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The synthesis and structural characterization of [alpha]-diimine iron complexes which contain intermediate spin-state iron centers is described.

The synthesis of a range of porphyrazines bearing several alternative peripheral multidenate ligands including vicinal di-(2-hydroxy-2-methylpropanamido), di-(2-methoxy-2-oxo-acetamido), di-(2-pyridine-carboxamido) and di-(2-quinolinecarboxamido) units were reported. The polydentate ligands were converted into bimetallic complexes and tetrametallic porphyrazine dimer complexes.

The new imino sulfinamidine ligand PhS(NHtBu)=NC(Me)=N(C6H3-2,6-Pr20, LH is synthesized from readily available reagents. The ligand is employed in the synthesis of mononuclear Zn(II) and Al(III) alkyl complexes, which are structurally characterized by X-ray crystallography.

A series of iron(ii) bis(triflate) complexes containing tripodal tetradentate nitrogen ligands with pyridine and dimethylamine donors of the type [N(CH2Pyr)(sub 3-n)(CH2CH2NMe2)n] [n=0 (tpa, 1), n=1 (iso-bpmen, 3), n=2 (Me4-benpa, 4), n=3 (Me6-tren, 5)] and the linear tetradentate ligand [(Ch2Pyr)MeN(CH2CH2)NMe(CH2Pyr), (bpmen, 2)] are prepared. The catalytic properties of the complexes for the oxidation of alkanes are evaluated using cyclohexane as the substrate.

A description on the fusion and structural features of two new titanium guanidinate complexes is presented. In addition, the creation of titanium carbonitride from two titanium guanidinate complexes through low-pressure chemical vapor deposition is also examined.

In the presence of chloride or bromide, nickel(II) and Hatu [Hatu = H2NC(=NH)NHC(=S)NH2] assemble to yield the metallacages [Ni6(atu)8X][ClO4]3 (atu = deprotonated form of Hatu; X = Cl, Br). The synthesis of the cages depended to a great extent on the nature of the anions and the solvents used.

Research has been conducted on the niobium thiolate complexes. The synthesis and structural characterization of these complexes have been carried out and the use of single source precursor in preparing niobium sulfides via the thio thio 'sol-gel' and vapor phase thin-film experiments is described.

Research has been conducted on the ability of the ambidentate to form polymeric network complexes. The results of the X-ray characterization of the homometallic copper and heterometallic cobalt/dysprosium complexes are reported.

Research has been conducted on the gallium silylamido complexes. The synthesis of these complexes has been carried out and the results indicate that the formation of the [PhGa{N(SiMe (sub)2 Ph) (sub)2}(mu-Cl)] (sub)2 and [MeGaCl (sub)2] (sub)2 compounds are the product of the phenyl and methyl group transfer from the amide's silyl group to the gallium center.

The differences in the formation of polymeric lanthanide complexes with different ligands indicate that steric requirements play a role in the polymer formation. Data indicate that the lanthanum atom adopts a monocapped square antiprismatic geometry with coordinating metal atoms.

Results demonstrate that the structural framework of hexamethylenebis(acetamide) (HMBA) involves transfer of anions facilitating octahedrally coordinated 'node' points of HMBA-linked cations and the highly charged counteranions of suitable size and shape in the framework 'voids'.

The synthesis and x-ray structural characterization of Mn, Co, Cu, Ni, and Zn compounds with monosubstituted diphenylaminosquarate ligand are described. All are polymeric except for the nickel compound, which exists as a simple salt.

Research has been conducted on the europium(III) ion that has two bridging and two pendant phenylsquarate ligands. The emission spectra of the polymeric complex is examined.

Research was conducted to examine the first series of lanthanide complexes with a monosubstituted squarate ligand, 3-diphenylamino-4-hyydroxycyclobut-3-ene 1,2-dione (diphenylaminosquarate). Three of the complexes were isomorphous and dimeric and have both bridging and pendant diphenylamiosquarate ligands while the fourth was monomeric. The sterically hindered diphenylamino substituent was observed to be resistant to the hydrolysis previously seen with the corresponding dialkylamino analogues.

Research was conducted to examine the first-row transition-metal complexes of the 1-methoxycyclobutenedionate(1-) ion to gain an insight into the nature and extent of electron delocalization on the C4-rings in complexes of the ligand and their complexing properties. Results suggest that the nature of the substituent on the ligand ring affects the extent of delocalization on the ring. The synthesis and characterization of several first-row transition metal complexes of the monosubstituted squarate ligand are described.

