Piperidine complex

Study of the mechanism of the rhodium-catalyzed hydroamination of ethylene with secondary amines indicated that the piperidine complex trans-RhCl(C2H4)(piperidine)2 can serve as a catalyst precursor [109, 110]. 

We have previously investigated ligand release in the 6-coordinate piperidine complexes of Ni octaethylporphyrin (10). For Ni(OEP), formation of the 6-coordinate complex is not complete, and so, the picture is complicated by the presence of both 4- and 6-coordinate species in the initial sample. However, upon excitation with the pulsed laser the relative proportions of the two Ni(OEP) species change as determined by changes in the relative intensities of the 4- and 6-coordinate sets of Raman marker lines. Thus, axial ligand release is observed in the excited state generated during the... 

The infrared and Raman spectra of the [Mo6SgL6] complexes have been reported (37) (Table III). The infrared spectra have an Mo—S stretching band at 378-390 cm-1, and the Raman spectra show a distinguishing sharp peak at 411-418 cm-1 that can be attributed to the Alg totally symmetric Mo—S stretching mode. The broad band at 836 cm-1 in the piperidine complex is most likely the first overtone of the band at 411 cm-1. The ligand-deficient propylamine and pyridine cluster complexes exhibit a broadened Mo—S band at 448 cm"1 that is described as due to the loss of the octahedral symmetry by loss of ligands (37). 

The energy of the absorption maximum is 22,100 cm-1 in W(C0)5pip and 22,400 cm") in WCCO py.) Thus is larger for the piperidine complex than that for the pyridine complex and the distortions along the z axis should be greater. 

Earlier workers established the presence of a-pinene, (3-pinene, 1-a-phellandrene, dl-limonene, piperonal, dihydrocarveol, a compound melting at 161°C, P-caryophyllene and a piperidine complex from the essential oil obtained by steam distillation of ground Malabar pepper. The above compounds were identified by the classical methods of derivatization and degradation. They also reported the presence of epoxy dihydrocary-... 

The autooxidation of the bis-piperidine complex TPPFe11 (pip )2, obtained by the anaerobic autoreduction of TPPFeniCl in CDC13 with piperidine (as with other amines), yields, as expected, the bridging oxo-dimer. 

The mixed piperidine complexes are an excellent example of solubility determining an isolated reaction product. Although the literature first reported (50, 51) that PdCl2(PR3)(L) (L = piperidine) could be isolated and had a trans configuration, this study by 31P 1H clearly reveals that these complexes completely disproportionate to PdCl2(PR3)2 and PdCl2(L)2 in solution. 

The kt values are in the sequence piperidine > pyridine > 1-methyl-imidazole, which may reflect the longer axial bond lengths in the piperidine complex when compared with the imidazole species. In the oxygenation of wej< -tetrakis-(2,4,6-alkoxyphenyl)-porphinato-complexes, however, preliminary kinetic evidence is suggestive of two distinct steps in the reaction. ... 

Fig. 3.3 Molecular structures of B after irradiation in the crystals of (a) pyridine and (b) piperidine complexes...

X 3.0 X1,0 ( 9.0) mm was exposed to a xenon lamp for 28 days for the piperidine complex [10], The intensity data were collected on the BIX-1 diffractometer at the JRR-3M reactor of the Japan Atomic Energy Research Institute (JAERI). The crystal structures of the pyridine and piperidine complexes after photo-irradiation determined by nentron diffraction are essentially the same as those by X-ray diffraction. 

For the piperidine complex, almost 50 % of the 1-ce group of B was inverted to the opposite R configuration. The D9 atom is completely bonded to the chiral carbon atom, C9. No H/D exchange with the methyl hydrogen atoms was observed in the 1-ce group of B. 

The volumes of the reaction cavities for the 1-ce groups of A, B, C, and D before photo-irradiation were calculated to be 10.1, 8.4, 16.9, and 15.0 respectively. These values well explain the reason why only the 1-ce groups of C and D were partially inverted to the opposite configuration. It is impossible to divide the cavities for the 1-ce groups of C and D into two parts by the plane composed of the Co-C-C-N bonds after irradiation, because the groups take very compUcated disordered structures. Probably the ratios of the left and right parts of each cavity should be 50 50 after photo-irradiation as observed in the piperidine complex. 

Ligand substitution reactions of Group VI metal pentacarbonyl piperidine complexes, equation (14), is catalyzed by the Lewis bases THF... 

Starting from the boran-piperidine complex 368, the boron is transferred into the homoallylic double bond via a highly regioselective cyclic transition state (see 369). 

Figure 4. Thermograms of illite and nontronite-dye complexes, (a) Thermograms of illite and its complexes (1) illite (2) malachite green complex (3) methylene blue complex (4) methy violet complex (5) piperidine complex, b) Thermograns of nontronite and its complexes (1) nontronite (2) methylene blue complex (3) malachite green complex (4) methyl violet complex (5) piperidine complex.

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