Report structure

Chapter 2 sets the stage with a brief statement of the present use of reference materials by the oceanographic community. A number of case studies have been included both to illustrate the value of such materials and to indicate the potential limitations of reference materials as a cure-all for oceanic measurements. 

Chapter 3 discusses the analysis of seawater constituents and reiterates the scientific problems that necessitate a number of seawater-based reference materials. 

Chapter 4 discusses the analysis of particulate materials such as sediments and biological materials. It outlines the current state of the science in some of these areas, and suggests that a limited number of particulate reference materials could play a significant role in moving these fields forward. 

Chapter 5 provides specific suggestions for the production and distribution of reference materials for ocean science, noting some of the potential challenges and indicating possible strategies to avoid or mitigate these problems. 

Chapter 6 provides a surranary of the committee s principal recommendations that arise throughout the report and indicates those actions that the committee found to be of the utmost priority. 

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To date, there has not been a reported structure determination of a class 11 MHC-peptide-TCR complex. However, T-cell receptors that recognize class... 

Recently Suglobova et al. (3, 4, 5) reported structural data, phase diagrams, and enthalpies of reaction of several complex fluorides of uranium(V) with alkali metals. Their observations indicate that the enthalpy of stabilization represented by the equation... 

Table III reports structural statistics relative to the solution structures of iron-sulfur proteins available from the Protein Data Bank (118). The lowest percentage of residue assignment occurs for oxidized Synechococcus elongatus Fd (119). The highest percentage of proton assignment is instead obtained for oxidized E. halophila HiPIP, with a value as high as 95% (120). A close figure was also obtained for the reduced protein (94%). In the latter case, such high values are obtained also thanks to the availability of labeled...

Subsequent to the initial report by Badley et al. two communications appeared, which reported structural investigations on several products obtained from PtCl4 , methyl isocyanide, and hydrazine 33, 117) these compounds had previously been identified (incorrectly) as six-coordinate platinum(II) species 90). In addition, synthesis work in this area was extended somewhat further by these groups. The details of this work presented in these communications and in later full papers 34, 117) are summarized hy Eqs. (17). 

This result also follows from that reported last year where alkyl groups were found to be most favourably bonded to phosphazenyl-phosphorus atoms rather than phosphoryl-phosphorus atoms, and means that revision of a number of previously reported structures is necessary. 

Researchers at Novartis, Senju and Hoffman-La Roche have reported structurally related bicyclic hydroxamic acids as potent PDF inhibitors [106-108]. In 2001, screening efforts at Hoffman-LaRoche identified hydrazide (28)... 

The only reported structure of a stannanimine (entry 4, Table V), shown below, was found to have a trigonal-planar arrangement of the three nitrogen atoms about the tin atom.88 The Sn=N double bond is significantly shorter than the two Sn—N single bonds (1.921(2) versus 2.015(2) and 2.030(3) A). 

A few thioether-ligated copper(II) complexes have been reported, however (cf. Section 6.6.3.1.2) (417) (essentially square planar), (418) (two crystalline forms one TBP and other SP),361 (419) (SP),362 (420) (SP),362 (421) (TBP),362 (422) (SP),363 (423) (SP),363 (424) (two independent complexes SP and octahedral),364 (425) (TBP).364 In the complexes (420) and (421), EPR spectra revealed that the interaction between the unpaired electron and the nuclear spin of the halogen atom is dependent on the character of the ligand present. For (424) and (425), spectral and redox properties were also investigated. Rorabacher et al.365 nicely demonstrated the influence of coordination geometry upon CV/Cu1 redox potentials, and reported structures of complexes (426) and (427). Both the Cu1 (Section 6.6.4.5.1) and Cu11 complexes have virtual C3v symmetry. 

Comba et al. reported structural properties (in the solid state and in solution) and molecular modeling studies on a dicopper(II) complex (545) (SP) of a macrocyclic amide ligand.443 In 1993... 

Although in most of the above reports structural information is based on X-ray data, Au Mossbauer spectroscopy has also been successfully employed for the investigation of two-, three-, and four-coordination in gold(I) complexes.2551 An increase in coordination numbers leads to a decrease in the isomer shift (IS) by 1-2mm s 1 (three-coordination) or 2-4mm s 1 (four-coordination) relative to two-coordination. For the same ligands, the quadrupole splitting (QS) for three-coordinated complexes is expected to be very similar to that for the two-coordinate derivatives, while that for complexes with Td symmetry should be zero. 

The reported structural chemistry of zinc aldehyde complexes is dominated by Vahrenkamp and co-workers. A systematic investigation is reported over three papers published in 1999. All X-ray structures reported in these papers are aryl aldehydes and no aliphatic aldehyde structures with zinc were found in the CSD. Zinc is frequently exploited in preparative organic chemistry and enzyme-catalyzed transformations of organic carbonyl compounds. 

Diazaphospholes constitute the most widely investigated class of heterophospholes, the 67t-aromatic phosphorus heterocycles [1,2]. Diazaphospholes are unique in the manner that the five-membered ring incorporates one phosphorus atom. First diazaphosphole representative, i.e. 2//-[l,2,3 diazaphospholc was obtained as early as 1967 [3] and until 1980s the interest of organophosphorus chemists remained in the development of different synthetic routes and in investigating their varied reactivity due to the structural diversity within the class [4], On the basis of the relative positions of the three heteroatoms in the five-membered ring, six monocyclic diazaphosphole systems (A-F) are possible and all of them have been reported (Structure 1). 

The effect of the cluster size on the energy profile was calculated by comparing the first elementary steps of the N20 decomposition reaction route considering the two clusters (Z) and (Z0H). In Figures 2i. and 2ii, the calculated energy profiles for the adsorption and dissociation steps (equations 1 and 2), occurring over [Fe (p-0)(p-OH)Fe]+ inserted in part of the zeolite framework Z and Z 0H respectively, are reported. Structures (a), (b) and (d) correspond to local minima on the PES, whereas structure (c) represents the TS for N20 dissociation. 

Far fewer structural studies have been conducted for the alkali metal chalcogenolates Se-M and Te-M. Nevertheless, the general aggregation patterns emerging are similar to those for S-M complexes, with solvated monomers and ring dimers being the dominant aggregation states for the reported structures.404... 

Reported structures for homobifunctional aryl azides include a biphenyl derivative and a naphthalene derivative (Mikkelsen and Wallach, 1976), a biphenyl derivative containing a central, cleavable disulfide group (Guire, 1976), and a compound containing a central l,3-diamino-2-propanol bridge between phenyl azide rings that are nitrated (Guire, 1976). The only commercially available homobifunctional photoreactive crosslinker is BASED. 

Other donor systems. Although not as common as all-nitrogen donor rings, macrocycles incorporating sulfur donor atoms have been widely reported. Structures (42)-(45) illustrate four representative examples of this type. 

The crystal structures of five 5,6-disubstituted benzofurazan 1-oxides were compared with five previously reported structures three polymorphs of 5,6-dichlorobenzofurazan 1-oxide plus 4,5-dichloro- and 4,5-dibromophthalic... 

Most of the reported structurally characterised neutral spoke C.-T. adducts have sulfur as the donor atom and di-iodine as the acceptor molecule.1,2 10 12 13 18,28 38 Those obtained from molecules containing selenium and di-iodine are less numerous,1,2 39 40... 

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