B3LYP calculations structure

The syn isomer can achieve a conjugated system with angles of up to 35° between adjacent p orbitals. The anti isomer is much more twisted. An X-ray crystal structure of the syn isomer shows C—C bond lengths between 1.368 and 1.418 A for the conjugated system (Fig. 9.3). ° The spectroscopic properties of the syn isomer are consistent with considering it to be a delocalized annulene. B3LYP calculations indicate that both the syn and anti structures are stabilized by delocalization, the syn (17.6kcal/mol) more so than the anti (8.1 kcal). ... 

Fig. 5.16 Calculated structure of ferrous nitrosyl tetraphenylporphyrin Fe(TPP)(NO), resulting from geometric optimization with the B3LYP functional and 6-3IG -I- VTZ basis set [101]. Color scheme cyan = iron, green = carbon, blue = nitrogen, red = oxygen (taken from [101])...

Thus, the structure of a-lactones, as reflected in their observed TRIR spectra, is dependent both on substituents at the a-carbon and on solvent polarity, with electron-donating substituents and polar solvents favoring a zwitterionic ring-opened structure. B3LYP calculations using SCRF methods to account for solvent polarity are consistent with these experimental conclusions. 

Figure 1 Calculated structure of the cyclopropylcarbinyl carbocation over zeolite Ysurface, at B3LYP/6-31++G(d,p) MNDO.

B3LYP calculations as described in Section 2. b Structures optimized with a 6-31 G(d) basis for the main group elements. c Also alkylperoxo complexes. d Attack of Oa of the hydroperoxo (alkylperoxo) group.e Attack of OP of the hydroperoxo group. 

Fig. 2. With DFT methods (B3LYP/LANL2DZp) calculated structures for the seven-coordinate diaqua complexes (a) [M.r (pydiene)(Ji20), (h) Ma pyalane)Qii20)2f, (c) [Mn(pyane)(H20)2] " and (d) [Mn(L)(H20)2] (on the left) and the corresponding six-coordinate species after loss of one water molecule (on the right) 34).

Fig. 14. With DFT methods (B3LYP/LANL2DZp) calculated structures for the side-on and end-on form of K[Fe (Porph)(02 )(DMSO)].

The B3LYP/6-31H-G(d,p) calculated structure (from the parent 4, no experimental structure is available since it could only be detected in solution) and the measured NMR data of 4 are given in Figure 3. 

For the epoxidation of propylene with HO—ONO, both the QCISD and CISD calculations result in a Markovnikov-type transition structure, where the electrophile is slightly skewed toward the least substituted carbon, with a small difference in the bond lengths between the spiro-oxygen and the double-bond carbons (0.106 and 0.043 A, respectively Figure 8). The B3LYP calculations also lead to an unsymmetrical Markovnikov-type transition structure (b). However, the MP2/6-31G geometry optimization results in an anti-Markovnikov-type structure (c) (Figure 8). The CCSD(T)/6-31G and BD(T)/6-31G barriers for ethylene epoxidation with HO—ONO calculated with the QCISD/6-31G ... 

Figure 16.2. Calculated structures and C=C stretching vibrational frequencies of 4, 40, and 41. Normal print B3LYP/cc-pVTZ data in italics BLYP/cc-pVTZ, bold print experimental...

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