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Although abundant in organic molecules, carbon-hydrogen (C-H) bonds are typically considered unreactive and unavailable for chemical manipulation. Recent advances in C-H functionalization technology have begun to transform this logic, while emphasizing the importance of and challenges associated with selective alkylation at a sp.sup.3 carbon.sup.1,2. Here we describe iron-based catalysts for the enantio-, regio- and chemoselective intermolecular alkylation of sp.sup.3 C-H bonds through carbene C-H insertion. The catalysts, derived from a cytochrome P450 enzyme in which the native cysteine axial ligand has been substituted for serine (cytochrome P411), are fully genetically encoded and produced in bacteria, where they can be tuned by directed evolution for activity and selectivity. That these proteins activate iron, the most abundant transition metal, to perform this chemistry provides a desirable alternative to noble-metal catalysts, which have dominated the field of C-H functionalization.sup.1,2. The laboratory-evolved enzymes functionalize diverse substrates containing benzylic, allylic or [alpha]-amino C-H bonds with high turnover and excellent selectivity. Furthermore, they have enabled the development of concise routes to several natural products. The use of the native iron-haem cofactor of these enzymes to mediate sp.sup.3 C-H alkylation suggests that diverse haem proteins could serve as potential catalysts for this abiological transformation, and will facilitate the development of new enzymatic C-H functionalization reactions for applications in chemistry and synthetic biology.Evolved iron-containing enzymes based on cytochrome P450 achieve selective intermolecular alkylation of sp.sup.3 C-H bonds through a carbene C-H insertion strategy., Author(s): Ruijie K. Zhang [sup.1] , Kai Chen [sup.1] , Xiongyi Huang [sup.1] , Lena Wohlschlager [sup.1] [sup.2] , Hans Renata [sup.1] [sup.3] , Frances H. Arnold [sup.1] Author Affiliations:(1) [...]

A stable colloidal solution of gold nanoparticles (AuNPs) has been prepared in tetrahydrofuran by gas reduction of AuCl(tetrahydrothiophene) and alkylamines (1-octylamine,1-dodecylamine, and 1-hexadecylamine) as stabilizing agents. Carbon monoxide is a better reducing agent than hydrogen. The important parameters for control of the synthesis of AuNPs are the temperature, the molar ratio of ligand/metal, and the structure of the stabilizing agent. A high concentration of long alkyl chains (10 eq.) favours the control of the growth of AuNPs of defined size and shape with a diameter of 4.7 nm and a narrow size distribution. For the first time, liquid-state combined with solid-state NMR spectroscopies were used in order to determine the role of the long chain alkylamines in the synthesis of AuNPs in CO atmosphere. This combination enables the understanding of the complex chemistry of the surface of AuNPs involved in the stabilization of the AuNPs. Indeed, carbamide species were formed during the synthesis. They were strongly coordinated to the surface of AuNPs and exchange phenomena of the alkylamines present in solution occurred, too. Keywords Au(I) precursor. Organometallic synthesis. Gold nanoparticles. NMR spectroscopy, Introduction Since the 1990s, the formation of self-assembled nanostructures and the deposition of metallic nanoparticles (MNPs) have been the subject of growing interest. MNPs are now commonly used in many [...]

Allosteric regulation of organometallic catalysts could allow for greater control over reactions. We report an allosteric supramolecular structure in which a monometallic catalytic site has been buried in the middle layer of a triple-layer complex. Small molecules and elemental, anions can open and dose this complex and reversibly expose and conceal the catalytic center. The ring-opening polymerization of [epsilon]-caprolactone can be turned on by the in situ opening of the triple-Layer complex and then completely turned off by reforming it through the abstraction of [Cl.sup.-], the allosteric effector agent, without appreciable Loss of catalytic activity. This process can regulate the molecular weights of the resulting polymers. 10.1126/science.1193928

In the present work, metallomics studies using biomolecular (matrix-assisted laser desorption ionization time-of-flight tandem mass spectrometry, MALDI-TOF MS/MS) and elemental mass spectrometry (laser ablation inductively coupled plasma mass spectrometry, LA-ICPMS) of human blood serum samples from bipolar disorder (BD) patients compared to controls were performed. The serum samples from three different groups: control (n = 25), BD patients treated with Li (n = 15), and BD patients not treated with Li (n = 10), were pooled according to their groups and separated by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). Then, in order to determine the metals bound to the protein spots and search for differences among the studied groups, the 2-D gels were analyzed by LA-ICPMS in three distinct modes: bioimaging of metals in gel sections, line scan through the protein spots, and microlocal analysis of selected protein spots. MALDI-TOF MS/MS characterized 32 serum proteins, and they were associated with the metals previously detected. When comparing control and treated BD patient groups, a differentiation in terms of metals bound to proteins was possible to observe. The main metals bound to proteins found in all groups were Na, Mg, Tin, Ca, and Fe. Mn was only detected in the control group; Co was only observed in the control and BD patients treated with Li group. K and Ti were only found in the BD patient groups, and P was only observed in control and BD patients not treated with Li drugs. This exploratory work shows that the association of LA-ICPMS with MALDI-TOF MS/MS is a powerful strategy in metallomics studies applied to determine differences in metal-containing proteins, being able to play an important role on the discovery of potential markers for BD and its treatment with Li in serum samples. 10.1021/ac101063t

