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Eiichi Tabei Shigeru Mori Fumio Okada Susumu Tajima Kazuo Ogino Yuzuru Okawara Seiji Tobita 《Journal of mass spectrometry : JMS》1992,27(6):702-708
The fragmentations of tetramethoxysilane ((CH3O)4Si (1)) and trimethoxymethylsilane ((CH3O)3SiCH3 (3)) induced by electron impact were investigated by mass-analysed ion kinetic energy (MIKE) spectrometry and a deuterium-labelling study. These molecular ions begin to fragment by the loss of CH3 or CH3O. These fragmentations are followed by the loss of an aldehyde molecule (H2CO), as commonly observed in the mass spectra of alkoxysilanes. Almost complete scrambling of the methoxy hydrogens takes place in the metastable molecular ion, [1]+˙, prior to the decomposition. On the other hand, a moderate extent of scrambling of the hydrogens takes place in [3]+˙. The fragmentations of [1]+˙ and [3]+˙ were compared with those of the corresponding carbon analogues, tetramethoxymethane ((CH3O)4C (2)) and 1,1,1-trimethoxyethane ((CH3O)3CCH3 (4)), respectively. 相似文献
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Alkynylnickel complexes trans-C6Cl5Ni(PPhMe2)2CCR (IIIa, R H; IIIb, R Me; IIIc, R Et; IIId, R CH2OH; IIIe, R CH2CH2OH; IIIf, R Ph; IIIg, R C6H4OMe-p) have been prepared from trans-[C6Cl5Ni-(PPhMe2)2L]ClO4 and monosubstituted acetylenes in the presence of triethylamine, and their reactions with alcohols in the presence of perchloric acid were studied. Complexes IIIa and IIIe afforded alkoxycarbene complexes trans-[C6Cl5Ni-(PPhMe2)2{C(OR′)Me}]ClO4 (IVa, R′ Me; IVb, R′ Et; IVc, R′ n-Pr) or trans-C6Cl5Ni(PPhMe2)2{}]ClO4(IVd), respectively, but IIIb either decomposed or afforded trans-C6Cl5Ni(PPhMe2)2CHC(OMe)Me, depending on the amount of acid used. Treatment of IVaIVd with amines resulted in deprotonation to give α-alkoxyvinyl complexes, trans-C6Cl5Ni(PPhMe2)2C(OR′)CH2 (VIaVIc) or trans-C6Cl5Ni(PPhMe2)2 (VId), the reaction being reversible. A 1H NMR study indicated: (i) that the carbene methyl and the vinyl protons IV or VI are D-exchangeable by MeOD without catalyst; (ii) that the basicity of VIa is comparable to those of amines; (iii) that the carbene complexes IVaIVc have two isomers due to hindered rotation about the C(carbene)O bond in solution, IVb existing in the Z-form in the solid state; (iv) that the rotationalbarriers (°G≠) about the C(carbene)O bond in IVb and the NiC-(carbene) bond in IVd are 20 (or more) and 11.7 kcal/mol, respectively. These results are explained in term of double bond character of the carbene carbon and its surrounding atoms. 相似文献
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A series of multiply meso-substituted porphycenes has been prepared by acetoxylation of 2,7,12,17-tetra-n-propylporphycene (H2TPrPc), and the molecular structure of 9,10-diacetoxy-2,7,12,17-tetra-n-propylporphycene (2a) determined by single-crystal X-ray diffraction analysis. The 1H NMR and optical properties have also been investigated. 相似文献
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Allylic tri-n-butyltins can be prepared easily by the treatment of allylic sulfones or sulfides with tri-n-butyltin formate in refluxing xylene. 相似文献
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Takeshi Endo Makoto Okawara 《Journal of polymer science. Part A, Polymer chemistry》1980,18(7):2121-2128
Alloxan or ninhydrin radical anions which are obtained from alloxantin or hydrindantin, respectively, by treatment with triethylamine could be trapped in stable condition by polymer cations that contains 1-benzyl-3-carbamoyl pyridinium or 1-benzylpyridinium salts structure. 相似文献
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