Group 14 compounds theoretical studies

M. Sugimoto, M. Anzai, K. Sakanoue, and S. Sakaki, Modulating fluorescence of 8-quinolino-lato compounds by functional groups a theoretical study, Appl. Phys. Lett., 79 2348-2350 (2001). 

XRD measurements showed that the compound has a cubic lattice with the lattice parameter a = 0.6443 nm and metal atom arrangement of the fluorite type (space group Fm3m). Theoretical studies of its X-ray absorption spectra were conducted soon after its discovery by Orgaz and Gupta [35]. 

Because the maximum of relativistic effects in the ns shell in group 11 is at element 111, there has been considerable interest in the electronic structures of its compounds. Theoretical studies (Seth et al., 1996 Liu and van Wiillen, 1999) of the simplest molecule 111H show that the bonding is considerably increased due to relativistic contraction of the 7s orbital. Theoretical studies (Seth et al., 1998a,b) of the stability of higher oxidation states support earlier predictions that the 3+ and 5+ oxidation states will be more common for element 111 than they are for Au and that the 1+ oxidation state may be difficult to prepare. 

The ultraviolet absorption spectrum of cyclohexanone reflects the n jt transition common to all carbonyls see figure IX-E-1. The data derived from gas-phase measurements of the cross sections for cyclohexanone from two different research groups [National Center for Atmospheric Research (NCAR) and Ford Scientific Laboratories (Ford)] are in reasonable agreement (Iwasaki et al., 2008). The cyclohexanone cross sections as measured in cyclohexane solution by Benson and Kistiakowski (1942) had indicated seemingly low values (cross sections shown here is significantly less than those observed for cyclopropanone, cyclobutanone, and cyclopentanone, and in fact, all other carbonyls considered in this work. It is not obvious why these significant differences exist in the probability for the n -> 7T transition for cyclohexanone and that of the other cyclic ketones and most other carbonyl compounds. Theoretical studies will be important in defining the reasons for these differences. 

Pure Elements. AH of the hehum-group elements are colorless, odorless, and tasteless gases at ambient temperature and atmospheric pressure. Chemically, they are nearly inert. A few stable chemical compounds are formed by radon, xenon, and krypton, but none has been reported for neon and belium (see Helium GROUP, compounds). The hehum-group elements are monoatomic and are considered to have perfect spherical symmetry. Because of the theoretical interest generated by this atomic simplicity, the physical properties of ah. the hehum-group elements except radon have been weU studied. 

The synthesis and characterization of the monomeric amidinato-indium(I) and thallium(I) complexes [Bu C(NAr)2]M[But(NAr(NHAr)] (M = In, Tl Ar = 2,6-Pr2CgH3) have been reported. Both compounds were isolated as pale yellow crystals in 72-74% yield. These complexes, in which the metal center is chelated by the amidinate ligand in an N, j -arene-fashion (Scheme 33), can be considered as isomers of four-membered Group 13 metal(I) carbene analogs. Theoretical studies have compared the relative energies of both isomeric forms of a model compound, In[HC(NPh)2]. ... 

The chemistry of transition metal-carbyne complexes is rather less developed than the chemistry of carbene complexes. This is almost certainly because reactions which form new carbyne complexes are relatively rare when compared with those forming metal carbenes. The few theoretical studies of carbyne complexes which are available indicate that close parallels exist between the bonding in carbene and carbyne compounds. These parallels also extend to chemical reactivity, and studies of Group 8 complexes again prove instructive. 

Apart from the diphosphaisobenzenes 300 and 307 and a briefly mentioned isopyr-idazine [140a], only compounds in which the methylene group of 162 or 221 is replaced by a heteroatom or a heteroatom group are dealt with in this section. At best, theoretical studies are known on other isoaromatic cyclic allenes [140b],... 

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