We report the results of a series of chemical, EPR, ENDOR, and HYSCORE spectroscopic investigations of the mechanism of action (and inhibition) of GcpE, E-1-hydroxy-2-methyl-but-2-enyl-4-diphosphate (HMBPP) synthase, also known as IspG, an [Fe.sub.4][S.sub.4] cluster-containing protein. We find that the epoxide of HMBPP when reduced by GcpE generates the same transient EPR species as observed on addition of the substrate, 2-C-methyl-D-erythritol-2, 4-cyclo-diphosphate. ENDOR and HYSCORE spectra of these transient species (using [sup.2]H, [sup.13]C and [sup.17]O labeled samples) indicate formation of an Fe-C-H containing organometallic intermediate, most likely a ferraoxetane. This is then rapidly reduced to a ferracyclopropane in which the HMBPP product forms an [[eta].sup.2]-alkenyl [pi]-(or [pi]/[sigma]) complex with the 4th Fe in the [Fe.sub.4][S.sub.4] cluster, and a similar 'metallacycle' also forms between isopentenyl diphosphate (IPP) and GcpE. Based on this metallacycle concept, we show that an alkyne (propargyl) diphosphate is a good ([K.sub.i] ~ 300 nM) GcpE inhibitor, and supported again by EPR and ENDOR results (a [sup.13]C hyperfine coupling of ~7 MHz), as well as literature precedent, we propose that the alkyne forms another [pi]/[sigma] metallacycle, an [[eta].sup.2]-alkynyl, or ferracyclopropene. Overall, the results are of broad general interest because they provide new mechanistic insights into GcpE catalysis and inhibition, with organometallic bond formation playing, in both cases, a key role. 4Fe-4S protein | GcpE (IspG) | metallacycle doi/ 10.1073/pnas.1000264107

We have investigated the mechanism of action of Aquifex aeolicus IspH [E-4-hydroxy-3-methyl-but-2-enyl diphosphate (HMBPP) reductase], together with its inhibition, using a combination of site-directed mutagenesis ([K.sub.M], [V.sub.max]), EPR and [sup.1]H, [sup.2]H, [sup.13]C, [sup.31]P, and [sup.57]Fe-electron-nuclear double resonance (ENDOR) spectroscopy. On addition of HMBPP to an (unreactive) E126A IspH mutant, a reaction intermediate forms that has a very similar EPR spectrum to those seen previously with the HMBPP 'parent' molecules, ethylene and allyl alcohol, bound to a nitrogenase FeMo cofactor. The EPR spectrum is broadened on [sup.57]Fe labeling and there is no evidence for the formation of allyl radicals. When combined with ENDOR spectroscopy, the results indicate formation of an organometallic species with HMBPE a [pi]/[sigma] 'metallacycle' or [[eta].sup.2]-alkenyl complex. The complex is poised to interact with [H.sup.+] from E126 (and H124) in reduced wt IspH, resulting in loss of water and formation of an [[eta].sup.1]-allyl complex. After reduction, this forms an [[eta].sup.3]-allyl [pi]-complex (i.e. containing an allyl anion) that on protonation (at C2 or C4) results in product formation. We find that alkyne diphosphates (such as propargyl diphosphate) are potent IspH inhibitors and likewise form metallacycle complexes, as evidenced by [sup.1]H, [sup.2]H, and [sup.13]C ENDOR, where hyperfine couplings of approximately 6 MHz for [sup.13]C and 10 MHz for [sup.1]H, are observed. Overall, the results are of broad general interest because they provide new insights into IspH catalysis and inhibition, involving organometailic species, and may be applicable to other [Fe.sup.4][S.sup.4]-containing proteins, such as IspG. enzyme inhibition | iron-sulfur protein | isoprenoid biosynthesis | nonrnevalonate pathway www.pnas.org/cgi/doi/10.1073/pnas.0911087107

Compared with the enormous arsenal of catalysts used to produce organic compounds, complementary species that are able to mediate sophisticated organometallic transformations are virtually nonexistent. We found that stable N-heterocyclic carbenes (NHCs) can mediate unusual organometallic transformations in solution at room temperature. Depending on the choice of NHC initiator, stoichiometric or catalytic reactions of bis(cyclooctatetraene)iron [Fe[(COT).sub.2]] ensue. The stoichiometric reaction leads to the isolation of a previousty unknown mixed-valent species, featuring distinct and directly bonded Fe(O) and Fe(I) centers. In the catalytic process, three iron atoms are fused to afford the tri-iron duster [Fe.sub.3][(COT).sub.3], which is a hydrocarbon analog of Dewar's classic [Fe.sub.3][(CO).sub.12] complex. The key step in both of these processes is proposed to involve the NHC's ability to induce metal--metal bond formation. These NHC-mediated reactions provide a foundation on which to develop future organometallic transformations that are catalyzed by organic species. 10.1126/science.1178919

