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Titanium(III) and copper(II) salts of various dialkyl phosphoric acids have been prepared. Molecular weight measurements on the copper(II) dialkyl phosphates show that they are monomeric in ethanol but aggregate to dimeric forms in chloroform, and to trimeric and tetrameric forms in dichloro- methane, while copper(II) di(2- ethylhexyl) phosphate reaches a molecular weight corresponding to a pentamer in n-hexane. Magnetic susceptibility measurements indicate the absence of strong exchange coupling in the copper(II) dialkyl phosphates. E.s.r. measurements have been made on the titanium(III) dialkyl phosphates doped into the corresponding indium(III) dialkyl phosphates. Similar measurements have been made on the copper(II) dialkyl phosphates doped into the corresponding cadmium dialkyl phosphates. E.s.r. measurements have been carried out on chloroform and dimethylformamide solutions of the copper(II) dialkyl phosphates and the triplet state spectra observed at 77 K used to extract the magnetic and structural parameters associated with the dimeric forms of the copper(II) dialkyl phosphates. Infrared spectral measurements have been made on the titanium(III), indium(III), copper(II) and cadmium(II) dialkyl phosphates and the major peaks assigned.

The magnetic susceptibility of (N-2-pyridylsalicylaldiminato)copper(II) nitrate and chloride has been measured at room temperature and 97 K. Contrary to results reported previously we find no evidence for the presence of magnetic exchange interactions in these compounds. Electron spin resonance spectral data on the ethanol-dimethylformamide solutions of the chelates show that the chelates are monomeric in the liquid phase but largely in dimeric form in frozen solution. Computer simulation of the experimental e.s.r. spectra due to the dimeric form has enabled a determination of the symmetry arrangement and structural properties of the pair system to be made.

X-band e.s.r. measurements of aqueous solutions containing titanium(III) trichloride at room temperature and 77 K provide evidence for the formation of aquated Ti(OH)2+ as the major product of hydrolysis at low pH, along with dimeric species Ti2(OH)24+ formed in small amounts. When certain organic solvents miscible with water are present a further hydrolytic product suggested to be Ti2(OH)5+ is found at low pH. Consideration of an interaction spin Hamiltonian which takes into account the symmetry properties of the paramagnetic ion pair systems makes possible the computer simulation of the experimental spectra due to the dimeric species. By this procedure the magnetic parameters associated with the titanium(III) dimers have been evaluated along with a determination of the titanium(III)-titanium(III) ion separations. This information has been used to suggest possible structures for the dimeric species.

Potentiometric pH-titration and electron spin resonance studies have shown the existence of mono-meric, dimeric and dinuclear vanadyl chelates of certain polyaminocarboxylic acids. The ligands studied include ethylenediaminetetraacetic (edta), ethyleneglycolbis(β- aminoethyl ether)-N,N?-tetra-acetic (egta), diethylenetriaminepentaacetic (dtpa) and triethylenetetraaminehexaace- tic (ttha) acids. All the ligands form 1 : 1 chelates. The addition of ethylene glycol to the aqueous solution in each case provides circumstances for the study of the monomeric chelates, though it is not equally effective in all cases. The 1 : 1 vanadyl egta chelate above pH 5.5 gave rise to ΔMS = 2 and ΔMS = 1 transitions from which structural and magnetic parameters have been determined and interpreted in terms of the formation of a dimeric form of a hydrolytic product of the 1 : 1 chelate. Firm evidence for the formation of dinuclear chelates occurs only in the vanadyl ttha system. Here the room tem- perature e.s.r. spectrum shows the presence of weak exchange coupling between the vanadyl ions in the dinuclear chelate.

