Structural and spectroscopic

The importance of the solid-liquid interface in a host of applications has led to extensive study over the past 50 years. Certainly, the study of the solid-liquid interface is no easier than that of the solid-gas interface, and all the complexities noted in Section VIM are present. The surface structural and spectroscopic techniques presented in Chapter VIII are not generally applicable to liquids (note, however. Ref. 1). There is, perforce, some retreat to phenomenology, empirical rules, and semiempirical models. The central importance of the Young equation is evident even in its modification to treat surface heterogeneity or roughness. ... 

JCAMP. jdx,. dx,. cs Joint Committee on Atomic and Molecular Physical Data structure and spectroscopic format nmm.jcamp. org/ 56... 

Inadequate availability of experimental data can considerably inhibit the development of improved energy functions for more accurate simulations of energetic, structural, and spectroscopic properties. This has led to the development of class II force fields such as CFF and the Merck Molecular Force Field (MMFF), which are both based primarily on quantum mechanical calculations of the energy surface. The purpose of MMFF, which has been developed by Thomas Halgren at Merck and Co., is to be able to handle all functional groups of interest in pharmaceutical design. 

The physical data index summarizes the quantitative data given for specific compounds in the text, tables and figures in Volumes 1-7. It does not give any actual data but includes references both to the appropriate text page and to the original literature. The structural and spectroscopic methods covered include UV, IR, Raman, microwave, MS, PES, NMR, ORD, CD, X-ray, neutron and electron diffraction, together with such quantities as dipole moment, pX a, rate constant and activation energy, and equilibrium constant. 

The temperature-dependent NMR spectrum of the ion can be analyzed to show that there is a barrier (8.4 kcal/mol) for the ring flip that interchanges the two hydrogens of the methylene group. The C-NMR chemical shift is also compatible with the homoaromatic structure. MO calculations are successful in reproducing the structural and spectroscopic characteristics of the cation and are consistent with a homoaromatic structure. ... 

Early work established that S4N4 forms di-adducts with alkenes such as norbornene or norbomadiene. Subsequently, structural and spectroscopic studies established that cycloaddition occurs in a 1,3-S,S"-fashion. The regiochemistry of addition can be rationalized in frontier orbital terms the interaction of the alkene HOMO with the low-lying LUMO of S4N4 exerts kinetic control. Consistently, only electron-rich alkenes add to S4N4. 

The series AuX (tmpp) shows clear patterns [81] in structure and spectroscopic parameters (Table 4.9) (X = Cl, Br, I). 

Values of and Qb can be calculated for molecules in the gas phase, given structural and spectroscopic data. The transition state differs from ordinary molecules, however, in one regard. Its motion along the reaction coordinate transforms it into product. This event is irreversible, and as such occurs without restoring force. Therefore, one of the components of Q can be thought of as a vibrational partition function with an extremely low-frequency vibration. The expression for a vibrational partition function in the limit of very low frequency is... 

Revised Values of Double-Bond Covalent Radii.—This investigation has led to the value 1.34 A. for the carbon-carbon double-bond distance, 0.04 A. less than the value provided by the table of covalent radii.111 4 Five years ago, when this table was extended to multiple bonds, there were few reliable experimental data on which the selected values for double-bond and triple-bond radii could be based. The single-bond radii were obtained -from the study of a large number of interatomic distances found experimentally by crystal-structure and spectroscopic methods. The spectroscopic value of the triple-bond radius of nitrogen (in N2) was found to bear the ratio 0.79 to the single-bond radius, and this ratio was as-... 

The first example of a neutral aluminum complex of diazaphosphane, the 1,3,2,4-diazaphosphaluminetidine 50, Eq. (4), has been synthesized by the dehydrogenation reaction between Lewis acid-base adduct H3AI <— NMca and fBuP[N(H)fBu 2 49. The product fBuP(NfBu)2(H)Al [Pg.111]

Extensive quantum chemical calculations have been reported for sulfur-rich compounds in the past two decades. These calculations were used to investigate molecular structures and spectroscopic properties, as well as to understand the nature chemical bonding and reaction mechanism. Many high-level ab initio calculations were used for interpretation of experimental data and for providing accurate predictions of molecular structures and thermochemical data where no reliable experimental values are available. In recent years, density functional calculations have been extensively tested and used on many first- and second-row compounds. These proven DFT methods look promising for larger systems because for their computational efficiency. 

Table 4. Chemical structure and spectroscopical and photophysical properties of riboflavin (RF) in aqueous phosphate buffer pH 7.4 (Valle et al, 2011).

We will use here the main results obtained for two complex and distinct situations the structural and spectroscopic information gathered for D. gigas [NiFe] hydrogenase and AOR, in order to discuss relevant aspects related to magnetic interaction between the redox centers, intramolecular electron transfer, and, finally, interaction with other redox partners in direct relation with intermolecular electron transfer and processing of substrates to products. 

Duffy NW, Lane DW, Ozsan ME, Peter LM, Rogers KD, Wang RL (2000) Structural and spectroscopic studies of CdS/CdTe heterojunction cells fabricated by electrodeposition. Thin Sohd Films 361 314-320... 

Barnard, P.J., Baker, M.V., Bemers-Price, S.J., Skelton, B.W. and White, A.H. (2004) Dinudear gold(I) complexes of bridging bidentate carbene ligands Synthesis, structure and spectroscopic characterisation. Dolton Transactions, 1038-1047. 

Chan, M.C.-W. and Che, C.-M. (1998) Application of 2,6-diphenylpyridine as a tridentate [C N C] dianionic ligand in organogold(III) chemistry. Structural and spectroscopic properties of mono- and binuclear transmetalated gold(III) complexes. Organometallics, 17, 3505-3511. 

Recently we investigated ferromagnetic properties of CoPt bimetallic nanoparticles [232,233]. CoPt3 nanoparticles can be prepared by a two-step reduction using NaBH4 as a reductant. The bimetallic nanoparticles were characterized by thermogravimetry (TG) and differential thermal analysis (DTA), FT-IR, TEM) and XRD. Structural and spectroscopic studies showed that the bimetallic nanoparticles adopt an fee crystalline structure with an average particle size of 2.6 nm. SQUID studies revealed... 

Iron centers that are more electron-deficient than iron(III) compounds are used for efficient and highly specific oxidation reactions in, for example, heme and nonheme enzymes [166-172]. Most iron(IV)-complexes found in biological reaction cycles possess terminal or bridging 0x0 groups as is known from a large number of structural and spectroscopic investigations. With the exception of iron(IV)-nitrido groups, nonoxo iron(IV) centers very rarely take part in such reactions. 

The nature of reagents prepared under different conditions has been explored both structurally and spectroscopically.177 C2H5ZnCH2I, Zn(CH2I)2, and ICH2ZnI are all active methylene transfer reagents. 

B. Hydroxide Derivatives of Zinc and Cadmium 1. Syntheses, Structures, and Spectroscopic Properties... 

Stabilization of quinone methides by coordination to transition metals might have various applications, beyond the important structural and spectroscopic studies of these coordinated compounds. For example, it is possible to manipulate their structure while coordinated to the metal center and affect their controlled release and trapping, leading to new synthetic procedures. 

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