Spectra solid-state electronic

Experimentally it is best to use a spectrometer whose electronics have solid state capabilities since it is necessary to have short 90° pulse lengths (typically 5-15 /is, which demands up to 1 kW rf power) and as short as possible a receiver dead-time. Even so, rolling base lines will interfere seriously with lines that are more than 1 kHz wide when single 90° pulses are used, but special pulse sequences are now available" which can substantially eliminate many of these problems. Effects due to spin coupling are normally eliminated by quadrupolar relaxation, but in SF V( S- F) is 251.8 Hz, and this symmetrical species yields" a beautiful binomial septet for its spectrum, the central line having a Tx of 10 s. In the sulfone I /( S-H) is ca. 6 Hz and in the absence of proton decoupling the spectrum is a poorly resolved triplet. As a general rule in NMR Ti = Ti and can be obtained... 

The intriguing radical cation [Te N(SiMe3)2 2] " is formed (as the blue AsFg salt) by oxidation of Te[N(SiMc3)2]2 with AsFs. This deep blue salt is monomeric in the solid state with d(Te-N) = 1.97 A, consistent with multiple bonding. The broad singlet in the EPR spectrum indicates that the unpaired electron is located primarily on the tellurium... 

According to its IR spectrum, phospharinane 141 exists in the solid state exclusively as the tautomer 141b possessing the localized electronic structure (Scheme 43) (83UK1761). However, by means of NMR and IR spectroscopy, it was shown that in CDCI3 solution the delocalized structure 141a is also present, although at a low relative concentration. 

Chemically the iron complex 18 is reduced by K/Na alloy in THF to give a green solution of the salt 57. The d7 anion in 57 has been characterized by its ESR spectrum in frozen solution (62). Similarly, on treatment with sodium amalgam, the cobalt complexes 7 and 13 yield dark brownish-red solutions of 58 and 59, respectively. A surprisingly robust PPh4+ salt 60 (mp 158-159°C) could be isolated. Solution and solid state magnetic measurements confirm the presence of two unpaired electrons in these 20-e species as in NiCp2 (60). 

Potassium hexafluororhodate(III), K3RI1F6, was obtained by Peacock (22) as a buff solid by fusion of K3Rh(N02)6 with KHF2. It was found to be diamagnetic (19), thus implying the presence of a low-spin lA g (tig) ground state. The electronic spectrum was studied by diffuse reflectance by Schmidtke (23) over the range 15—45 kK., as shown in Fig. 3, and the bands observed are listed in Table 3. 

The electrides. Following many experimental difficulties, Dye and coworkers were able to demonstrate that reaction of 18-crown-6 with caesium in a 1 2 ratio (under specified conditions) leads to isolation of shiny, black crystals of a product of composition Cs+(18-crown-6)2 (El-laboudy, Dye Smith, 1983 Dye Ellaboudy, 1984). The solid-state 133Cs nmr spectrum, the esr spectrum, and the magnetic susceptibility of this product all indicated that it was of type Cs+(l8-crown-6).e" that is, a crystalline electride in which the anion is a single electron. In overall terms, this exotic class of compound may be considered to lie on the border between metals and non-metals. 

While the first electrochemical reduction potential provides an estimate for Ac (assuming it is a reversible process), the second and higher reduction potentials do not provide the spectrum of single electron affinity levels. Rather, they provide information about two-electron, three-electron, and higher electron reduction processes, and, therefore, depend on electron pairing energy. Thus, the utility of solution-phase reduction potentials for estimating solid-state affinity levels is... 

The alternative approach to detection and analysis incorporates a solid state detector and a multichannel pulse height analysis system. The crystals used are of silicon (of the highly pure intrinsic type), or the lithium drift principle (p. 463 etseq.) is utilized. All emitted radiations are presented to the detector simultaneously and a spectrum is generated from an electronic analysis of the mixture of voltage pulses produced. Chapter 10 contains a more detailed account of pulse height analysis and solid state detectors. Production of an X-ray spectrum in this way is sometimes known as energy dispersive analysis ofX-rays (EDAX) and where an electron microscope is employed as SEM-EDAX. 

The broad PL emission spectra of some metal chelates match the requirements for white emission. Hamada et al. investigated a series of Zn complexes and found bis(2-(2-hydroxy-phenyl)benzothiazolate)zinc (Zb(BTZ)2, 246) is the best white emission candidate. An OLED with a structure of ITO/TPD/Zn(BTZ)2/OXD-7/Mg In showed greenish-white emission with CIE (0.246, 0.363) with a broad emission spectrum (FWHM 157 nm) consisting of two emission peaks centered at 486 and 524 nm (Figure 3.14) [277], A maximum luminance of 10,190 cd/m2 at 8 V was achieved. The electronic and molecular structure of Zn(BTZ)2 have been elucidated by Liu et al. [278]. There is evidence that the dimeric structure [Zn(BTZ)2]2 in the solid state is more stable than its monomer Zn(BTZ)2. They also found that the electron transport property of Zn(BTZ)2 is better than that of Alq3. 

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