bond, silicon, hydride... 

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