Isomorphous polymeric complexes of formula M(CH3C4O3)(NO3)(H2O)4.2H2O that crystallized in the monoclinic space group P2(sub 1)/m (No. 11) with, a=6.409(5) angstroms, b=14.717(10) angstroms, c=7.259(6) angstroms, beta=114.73(4) degrees, and Z=2 were the product of the reaction of 1-methylcyclobutenedione with M(NO3)2.xH2O (M=CO and Ni). In both cases, adjacent metal centers were bridged mu-1,3 by the 1-methylcyclobutenedione ligand, which exhibited distinct multiple bond localization. The positive charges on the polymer chains were balanced by nitrate ions.

Research was conducted to examine five polymeric framework arrays that result from the reaction of bis(amides) of the type CH3CONH(CH2)(sub n)NHCOCH3 with a range of manganese(II) and cobalt(II) salts using X-ray crystallography. The objective was to determine whether representative members of HBMA complexes had network structures. Results of preparations of other transition-metal complexes with the ligands are described.

A study showed that tetramethoxyborate anions are potentially versatile general synthons for one-dimensional compounds. Self-assembly of lanthanide(III), salicylaldehyde, sodium and tetramethoxyborate species resulted in a novel ionically linked sinusoidal chain. Tight crest-in-trough packing of the sinusoidal chains caused a multidimensional energy transport while positional switching of Eu and Na cations produced intriguing luminescence characteristics.

Research was conducted to examine the reactions of the homoleptic alkoxides (M(OPr(super i))4*(Pr(super i)OH)) (M = Zr or Hf) using various stoichiometric amounts of the beta-diketone ligand tmhd-H (2,2,6,6-tetramethylheptane-3-5-dione). The compound, (Zr2(OPr(super i))6(tmhd)2), was successfully isolated and structurally characterized. Results demonstrate that the use of the dimer eliminates some of the problems found in growth experiments with simpler metal alkoxides or beta-diketonates.

4,4'-bipyridine is used as a bridging ligand between metal centers. The syntheses have been undertaken of 'extended reach' ligand 2,3,5,6-tetrafluoro-1,4-bis(2-pyridylsufenyl)benzene (L), its 4-pyridylsulfenyl analogue (L2) and complex Cu(L(super1))C1(sub2).2CHC1(sub3) (1) and complex (Cu(Lu(super2))(DMF)Br(sub2)).DMF (2). The polymeric structure of (1) has a trans-planar CuC1(sub2)N(sub2) coordination geometry. The DMF molecule in (2) is bonded in an apical site above a trans-CuBr(sub2)N(sub2) unit.

Research was conducted to examine the synthesis, structure and luminescence behavior of new stoichiometric crown ether compounds of Mn2+ in well-defined coordination environments. The objective was to gain an insight into the origin of emitting crystal defects observed in cubic F23 crystals. Results indicate that emission from the sandwich species (Mn-(12C4)2)2+ is strongly sensitized via fast MnBr4(super 2-)-to-(Mn-(12C4)2)2+ energy transfer for T = 10K but back (Mn(12C4)2)2+-to-MnBr4(super 2-) energy transfer is also active, especially for T > 120 K.

Research was conducted to examine the hypothesis that dithiocarbamate-functionalized dendrimers act as ligands for metal complexes. The methodology used was based on the use of the well-known and well-characterized poly(amido)amine dendrimers to provide the structural framework for the molecules. Results demonstrate the synthesis of dithiocarbamate-terminated dendrimers and their subsequent reactions to form ruthenium dithiocarbamate complexes.

The manganese(III) porphyrazine complexes (Mn(Et2dtc)ODMAPz) and (Mn(Cl)ODMAPz) have eight peripheral dimethylamino groups attached to the beta-carbon atoms of the pyrrole rings. This was gleaned from the syntheses and determination of the X-ray crystal structures of the two complexes. Electrochemical data also reveal that the complexes are electron-rich and are an extremely strong reductant, while magnetic susceptibility measurements showed an S = 2 ground state with axial zero-field splitting.

A study was conducted on the use of steric shielding to facilitate the possible formation and/or stabilization of an alkylidyne iron complex. The results led to the synthesis of the bis(mu-aroyl) bimetallic complex [Fe2(mu:sigma,sigma'-OCC6H3Me2-2,6)2(CO)5(PPh3)] as well as the preparation of the related bis(carbamoyl) analogue [Fe2(mu:sigma,sigma'-OCNiPr2)2(CO)5(PPh3)] through a number of complementary routes.

