Plane table

The presence of first-order reflections from all types of pyramidal planes (Table II) eliminates from consideration all space-groups based on any but the simple orthorhombic lattice r0. Of these the following are further definitely eliminated ) by the occurrence of first-order reflections from the prism planes given in Table III ... 

Interestingly, after reaching the maximum at the 6-membered cycle, the yields drop again. This decrease in efficiency occurs despite the appreciable reduction in the distance between the terminal acetylenic carbons relative to the 6-membered analogue. Here, the efficiency may simply be a function of how photochemical excitation is distributed in the reactive excited state. Calculated enediyne geometries suggest the cyclization is more efficient for those enediynes where the terminal phenyl groups are rotated outside of the enediyne plane (Table 3). 

As the temperature was raised from 180 to 228 K (Figs. 12A, B, D, and E), a new spectrum with absorptions at 2870, 2795, 1340, and 1125 cm 1 gradually grew into dominance which, as Lapinski and Ekerdt were the first show on Ni, corresponds to the ethylidyne species. At yet higher temperatures (Fig. 12B), a fifth spectrum grew at the expense of that from ethylidyne, the possible nature of which will be explored in the next section. It is very remarkable that none of the four low-temperature spectra found, with their related species, on the oxide-supported Ni catalysts has been identified on single-crystal Ni planes (Table VI). 

In the dihydrothiazolo-azinium or -azinone systems the six-membered ring is planar, whereas the five-membered ring has the envelope conformation. Thus in anhydro-2a,3/3-dicarboxy-2,3-dihydro-5-methylthiazolo[3,2-a]pyridinium hydroxide, S-l and C-3 are coplanar (within 0.05 A) with the pyridine ring, whereas C-2 is 0.60 A out of the plane (Table 14) (71ACS118). 

The X-ray data for 2-ethoxycarbonylimino-2//-[l,2,4]thiadiazolo[2,3-a]pyridine monohydrate show the molecule to be planar except for the ethoxy group which is bent out of plane (Table 27). 

According to the Woodward-Hoffmann rales, five concerted transition states are possible for the Claisen as well as the closely related Cope rearrangements chair, boat, twist, cross and plane (Table 6). Only the chair and boat TS have to be considered, as twist, cross and plane are antarafacial-anta-rafacial processes and require highly elevated temperatures. - For the correct prediction of product stereochemistry it is nevertheless crucial to know the preference for chair- or boat-like transition state in the actual 3,3-sigmatropic shift. 

It should be noted that complexing ions are characterized with definite steric structures. The most widespread drug complexes with coordination number 6 are built according to the type of the octahedron, with the coordinated groups oriented to the octahedron s peaks (Table 1). The drug complexes with coordination number 4 also can be built on the type of tetrahedron or on the type of plane (Table 1). 

Metal ENDOR. ENDOR spectra from the central ions Cu, Ag and Ag have been recorded for Bq in the porphyrin plane (Table 6.1). In both compounds the metal hfs tensors are axially symmetric within experimental error. The ratio of the Ai values of the two Ag isotopes, Ai( Ag)/Ai( Ag) = 0.8664 0.0002, is significantly smaller than the ratio of the two nuclear g-factors gn( Ag)/gn( ° Ag) = 0.8698. This difference arises from the penetration of unpaired s-electron density into the nuclei ° Ag and Ag which have different nuclear charge distributions (hyperfine anomaly )). 

Sb crystallizes in the same rhombohedral system as Bi. Sb(lll) exhibits an appreciably more negative value of =0 compared with the other planes (Table 4). The... 

Relative to these deviations, we have also calculated other parameters regarding the Si atoms with the Bader partition scheme of the electron density for both (110) and (100) planes (Table 11.3). The obtained Bader charges for the Si(sp ) or Si(sp ) atoms possess opposite signs for both (110) and (100) planes. The different charges are coherent with the proposed origin of the band gap of 0.5 eV for a partially ionic Si-Si bond [45], which explains the non-metallic character of the Si (100) surface [51]. Small differences are observed between the Si(ip ) Bader charges for the (110) and (100) surface but the Si sp ) charges coincide for both planes. 

Inclusion of two fused benzo groups causes dibenzo-18S6 to differ conforma-tionally from the unsubstituted parent compound [69]. All six donor atoms -indeed, the entire ligand except for the benzo groups - lies essentially in a plane (Table 1). The benzo groups lie centrosymmetrically disposed on opposite sides of the Sg plane at an angle of 83° (cf dibenzo-1806, 124°). The two non-benzo S atoms adopt anti placements about their bonds to the adjacent carbon atoms they also assume an exodentate orientation with respect to the crown cavity. 

Structurally [Ru(benzo-9S3)(CO)Br2] consists of a facially coordinated benzo-9S3 with the benzo group approximately perpendicular to the S3 plane (Table 1). In its conformation the 9S3 ring closely resembles analogous complexes of the unsubstituted ligand. Owing to the trans influence of CO the unique Ru-S, s distance exceeds the other two by over 0.1 A (Table 1). 

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