Carbonates diamagnetism

AH the peroxides are colorless and diamagnetic when pure. Traces of the superoxide in technical-grade sodium peroxide impart a yellow color. Storage containers must be sealed to prevent reaction with atmospheric carbon dioxide and water vapor. 

A dication derived from 1,3,5,7-tetramethylcyclooctatetraene is formed at —78 C in SO2CI by reaction with SbFj. Both the proton and carbon NMR spectra indicate that the ion is a symmetrical, diamagnetic species, and the chemical shifts are consistent with an... 

Values of the diamagnetic anisotropy of benzene and other aromatic hydrocarbon molecules are calculated on the basis of the assumption that the p, electrons (one per aromatic carbon atom) are free to move from carbon atom to adjacent carbon atom under the influence of the impressed fields. When combined with the assumed values for the contributions of the other electrons (-2.0X 10-6 for hydrogen, —4.5 X10 c for aromatic carbon, — 6.0XlO-6 for aliphatic carbon) these lead to principal diamagnetic susceptibilities of molecules in approximate agreement with the available experimental data. The diamagnetic anisotropy of graphite is also discussed. 

The diamagnetic ylide complexes 34 have been obtained from the reaction of electron-deficient complexes [MoH(SR)3(PMePh2)] and alkynes (HC=CTol for the scheme), via the formal insertion of the latter into the Mo-P bond. The structural data show that 34 corresponds to two different resonance-stabilized ylides forms 34a (a-vinyl form) and 34b (carbene ylide form) (Scheme 17) [73]. Concerning the group 7 recent examples of cis ylide rhenium complexes 36 cis-Me-Re-Me) have been reported from the reaction of the corresponding trans cationic alkyne derivatives 35 with PR" via a nucleophilic attack of this phosphine at the alkyne carbon. 

Diazoalkanes are u.seful is precursors to ruthenium and osmium alkylidene porphyrin complexes, and have also been investigated in iron porphyrin chemistry. In an attempt to prepare iron porphyrin carbene complexes containing an oxygen atom on the /(-carbon atom of the carbene, the reaction of the diazoketone PhC(0)C(Ni)CH3 with Fe(TpCIPP) was undertaken. A low spin, diamagnetic carbene complex formulated as Fe(TpCIPP)(=C(CH3)C(0)Ph) was identified by U V-visible and fI NMR spectroscopy and elemental analysis. Addition of CF3CO2H to this rapidly produced the protonated N-alkyl porphyrin, and Bit oxidation in the presence of sodium dithionitc gave the iron(II) N-alkyl porphyrin, both reactions evidence for Fe-to-N migration processes. ... 

Pesek, J.J. and Mason, W.R. (1979) Carbon-13 magnetic resonance spectra of diamagnetic cyano complexes. Inorganic Chemistry, 18, 924—928. 

All atoms with an odd number of electrons must be paramagnetic. There is no way to pair all of the electrons up if there is an odd number of electrons. Many atoms with an even number of electrons are diamagnetic, but some are paramagnetic. The one of lowest atomic number is carbon (Z = 6), which has two unpaired / -electrons producing the paramagnetic behavior [He] 2s22p2. 

For more examples concerning various molecular systems in staggered conformations, the reader is referred to the compilations of diamagnetic y-gauche effects in refs. 7 and 9. The disappearance of a noticeable effect when the observed carbon atom is quaternary, that is, when no polarizable C-H bond is present, was also considered to support the above explanation (110,175). 

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