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Research describes the syntheses of an array of N-substituted-tach-Cu(II)-dihalide complexes and the cognate tach ligands together with their solid-state and solution structure. Results discuss the Cu(II) complexes of N,N',N'-trialkyltach derivatives of cis,cis-1,3,5-triaminocyclohexane.

Results describe the structural data on tetramethylsuccinamide and its complex with lanthanide nitrates and relate the solid-state structures to solution state conditions.

The unique hexadentate chelator tachpy contains the cis-1,3,5-triaminocyclohexane framework with N-pendant 2-pyridylmethyl arms and forms Ga3+ and In3+ complexes. The solid-state structures of the M(tachpy)3+ units indicate a distortion of the coordination sphere toward trigonal prismatic from octahedral as the metal radius increases. Ga(tachpy)3+ is inert to aqueous hydrolysis over the pH range 2-8 while In(tachpy)3+ hydrolyzes immediately under these conditions.

Tetraaza macrocycle complexes, (Me4taen)Zr(O(super t)Bu)2 (4) and (Me4taen)Hf(NMe2)2 (5), crystallize in triclinic space groups, and have a cis stereochemistry. The central metal atom has a distorted octahedral metal geometry. (Me4taen)ZnCl2 (1) and (Me4taen)Zr(CH2Ph)2 (2) have trigonal prismatic structures. The complexes 1 and 2 have no pi-component in the M-X covalent bond. The electronic characteristics help in determining the structures of these (Me4taen)MX2 species.

Six new poly(ethylene glycol) (PEG) complexes of PbBr2 and Pb(NO3)2 with five- to eight-donor PEGs were generated and characterized by crystallography. (Pb(NO3)2(EO4))n, (Pb(NO3)2(EO5)), and (Pb(NO3)2(EO6)) crystallize as tight ion pairs with the PEG ligands coordinating in a equatorial plane around the Pb2+ ions. (PbBr(EO5)(mu-Br)PbBr2)*H2O, (PbBr(NCMe)(EO6))2(PbBr2(EO6))(PbBr3)2, and (PbBr(EO7))(PbBr3) crystallize as PEG-mediated coordination polymers.

A preorganization approach was used in the synthesis of a cyclohexylene analogue of DTPA, N-(2-aminoethyl)-trans-1,2-diaminocyclohexane-N,N',N'- pentaacetic acid (H5CyDTPA) and its C-functionalized version for antibody conjugation. Conformational preorganization is responsible for the shorter Bi-O and Bi-N bond lengths of Bi(CyDTPA)(super 2-) compared to Bi(DTPA)(super 2-). The preparation of H5CyDTPA and the synthesis and structural characterization of bismuth (III) complexes of CyDTPA(super 5-) and H2DTPA(super 3-) are described.

Previous research has established a binding mode for transition metal ion complexes in lanthanide species. A similar binding mode is established for transition metal ion complexes in p-sulfonatocalix(5)arene. It is shown that the calixarene formation is highly mobile and varies according to the steric and electronic needs of the guest. Aromatic hydrogen bonding by included water is not shown, presumably as a result of the calix(5)arene cavity's large size.

Syntheses of nine different directly coordinated complexes involve the stoichiometric reactions of Sr(NO3)2 or SrCl2.6H2O with various polyethylene glycols, in a medium of CH3CN. X-ray crystallographic studies reveal that glycols exhibit similar conformations in all the nine complexes. Glycols favor the formation of pseudocyclized in-cavity crown ether-like complexes. X-ray analysis enables the evaluation of Sr-O (alcoholic) and Sr-O (etheric) separations.

The polyethylene glycols (PEG's) complexes of MCl3.nH2O exhibit total steric control of the primary coordination sphere, and its structure is compared to that of macrocyclic 18-crown-6. The similar features observed between the crystal structures of the species of the pentaethylene glycol (EO5) lenthamid complexes and 18-crown-6 complexation induces the flexible cavity in 18-crown-6. The differences in the structural features arise due to the cyclic and less flexible natures of 18-crown-6 compared to EOS. PEG complexes of MCl3. nH2O are easily isolated due to their flexible nature.

The reaction of MoCl4(dme), where dme = 1, 2-dimethoxyethane, with dme resulted in the novel molybdenum chloride formulated as Mo2Cl6(dme)2. This compound proved to be an effective starting material for the metathetical syntheses of metal-metal triply bonded Mo2X6 complexes and the hexaalkyls Mo2(CH2MMe3)6, where M = C and Si. It was also the precursor of the hexaalkoxides Mo2(OCMe2CH2R), where R = H and Me, and the hexakis(fluoroalkoxide) dimers Mo2(OCMe sub 3-x CF3 x)6, where x = 1 and 2.

The synthesis and structural characterization of the syn and anti diastereomers of Tc/Re complexes of small tripeptide ligands is presented.

Two experimental investigations are performed to investigate the impact of ligand preorganization on lanthanide(III) binding and solution binding affinities are determined through single-phase spectrophotometric titrations. The bicyclic malonamide exhibit 10-100X increased binding affinity compared to the cyclic malonamides.

The metal-ion complexing properties of the ligand EDTAM (ethylenediamine-N,N,N'N'-tetraacetamide) are investigated as a model for the role of amide oxygen donors in the binding sites of Ca-binding proteins. This resembles the metal-ion affinity patterns of binding sites in Ca-selective proteins for large metal ions, where amide oxygen donors are present.

Raman spectra of a number of triply bonded M(sub 2)X(sub 6) (M=Mo, W; X= alkoxide, alkyl) compounds are obtained. Computational results suggest that a Vm=m band may be present in the published spectra of the M(sub 2)(NMe2)(sub 6) pair.

Research has been conducted on uranyl nitrate complexes frormed in hydrophobic ionic liquids. The authors report their study of inner-sphere coordination environments observed for these complexes.

An experiment is conducted to prepare the hexadentate ligand, which involves a six step process. Copper(II), palladium(II), and cobalt(II) complexes, are obtained from the reactions of H3tachta with the corresponding metal chlorides.

Compounds formed from the reaction of N,N,N',N'-tetramethylsuccinamide (TMSA) with trivalent lanthanide salts possessing the poorly coordinating counteranions triflate (CF3SO(sub 3)(super -)) and perchlorate (ClO(sub 4)(super -)) have been prepared and examined. IR spectroscopy studies in anhydrous acetonitrile suggest that the solid-state structures of Ln-TMSA compounds are maintained in solution.

A feature of trinuclear oxo-centered metal complexes of the general formula [M3O(OOCR)6L3] that has gained attention is their failure to adopt the expected 3-fold symmetry when the three metal atoms are identical and in a similar state of oxidation. Crystallization of the compound [Cr3O(OOCPh)6(py)3](py)ClO4 results in a threefold symmetrical lattice with the trichromium clusters forming equilateral triangles. Details of the study are presented.

Research was conducted to examine the chemical speciation of the uranyl ion under highly alkaline conditions. Tetramethylammonium countercation was used to prevent the precipitation of uranate salts which allowed for the study of uranyl hydroxide complexes under highly alkaline solution conditions. Results indicate that an equilibrium exists between two species, assigned to UO2(OH)(sub 4)(super 2-) and UO2(OH)(sub 5)(super 3-).