The effects of the three 1-(dialkylamino) derivatives of 3,4-dihydroxycyclobut-3-ene-1,2-dione ligands on the complexing properties when amino substituents of increasing R size were substituted on the ring were analyzed. Nuclear magnetic resonance and crystallographic studies revealed that the lead atom was an eight-coordinate, had a square moiety, bidentate and binucleating.

Three optically pure P-chiral diphosphines were efficiently synthesized by the palladium-complex-promoted asymmetric Diels-Alder reaction of 1-phenyl-3,4-dimethylphosphate with diphenylvinylphosphine, (E)-diphenyl-1-propenylophosphine and (Z)-diphenyl-1-propenylophosphine, respectively. (S)-(1-(dimethyllamino)ethyl)naphthalene was used as the chiral auxilliary in the reaction. The diphosphines were observed to be highly air-sensitive in the free ligand and powerful sequesters of group 8 metals.

Group 4 metal complexes containing two bidentate ligands combining phenoxide and tertiary phosphine donors are investigated. Bis(phosphanyl(phenoxide) complexes of the group 4 metals, upon activation by methylaluminoxane, are highly active for ethylene ad propylene polymerization.

Research has been conducted on the dithiophosphinato complexes use as solvent extraction agents for metals, insectides and pesticides. The X-ray crystal structures of tris(diisobutyldithiophosphinato)gallium(III) and -indium(III) compounds have been investigated, and the results indicate that these compounds do not exhibit different coordination modes.

A study was conducted on the formation of an unusual and structurally characterized metallacyclic thioketene complex [Mo-{eta2-kappa(C,S),sigma-kappa(S')-S=C=CRC(=O)S}(=O){HB-(pz)3}] from the reactions of two alkylidynemolybdenum complexes with carbon disulfide. The findings result in the reinterpretation of previous alkylidyne/CS2 coupling processes.

An organopalladium reaction promoter catalyzes the asymmetric Diels-Alder reaction between phenyldivinylphosphine and 1-phenyl-3,4-dimethylphosphole to produce both the enantiomerically pure forms of a rigid diphosphine ligand. X-ray analysis of this ligand reveals five new chiral centers with S and R absolute stereochemistries at two phosphorus and three carbon stereogenic centers. The regiospecific coordination of phenyldivinylphosphine to the diphosphine ligand complex in dichloromethane gives monomeric complexes as stable yellow prisms in 80% yields.

The article discusses the synthesis, structure, as well as the properties of the various imidazolium-2-dithiocarboxylate compounds. The results prove that these compounds can be easily used for the formation of numerous gold(I) complexes and gold nanoparticles.

The synthesis, characterization and polymerization studies of a series of new bis(phosphinic)diamido yttrium complexes are reported. The complexes are found be to adopt dimeric structures in both solution as well as in the solid state and are highly active species for lactide ring-opening polymerization.

The synthesis and the formation of mono- and bis-chelates in various magnesium and zinc complexes are studied. The ligands show a greater resistance towards bis-chelation due to presence of more N-aryl substituents.

The synthesis of a series of iron(II)-bis(triflate) complexes [Fe(L)[(OTf).sub.2]] containing linear tetradentate bis(quinoyl)-diamine and bis-(quinolylmethyl)-diamine ligands with a range of ligand backbones is described. The increased flexibility in the ligand has resulted in a weaker ligand field and the activity and selectivity of the catalysts are related to the strength of the ligand field and the stability of the catalyst.

A description is provided of highly active ethylene polymerization catalysts supported by tridentate phenoxyamide ligands. It is shown that the incorporation of halo substituents within the amino aryl units leads to catalysts with dramatically improved ethylene polymerization activities and excellent 1-hexene incorporation.

The reaction between CuCl2, Cu(OAc)2, and CuSO4 and two different bipyridylurea ligands are conducted and the crystal structures of the resulting metal-organic assemblies are determined. The results demonstrate that the geometry and the size of the anions together with their coordinating and hydrogen bonding properties are essential in determining the final structures of the assemblies.

A series of novel polyiron species are prepared from the reaction of iron chloride with the 2,5-disubstituted pyridines H2L(super n) (H2L(super 1) = N,N'-bis(n-butylcarbamoyl)pyridine-2,6-dicarboxamide, H2L(super 2) = N,N'-bis(n-ethylcarbamoyl)-pyridine-2,6-dicarboxamide). The five complexes demonstrate the versatility that the new ligand has as a building block for the formation of supramolecular coordination assemblies.