The X-band e.s.r. spectra due to the copper(II) chelates of the thiosemicarbazones salicylaldehyde thiosemicarbazone (stsc), salicylaldehyde 4-methyl(thiosemicarbazone) (smtc), salicylaldehyde 4- ethyl-(thiosemicarbazone) (setc), salicylaldehyde 4- phenyl(thiosemicarbazone) (sptc), 2-hydroxyacetophen- one 4- ethyl(thiosemicarbazone) (aetc) and 2-hydroxypropiophenone 4- ethyl(thiosemicarbazone) (petc) dissolved in various organic solvents have been studied at room temperature and down to 77 K. The e.s.r. spectra show evidence of hyperfine structure due to the 14N nucleus of the ligand. Addition of the nickel(II) chelate of the thiosemicarbazone ligands to organic solvent solutions of the corresponding copper(II) chelate brings about a profound change in the e.s.r. spectrum of the copper(II) chelate in frozen solution. These changes are interpreted as arising from a change in the ground state of the copper(II) ion from essentially dx2-y2 to d3z2-r2, which arises as a result of specific solute- solute interactions between the copper(II) and nickel(II) chelates.

In contrast to the copper(II) salts of dialkyl phosphates, the analogous aryl compound, bis(diphenyl phosphato)copper(II), forms a dimethylformamide solvate which may be doped into the corresponding cadmium compound. Under these circumstances, the e.s.r. spectrum of the dimethylformamide solvate of bis(diphenyl phosphato)copper(II) at -140C shows signals attributed to superhyperfine coupling between the 31P nucleus of the ligand and the copper(II) ion. The magnetic parameters have been determined.

The existence of mononuclear and dinuclear chromium(III) chelates of triethylenetetraaminehexa-acetic acid (ttha) in aqueous solution has been demonstrated by potentiometric pH titration and electronic visible spectroscopy. The isolation of mononuclear, dinuclear and heteronuclear chromium(III) chelates of ttha has been accomplished. Magnetic susceptibility measurements on the isolated solids point to the absence of magnetic exchange coupling in the dinuclear chromium(III) chelate and in the heteronuclear chelate containing chromium(III) and copper(II). However, the differences in the e.s.r. spectra of the mononuclear and dinuclear ttha chelates observed in frozen aqueous solution may arise from some form of magnetic dipolar coupling between the chromium(III) ions in the dinuclear chelate.

The e.s.r. spectra of frozen aqueous solutions containing vanadyl (DL)- and (DD)-tartrates are consistent with the formation of dimeric species. Computer simulation of the spectra, assuming a monoclinic dimer model, has enabled the determination of the magnetic parameters associated with vanadyl ions, the internuclear separations between the metal ions in the dimers and their relative orientation. For vanadyl (DL)-tartrate dimer, the excellent agreement between structural parameters for the solid and frozen glass was taken to indicate that the same structure exists in both states. In the case of vanadyl(DD)-tartrate, however, although the overall symmetry is maintained, a slight reduction in the vanadyl vanadyl separation is believed to occur as a result of incorporation into an ethylene glycol-water glass.

An introduction to soil mechanics limitations, testing concerns, and deposition of collapsible soil from the arid western states in the U.S. is presented. Laboratory evaluation of their properties for routine foundation engineering bearing capacity and settlement is of limited use. In situ testing is shown to be practical and successful in a wide range of soil types from uniform fine-grained soils to silty-sandy gravels. The hydraulic, monocell, prebored pressuremeter is proposed as an in situ test to establish dry, wet, and dry-wet geotechnical parameters for design by three testing procedures. Each procedure is given a detailed description, typical results are presented for collapsible debris fan deposits, and application of the procedures to routine foundation design is discussed. Simple collapse categories are introduced based on the pressurementer stiffness change from dry to wet conditions. Two minor modifications to the commercial pressuremeter probe end shoe and top support collar are recommended to ensure uniform radial water migration. Estimates of the depth of collapse from subsurface soil beneath existing foundations undergoing excessive settlement are also possible.

