Carbonyls diffraction data

Thioamides and their use in the preparation of the heterocyclic compounds are widely reported in the literature. Also they attract considerable interests in peptide chemistry. Molecular and crystal structures of some thioamide derivatives have been confirmed by X-ray diffraction data.8 10 Lawesson s reagent or phosphorus pentasulfide (P4S10) is actively used for the synthesis of thio-carbonyl compounds. Their preparation methods, reactions, applications in the synthesis of heterocycles and biological effects are mainly described in this section. 

In another failed approach, addition of 1-pyrrolidinocyclohexene 32 to ( )-( l-melhyl-2-oxoindolin-3-ylidene)acetophenone 31, followed by acid hydrolysis, could be controlled simply by changes in the reaction temperature, and was found to give diastereoselectively compounds 33 or 34. The latter compound was shown by NMR and X-ray diffraction data to have the suitable geometry to allow the creation of the crucial bond between the position adjacent to the cyclohexanone carbonyl and the oxindole C-4 position. 

The formula and bond distances of the metallic carbonyls are given below, the latter being obtained from electron diffraction data. (Compounds of the alkali and alkaline earth metals with formulae of the type K (GO)g have been shown to be phenolates of hexahydroxybenzene.)... 

A problem arose when the X-ray crystal structure of [Mn(CH3)(CO)5] was attempted (55). Results showed that the solid phase was almost entirely orientationally disordered each of the six coordination sites around the manganese atom was found to be occupied by, on average, about five-sixths of a carbonyl ligand and one-sixth of a methyl ligand. The superimposed methyl and carbonyl carbon atoms could not be resolved, which precluded determination of any significant bonding parameters. However, the X-ray diffraction data did indicate that [Mn(CH3)(CO)5] crystallizes in... 

In keeping with the typical weakening of the C—O bond on going from free CO to coordinated CO, X-ray diffraction data show a lengthening of the C—O bond. In CO, the C—O bond length is 112.8 pm, whereas typical values in metal carbonyls for terminal and p-CO are 117 and 120 pm respectively. 

The molecular structure of l,2,3,4-tetrathiepane-6,6-dicarboxylate (8) was shown from the low-temperature (110 K) x-ray diffraction data. Two intramolecular contacts (3.124 and 3.188 A) between the two carbonyl atoms and the two terminal sulfur atoms are somewhat shorter than the sum of their van der Waals radii. These interactions appear to be important for its stabilization <94ACS652>. 

Bianchi et al retrieved the experimental electron density of Mn2(CO)io fi om a multipole analysis of accurate X-ray diffraction data at 120 K. A BP connects the two Mn atoms, but no cross BP was found between one Mn and the equatorial carbonyls of the other. The distribution of indicated closed-shell interactions for the metallic Mn-Mn bond and the dative Mn-CO bonds. An extensive analysis of the electron density, its Laplacian, a kinetic energy density G, the potential energy density V and the total energy density (= G + V), all evaluated at the BCP, leads to a classification. The Laplacian around the CO ligands shows that the carbon centroids of negative charge move toward the Mn atom indicating the polarization sense of the CO molecules. 

Infrared and X-Ray Diffraction Data for Complexes with Bridging Carbonyls... 

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