Fenske-Hall calculation

The four-coordinate complexes [Mo(SBu,)4] and [Mo(NR2)4] are also diamagnetic. The UV-PE spectrum of [Mo(SBu )4] exhibits a low ionization potential at 6.8 eV which has been assigned to the ionization of electrons with predominant molybdenum Adz2 character, on the basis of discrete variational-Xa MO calculations on the model compounds [Mo(SH)4] and [Mo(SMe)4].210 For [Mo(NR2)4] (R = Me, Et), the UV-PE spectrum contains a low energy ionization at 5.3 eV which has been attributed to ionization from the molybdenum Adx2-y orbital. This assignment was based on Fenske-Hall calculations on [Mo(NMe2)4].2U... 

We thank the National Science Foundation, the donors of the Petroleum Research Fund administered by the American Chemical Society, and the Wrubel Computing Center for financial support. We are also indebted to Drs. John Huffman, Kirsten Folting, and William Streib at the Molecular Structure Center for single-crystal X-ray studies, to Mr. David L. Clark for assistance with the Fenske-Hall calculations, and to Drs. Dennis Lichtenberger and Edward Kober for obtaining photoelectron spectra. 

Fio. 23. Eigenvalue spectra for (A) Co3(CO)9CMe and (B) H3Fe3(CO)qCMe from Fenske-Hall calculations (159). 

Figure 50. Molecular orbital energy diagrams resulting from a Fenske-Hall calculation on Movi(S2C2H2)3 [adapted from (410)] and DFT calculations [unpublished work of the authors] on Movi(S2C2H2)3 and MoIY(S2C2H2)3. Occupied MOs are in bold.

Figure 57. Fenske-Hall calculated correlation diagram relating the sulfur-fold and MO energy of Movi(S2C2H2)3. [Adapted from (410).]...

Table 1.1. Eigenvalues and eigenvectors for B2 from a Fenske-Hall calculation...

FIGURE 1. Molecular orbital diagram for (CO)3Co( -C3H3) based on Fenske-Hall calculations ... 

For alkynes bonded to higher nuclearity clusters no overall molecular orbital treatment encompassing all the variations in geometry has appeared yet. However, there are a small number of examples of specific alkyne-substituted clusters which have been analyzed by one type of molecular orbital treatment or another, and a number of these have been mentioned in Section III,G because photoelectron spectroscopy has been used as an aid to assignments. CNDO calculations (397) on Fe3(CO)9(EtCCEt) (390) and M3(CO)9(/i-H)(CCR) (M = Ru, Os) (391) and Fenske-Hall calculations (398) on Co4(CO)10(PhCCH) (389) indicate that there is net back donation into alkyne n orbitals, which increases as the number of metal atoms to which the ligand is bonded increases. The normally accepted view of considering the interaction... 

Then, it is assumed that each AO is an eigenfunction (e) of the kinetic energy and potential term for that center [17] and the Mulliken and point charge approximation are applied to the three-center potential terms. In the Fenske-Hall calculation, the two-center kinetic energy is calculated for the given basis set and subtracted as shown in Eq. (8)... 

The electronic structure of Cp2Ni2( x-S)2(MnCO)3 (S = 1/2 ground state) has been described by Fenske-Hall calculations [19]. Here, we will describe those results first and then compare them with DFT and HFR calculations. The MO diagram shown in Scheme... 

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