A control unit for hydraulic single-cell pressurementers is described which employs multiple cylinders. The basic control unit can function with a single cylinder for small low-capacity pressuremeter probes and with additional cylinders added to increase the system capacity to serve larger probes. The unit described is portable, rugged, lightweight, and cost effective.Comparative pressurementer test results are given for the multicylinder control unit (PUP) and the commercial hydraulic unit (TEXAM), with both units serving a 32-mm-diameter EX probe and a 60-mm-diameter BX probe.

The incidence of drug and chemical related deaths was studied over a six-year period in the State of Maryland. Deaths were classified into the following categories: alcohol, carbon monoxide (CO), single drugs, multiple drugs, and narcotism. The last three categories were further subdivided as to the specific drugs or chemicals involved. Over the six-year period the number of alcohol and CO deaths remained steady, the number of barbiturate and propoxyphene deaths declined, while the number of tricyclic antidepressant drug deaths increased.

The triplet state e.s.r. spectra of bis(dimethylglyoximato)copper(II) in ethanol solutions have been recorded and the results interpreted in terms of a magnetic dipole-dipole interaction between pairs of copper(II) ions in a dimeric complex. Consideration of a spin Hamiltonian which takes into account the symmetry relationship of the transition metal ions in the dimeric complex has provided a set of structural and magnetic parameters by computer lineshape simulation procedures. The results indicate that the symmetry of the pair system is similar to that observed for the dimeric units in the solid complex but that the calculated distance between the metal ions is somewhat larger than that determined by crystallographic methods for the solid complex.

Measurements of 27Al nuclear magnetic resonance of aqueous solutions containing aluminium chelates of hydroxy carboxylic acids show that the signal intensity depends to a marked extent on the pH of the solution. This effect has been interpreted in terms of polymerization of the aluminium chelates which results in a broadening of the signal through magnetic dipole-dipole coupling between the various 27Al nuclei.

The electron spin resonance spectra of copper(II)- tris(hydroxymethyl)amino-methane complexes in aqueous solution provides evidence of the formation of dimeric species. These species are found to be different from those postulated by previous investigations. In dimethylformamide dimeric species are formed at room temperature and frozen solution in 1 : 1 and 1 : 2 metal-to-ligand mole ratios, though the formation of the dimer is critically dependent on the addition of base. Low field, ΔM = 2, signals observed for these systems have been interpreted in terms of dipole-dipole coupling between pairs of copper(II) ions. Structures for the copper(II) dimers have been proposed which are compatible with the copper-copper separation estimated by computer simulation of the spectra.

Electron spin resonance measurements have been made on the copper(II) chelates of o-methylmercaptobenzoic acid, S-carboxydiethyldithiocarbamic acid, thiazolidine-4-carboxylic acid, 5-hydroxy-1,3-benzoxathiol-2-one and diacetyl bisthiosemicarbazone. The e.s.r. spectra of dimethylformamide solutions of the chelates have been interpreted in terms of dimeric species which are believed to exist at room temperature, as well as in frozen solutions in the case of o-methyl-mercaptobenzoic acid, S-carboxydiethyldithiocarbamic acid, and 5-hydroxy-1,3-benzoxathiol-2-one, whereas the dimeric forms of the remaining chelates are formed solely in frozen solution. The results have been interpreted as arising from dipole-dipole coupling between the copper(II) ions in their dimeric forms, and a line simulation procedure employed to extract the distance between the copper(II) dipoles. This information has been used to suggest the possible structures of the dimeric species. The effect of the introduction of zinc(II) ions during the formation of the copper(II) chelates has been assessed in each case.

Autooxidation of tin(II) in citric acid-sodium citrate solutions has been studied and the rate of oxidation was described by a rate law first order in tin(II) concentration. The oxidation is inhibited by relatively small concentrations of nitrate ion though nitrate is not consumed in the reaction. It has been found that during the oxidation of tin(II) to tin(IV) keto-acid breakdown products of citric acid are formed and that their presence is critical in overcoming the inhibiting effect of the nitrate ion.