Fragmentation stability

The presence of water in the crystals can be explained by humid crystalization conditions and is proven by elemental analysis. The water adduct formation shows, that k 0, 0 -carboxylato ligands are hemilabile, chelating ligands, which can be easily displaced from one coordination site by a solvent. Thus, the carboxylato complexes 37a and 37b are equivalent to 16 VE fragments stabilized by the hemilabile carboxylato complexes. 

The photochemically produced PtCPEt fragment, stabilized as the cis- and trans-PtH (PEt- )2 complexes, has proved (54,55,56) to be an efficient and long lived homogeneous catalyst for H2/D2 exchange (Equation 17), deuteration of acetone or acetontrile (Equations 18 and 19), decomposition of formic acid (Equation 20), and hydrolysis of acetonitrile (Equation 21). Because of the catalytic promise... 

The maintenance of an octahedral geometry within the RhFe3 (PPh)2(C5 Me5)(CO)8/R.hFe3(PPh)2(C5 Me5)(CO)9 interconversion, formally caused by a two-electron addition/removal, can be understood if one considers that, in these complexes, the electrons enter or leave nonbonding frontier orbitals centred on the square-planar tetrametal fragment stabilized by the interaction with the apical phosphorus atoms [89]. 

An alternative strategy for the functionalization of polyoxometalates relies on self-assembly processes. Up to now we failed to introduced a Schrock-type alkylidyne in the lacunar undodecaphosphotungstate. As the current trend in olefin metathesis reaction now favours ruthenium catalysts, such as the Grubbs s ones, we turn to ruthenium precursors and to more stable Lappert-type carbene fragments, stabilized in the a-position by nitrogen atoms. The reaction of [PWii039p- with the carbene precursor... 

Fig. 11.16. Determination of fragment stabilization energy (SE) by comparison of (exp) with (ideal). Dq includes correction for zero point energy. Reproduced from J. Mol. Struct., 485/486, 385 (1999), by permission of Elsevier.

Although the C=C bond is known to be strong, examples of its cleavage to yield two carbyne fragments stabilized by bonding to an organometallic triangular framework are known. 

Ab-initio quantum chemical calculations at the HF/3-21G level of theory were applied to consider the nature of the active sites of sodalite P-cage of the LTA type zeolite and faujasite structures. Especially, the nature of sodium, potassium and silicon atoms encapsulated within the sodalitic P-cage, and their structural and molecular parameters have been described. We have shown that up to four sodium and four potassium atoms as well as five silicon atoms could be encapsulated within the sodalite P-cage. The unique properties of these nano-size materials relate directly to the encapsulated guest atom containing fragments stabilized within the sodalite P-cage of the LTA type zeolite or faujasite structures. 

The coefficient of critical stress intensity in tensile mode is an important parameter to investigate and predict the fracture processes /fragmentation, stability, hydraulic fracturing, rockburst, tectonic faulting, earthquakes.../. 

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