Steric Effects in the Formation of Copper and Cobalt Complexes with the Epimeric Salicylidenementhylamines
IN a previous communication1, it was reported that cobaltous ions do not react readily with salicylidene-aniline bases bearing ortho substituents on the aniline ring. In the present communication are reported some further attempts to prepare similar complexes of cobalt and copper, using as the amine components of the salicylidene bases four epimeric forms of menthylamine which, with bulky isopropyl substituents and nonplanar ring forms, may be expected to exert considerable steric resistance to a tetrahedral grouping of ligands about cobalt ions. The complexes were prepared by mixing aqueous solutions of the metal acetates with an alcoholic solution of the salicylidene base2. The results of this work are indicated in Table 1, the complexes isolated being of the form bis (salicylidenementhylamine) cobalt (copper).
Structure of Cobalt Complexes with Salicylideneanilines
THE structures of cobalt inner complexes with salicylideneanilines have not been determined, whereas the planar form of copper complexes of this type has been established beyond doubt by the isolation of cis and trans isomers1 and by X-ray investigation2. A difference in reactivity has now been observed between copper and cobalt ions with various salicylideneaniline bases which suggests a tetrahedral structure for the cobalt complexes. Attempts have been made to prepare complexes of the type bis-(salicylideneaniline)cobalt with bases containing aromatic amines bearing substituents in the ortho, meta and para positions. The compounds prepared are tabulated below together with the corresponding copper complexes previously prepared3.
Identification of Dihydroxy Aromatic Compounds in a Low-Temperature Pyrolysis Coal Tar by Gas Chromatography−Mass Spectrometry (GC−MS) and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS)
Dihydroxy aromatics in coal tar undergo rapid coupling reactions with each other and with some coal-derived species during coal pyrolysis and liquefaction. However, only limited information on the structure of dihydroxy aromatics is known. In this study, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and gas chromatography−mass spectrometry (GC−MS) were used to characterize the dihydroxy aromatics in a low-temperature pyrolyzed coal tar and its distillate and residue fractions. Negative-ion electrospray ionization (ESI) FT-ICR MS spectra of coal-tar-derived samples had low molecular masses and narrow mass ranges. Negative-ion ESI is extremely selective for the dihydroxy aromatics present in coal tar. The O2 class species had the highest ion intensity among the species in the negative-ion FT-ICR mass spectrum for each sample. Dihydroxy compounds with an aromatic core structure of benzene, indan, biphenyl (and/or acenaphthene), and naphthalene were identified in the distillate fract...