Heavy ketones structure

It should be very important to reveal the structural features of heavy ketones and to make a systematic comparison with those of a carbonyl compound such as the bond shortening and the trigonal planar geometry which result from the sp2 hybridization between the carbon and oxygen atoms. 

Therefore, the elucidation of the intrinsic structural parameters of heavy ketones has to be done with kinetically stabilized systems. Most of the heavy ketones synthesized by steric protection with the Tbt group have provided single crystals suitable for X-ray structural analysis. The results for silanethione 38, germanethione 71b, germaneselones 75, 84, germanetellones 77,85, and stannaneselone 127, are summarized in Table III. 

Various combinations of tricoordinate heavy ketones have been synthesized as stable compounds by taking advantage of extremely bulky aryl substituents.52 54,161 167 Table 3 shows their selected structural parameters and spectroscopic properties. 

The X-ray structural analyses reveal the planar structures around the heavier group 14 elements of all the heavy ketones as well as the case of the carbon analog, ketones. This is in sharp contrast to the trans-bent structure in... 

Table 5 Structural parameters of heavy ketones Tbt(R)M=Ch. d lengths of an M=Ch double bond, EZM summation of the bond angles around M atom, Aobs percent reduction in bond lengths defined as [(single-bond lengths - double-bond length)/single-bond lengths] xlOO)...

Table 4 shows the structural and spectral data of tetra- and pentacoordinate heavy ketones stabilized by the intramolecular coordination of nitrogen... 

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