Compounds Containing Group 16 Atoms

The novel monoanionic tripodal ligands [MeB(Im )2(Pz ) ], methylbis(l-methylimidazol-2-yl)(pyrazol-l-yl)borate have been synthesised and their mode of coordination to a nickel atom investigated. It is found that such coordination depends on the steric congestion around the boron atom. Deprotonation from an N-methyl group in 2-[l-(dimethylamino)-l-methylethyl]phenylborane derivatives has been observed.The specific reaction to be followed is that of 2-[l-(dimethylamino)-l-methylethyl]phenyllithium (Ar Li) with a trialkyl borate B(0R)3 in a 3 1 ratio. The product is l-Ar -3,4,4-trimethyl-l,2,3,4- 

Three new complexes BPh2(mqp) (3), Al(Me)(mqp)2 (4) and Al(mqp)3 (where mqp = 2-(4 -methylquinolinyl)-2-phenolato) have been synthesised and characterised. In 3 and 4 the mqp ligand acts only as a chelate ligand while in the last it acts both as a chelate and as a terminal ligand. The boron centre in 3 has tetrahedral geometry while the aluminium centres in the other complexes are trigonal bipyramidal. The emission spectra of these complexes in CH2CI2 solution and in the solid state have been measured and the compound Al(mqp)3 has been incorporated into an electroluminescent device. 

There are two recent reports of pentafluorophenylboron azides. The first discusses a trimeric species formed when the dichloroborane C6F5BCI2 reacts with two equivalents of trimethylsilyl azide to form C6F5B(N3)2 which trimerises 

Compound 6 is an example of an enantiometrically pure tetracoordinate boron compound. In contrast to the exhaustive investigations of substitution reactions at chiral carbon atoms much less attention has been paid to isoelec-tronic and isostructural boron atoms. In the current work, in the first such investigation of its kind, 6 has been used to investigate the stereochemistry of a number of substitution reactions occurring at a boron atom. The presence of a bromine atom attached to the boron atom gives a ready site for substitution reactions while the presence of a phosphine ligand helps to confer air- and moisture-stability on the product. 

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Design acyclic compounds containing groups of C, H and O atoms (select all molecule types with C, H 0 atoms)... 

Of course, any tetrahedral atom, not just caibon, that has four different groups bonded to it is a chirality center, and compounds containing such atoms will exist as a pair of enantiomers. Many such compounds have been prepared and resolved, including the following quaternary ammonium salt and the silicon compound ... 

Many organic compounds contain oxygen atoms bonded to alkyl groups. The major classes of oxygen-containing compounds are alcohols, ethers, ketones, aldehydes, carboxylic acids, and acid derivatives. We will cover their nomenclature in greater detail in upcoming chapters. 

Dichlorofluoromethyl)trimethylsilane and trimethyl(trifluoromethyl)silane react (under the conditions of nucleophilic catalysis by fluoride ions) with compounds containing halogen atoms at C = N or N = groups, e.g. formation of 6 and 7. Such halogen atoms can be easily substituted by dichlorofluoromcthyl or trifluoromethyl groups. 

As the quantification limit is equal to 10 times the standard deviation measured in the case of the blank test, it is approximately 0.1% at best for compounds containing groups of atoms with a high absorption capacity. 

Official methods of chemical analysis of conventional diesel are often not adequate to characterize biodiesel. Tests for the levels of sulfur and aromatic components in biodiesel are useful but usually reveal that the concentrations of compounds containing these atoms or functional groups are very low. Analysis of biodiesel chemistry can reveal characteristics conferred by the source of the oU, the method of manufacture, and duration of storage (20, 21). For example, free and bound glycerol is measured to ascertain if biodiesel has been completely formed during synthesis. Fatty acid content, residual soaps, iodine value, peroxide value, and fatty acid composition all may reflect the quality of biodiesel (Table 1) but are unimportant and inapplicable in conventional diesel fuel quality determination. 

These compounds in fertilizer are made of cations and anions in a ratio so there is no overall charge, like all other ionic compounds. But instead of ions made of a single atom, these compounds contain groups of atoms that are ions. 

It is perhaps unnecessary to stress that a formula should correspond as closely as possible to the structure of the compound, that is, to the molecule or other grouping present, as, for example, NasBsOg for sodium metaborate, which contains cyclic B3O6 ions. Compounds containing metal atoms in two oxidation states are of interest in this connection. If the oxidation numbers differ by unity the formula does not reduce to a simpler form (for example, Fe304, Cr2ps), but if... 

In C-alkylation of other compounds containing nitrogen atoms. Chi s group [35] has done a lot of work. They have described a novel approach for pyrrole C-alkylation in which [BMIM][SbFg] and CH CN as a mixture was onployed for the synthesis of 2-(3-phenylpropyl)pyrrole from pyrrole and 7-bromo-3-phenylpropane with the results that 81% yield was achieved at 115 C for 44 h with 5% yield of dialkylated compound. It is obvious that the ionic Uqnid demonstrated an important driving force in the regioselective alkylation of pyrrole. Moreover, it is worthy to be noted that in this reaction, no Lewis add/base catalysts were needed. 

Competition of a different kind occurs in reactions of esters and lactones since these compounds contain hydrogen atoms alpha to a carbonyl group and alpha to an ether function. A priori, abstraction of either type of hydrogen might be expected. In fact, reaction of phenanthrenequinone at 4358 A led in quantitative yield to products of reaction at the carbon atom alpha to the ether function (52,53) in ethyl acetate 132>, ethyl propionate 132>, and y-butyrolactonee) 110>. 

Radicals.- Many compounds contain groups of atoms which pass from one compound to another, and, in many reactions, behave like elementary atoms. Such groups are called radicals, or compound radicals. 

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