Selectivity, geometric

Our DFT calculations revealed that coordination of nitric oxide to the series of intrazeolite TMI leads to the formation of the bent MNO adducts of various spin states exhibiting generally the Cs microsymmetry with mirror plane defined by the M-N-0 moiety. Optimized structures of some representative mononitrosyl complexes are depicted in Figure 2.8, and their selected geometric parameters and molecular properties are listed in Table 2.4. 

Selected geometric parameters for catena-stibine and related complexes are listed in Table IV. 

Selected geometric parameters of crystal structures for complexes with (RSb)w (R = alkyl, aryl) ligands are listed in Table Y. 

Fig. 2. Selected geometric parameters (A) of the optimized structures of the key species for oxidative coupling for the catalytically active generic [Ni0(r(2-butadiene)2PH3] species la and the [Ni°(ri2-butadiene)3] species Fb of the C8- and Ci2-product channel, respectively, via the most feasible pathway for p2-/rans/r 2-ds-butadiene coupling (of opposite enantiofaces) along la -> 2a and Fb -> 2b. Free energies (AG, AG 5 in kcalmol-1) are given relative to the favorable stereoisomer of the respective bis(r 2-/rans-butadiene) and tris(r 2-/r

Fig. 5. Selected geometric parameters (A) of the optimized rotational transition-state structures for allylic isomerization via the r(3-1s y ,ri1(C3)-octadienediyl-Ni11 TSiSo[3a] and TSiSo[3b],...

TABLE 4. Selected geometrical parameters" (A) of all-trans-hexatriene computed at several levels of calculation ... 

The optimized geometries of (4.55a)-(4.55d) are shown in Fig. 4.17 and selected geometrical parameters are summarized in Table 4.13. The molecular shapes and NBO descriptors (not presented) generally agree with the idealized Lewis-like sd/x picture for Os(CH2)2, HW(CH2)(CH), and W(CH2)3. However, theC—W—C angle (42°) in the ground state of W(CH)2 is much smaller than expected for idealized sd1 geometry, and the optimal NBO description corresponds to a metallacyclopropene,... 

Table 4.13. Selected geometrical parameters of highly multiple-bonded...

Table 5.26. Selected geometrical parameters (bond length R, valence angle 0, and dihedral angle ) and atomic charges O (for atoms involved in the 7tCc-7tcN interaction) of the benzene TCNE complex compared with isolated monomers see Fig. 5.50...

Table 2. Comparison of selected geometric parameters derived from the experimental X-ray structure of 3 and those of the various calculated models.c...

The zwitterionic A5S7-fluorosilicates 4-22 were isolated as crystalline solids. Compounds 4-8, 13, and 17-22 were structurally characterized in the solid state by single-crystal X-ray diffraction. In contrast to the achiral zwitterions 4-16, the zwitterions 17-22 are chiral, the respective crystals consisting of pairs of enantiomers [(A)- and (C)-enantiomers]. In all cases, the /-coordination polyhedron was found to be a somewhat distorted trigonal bipyramid, with fluorine atoms in the two axial sites. This is illustrated for 6 and 19 in Fig. 1. Selected geometric parameters for compounds 4-8, 13, and 17-22 are listed in Table I. As can be seen from these data, the axial Si-F distances [1.647(2)-1.743(1) A] are significantly longer than the equatorial ones [1.589(2)-1.638(1) A]. The Si-Cl distances amount... 

As demonstrated by single-crystal X-ray diffraction, the /-coordination polyhedra of 85-87 are distorted trigonal bipyramids, with each of the axial positions occupied by the oxygen atoms. This is shown for compound 86 in Fig. 11. In all cases, the crystals are formed from pairs of (A)- and (A)-enantiomers. Selected geometric parameters for 85-87 are listed in Table XIII. As can be seen from the Si-O [1.8004(10)-1.829(6) A], Si-N [1.741(7)-1.764(6) A], and Si-C distances [1.867(8)-1.915(2) A], the A/02N2C frameworks of 85-87 are built up by five normal covalent bonds and do not involve a bonding system in the sense of the 4+1 coordination usually observed for pentacoordinate silicon species with Si-N bonds. 

Figure 5 Selected geometrical parameters of the A, A, A", and A electronic states of 16 calculated at the CASSCF(10,10)/6-31G(d) level of theory.

TABLE 3.2. Selected Geometrical Parameters and Bonding Energies for the Dimeric Structure (BH3NH3)2 Shown in Figure 3.9... 

FIGURE 21. Selected geometrical parameters of the transition structures for the epoxidation of ethylene with peroxyformic acid calculated at the QCISD/6-31G, CCD/6-31G (in parentheses), B3LYP/6-31G (in square brackets) and MP2(FC)/6-31G (in curly brackets) levels... 

Table 1 Molecular symmetry, and calculated selected geometrical parameters and hfcc s for TTTA, 1...

Table 10.7 Comparative selected geometric data for crystalline cis- and trans-[Sb N(H)R)-(g-NBu )]2 (R=C6H3Pd2-2,6) ...

Figure 1 Selected geometrical parameters of some 1,2-diazepines...

Table 3 Selected geometric parameters of thiepines (1 and 12) with Cs and C2 symmetries at the MP2(full)/6-31G and B3LYP/6-31G level of theory...

Table 1 Selected geometrical data for 2-methoxy-4-trifluoromethyl-1 H-1,3-diazepine 2...

Figure 13 Molecular structures of the diphosphine-borane 8a (open form, left) and triphosphine-borane 9 (closed form, right) with selected geometric and spectroscopic data.

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