Doublet compound

All members of a diffuse series consist of compound doublets, as illustrated in Figure 7.7(b), but the splitting of the >5/2 states may be too small for the close pair of... 

Figure 7.7 (a) A simple doublet and (b) a compound doublet in the spectrum of, for example, the sodium atom... 

Figure Bl.25.2 shows the XPS spectra of two organoplatinum complexes which contain different amounts of chlorine. The spectrum shows the peaks of all elements expected from the compounds, the Pt 4f and 4d doublets (the 4f doublet is iimesolved due to the low energy resolution employed for broad energy range scans). Cl 2p and Cl 2s, N Is and C Is. Flowever, the C Is caimot be taken as characteristic for the complex only. All surfaces that have not been cleaned by sputtermg or oxidation in the XPS spectrometer contain carbon. The reason is that adsorbed hydrocarbons from the atmosphere give the optimum lowering of the surface free energy and hence, all surfaces are covered by hydrocarbon fragments [9].

Section 13 9 The methyl protons of an isopropyl group appear as a doublet and the methine proton as a septet in compounds of the type (CH3)2CHX... 

Treatment of 2 butanone (1 mole) with Br2 (2 moles) in aqueous HBr gave C4HgBr20 The H NMR spectrum of the product was charactenzed by signals at 8 1 9 (doublet three protons) 4 6 (singlet two protons) and 5 2 (quartet one proton) Identify this compound... 

A — P transition, shown in Figure 7.10(b), has six components. As with doublet states the multiplet splitting decreases rapidly with L so the resulting six lines in the spectrum appear, at medium resolution, as a triplet. For this reason the fine structure is often called a compound triplet. 

Previous expositions of photochemical laws have distinguished ptominentiy between states of singlet and triplet multiplicity (1). This distinction continues to be important with respect to photophysics of smaH organic molecules, but among inorganic and organometaHic compounds, states of other multiplicities, eg, doublet and quartet states (23), play an important role. Spin conservation characterizes electronic molecular excitations and localized... 

IR spectroscopy has been particularly helpful in detecting the presence of keto tautomers of the hydroxy heterocycles discussed in Section 3.01.6. Some typical frequencies for such compounds are indicated in Figure 4. Here again the doublets observed for some of the carbonyl stretching frequencies have been ascribed to Fermi resonance. 

P-F 153 pm). However, the F nmr spectrum, as recorded down to — 100°C, shows only a single fluorine resonance peak (split into a doublet by P- F coupling) implying that on this longer time scale (milliseconds, as distinct from instantaneous for electron diffraction) all 5 F atoms are equivalent. This can be explained if the axial and equatorial F atoms interchange their positions more rapidly than this, a process termed pseudorotation by R. S. Berry (1960) indeed, PF5 was the first compound to show this effect. The proposed mechanism is illustrated in Fig. 12.13 and is discussed more fully in ref. 91 the barrier to notation has been calculated as 16 2kJmol". ( ... 

Aminopyrroles are usually formulated as such because they are quite strong bases and do not easily lose ammonia by hydrolysis. In agreement with the amino formulation, the infrared spectrum of the a-aminopyrrole 93 (R = H) contains a v NHg doublet and a band near 1660 cm" corresponding to the NH2 deformation frequency, and the infrared spectrum of the acetamino derivative is in agreement with the structure 93 (R Ac). However, a stable imino compound, probably with structure 94, has been isolated. ... 

Reduction of epoxide 21 with lithium aluminium hydride gave a crystalline branched-chain methyl heptoside derivative 24. The NMR spectra of compounds 21 and 24 were very similar. In the spectrum of compound 24 the disappearance of the two sharp doublets at r 6.80 and 7.45 (2 protons) and the appearance of a singlet at r 8.65 (3 protons) is consistent with the reductive cleavage of epoxide 21 to give a substance 24 with a methyl substituent. The multiplet at r 7.40-8.50 ( 5 protons ) was assigned to the four protons of the two methylene groups and the hydroxylic proton. 

Fig. 1-19. The sulfur Ka spectrum from a series of compounds containing sulfur at different valences. The triplet in all the polythionates results from the superposition of the al, a2 doublets of sulfur at two different valences. (Courtesy of Faessler and Goehring, N aturwissenschaften, 39, 169.)...

The thiohalides MoSX are diamagnetic (269). In Mo4S4Br4, molybdenum transfers 12 electrons to the anions, and 12 electrons remain for the cluster M04, forming a doublet for each edge of the M04 tetrahedron (269). The diamagnetism of the compounds of the type MogCligSe can be interpreted in a similar way (273) from structure considerations. These compounds have been found to be dielectric (273). 

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