An investigation of various solvent-free matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) sample preparation methods for the characterization of organometallic and coordination compounds is described. Such methods are desirable for insoluble materials, compounds that are only soluble in disadvantageous solvents, or complexes that dissociate in solution, all of which present a major 'difficulty' to most mass spectrometry techniques. First-row transition metal acetylacetonate complexes, which have been characterized previously by solution preparation MALDI-TOFMS, were used to evaluate the various solvent-free procedures. These procedures comprise two distinct steps: the first being the efficient 'solids mixing' (the mixing of sample and matrix), and the second being the effective transfer of the sample/matrix mixture to the MALDI target plate. This investigation shows that vortex mixing is the most efficient first step and that smearing using a microspatula is the most effective second step. In addition, the second step is shown to be much more critical than the first step in obtaining high-quality data. Case studies of truly insoluble materials highlight the importance of these techniques for the wider chemistry community.

The activation energies are measured for phosphine dissociation and ring-closing metathesis for cationized Grubbs first and second-generation catalysts in the gas phase by deconvolution of the energy-resolved collision-induced dissociation cross-sections of electrosprayed ruthenium carbene complexes. The absolute binding energies have agreed well with the latest density functional theory calculations by using a density functional specifically suited for organometallic thermochemistry.

A peptide-based metal-organic framework (MOF), a metal peptide framework (MPF), constructed from an oligovaline peptide family is described. The MPFs are stable and have some internal porosity, which has made them a promising prototype for the further development of MPFs.

A stoichiometric system in which changes of a metallaborane is mediated by insertion of two alkynes into an irdaborane framework through a disposable molybdenum chaperone carbonyl fragment is presented. The complete procedure, 1+2alkyne= 8+B [H.sub.3]+2[H.sub.2], promoted by (arene)(Mo)[(CO).sub.3], serves as an example of a transition-metal-facilitated process analogous to metal-facilitated organic transformations seen in organometallic chemistry.

The construction of complex architectures from simple building blocks is feasible using subcomponent self-assembly by forming covalent bonds around metal templates. Several rearrangement reactions involving substitution at both intraligand and metal-ligand bonds are possible as both covalent and coordinative bonds are formed reversibly, as also parallel preparation of structures from nonorthogonal combinations of subcomponents.

A theoretical study suggests that a two-layer ONIOM quantum mechanics (QM)-molecular mechanics (MM) optimization of P[R.sub.3] ligands, followed by molecular electrostatic potential (MESP) analysis of the QM layer is a simple and effective method for evaluating the steric effect of the ligands. The proposed method is effective in studying the steric effect of bulky ligands and their various conformations in real time for practical purposes, and also organometallic complexes like metathesis catalysts.

Reaction of [Me.sub.3]SiONa with [Re[(CO).sub.5]Cl] affords the new complex Na[[Re.sub.2][(CO).sub.6] [([micro]-Osi[Me.sub.3]).sub.3]], which could be generated via formation of [Re[(CO).sub.5]Osi[Me.sub.3]] followed by immediate reaction with [Me.sub.3]Si[O.sup.-]. Substitution of some CO ligands by phosphines significantly decreases the electrophilicity of the Re(I) center, and therefore hinders further attack by [Me.sub.3]Si[O.sup.-]. Thus, fac-[Re[(CO).sub.3]([Ph.sub.2]PC[H.sub.2]C[H.sub.2] P[Ph.sub.2])OTf] (OTf is the triflate anion) reacts with [Me.sub.3]SiONa to give fac-[Re[(CO).sub.3]([Ph.sub.2] PC[H.sub.2]C[H.sub.2]P[Ph.sub.2])Osi[Me.sub.3]], a molecular model of silica anchored [Re[(CO).sub.5]OSi [equivalent to]) However, substitution of only one CO by triphenylphosphine is not enough to avoid the formation of [[[Re.sub.2][(CO).sub.6] [([micro]-Osi[Me.sub.3]).sub.3]].sup.-]. While fac-[Re[(CO).sub.3]([Ph.sub.2]PC[H.sub.2]C[H.sub.2] P[Ph.sub.2])Osi[Me.sub.3]] is stable towards hydrolysis, [[Re.sub.2][(CO).sub.6] [([micro]-OSi[Me.sub.3]).sub.3].sup.-] is readily hydrolyzed to [[[Re.sub.2][(CO).sub.6]([micro]-OH) ([micro]-OSi[Me.sub.3]).sub.2]].sup.-] , a molecular model of silica anchored [[[Re.sub.2][(CO).sub.6]([micro]-OH) [([micro]-OSi [equivalent to].sub.2].sup.-], whose structure has been determined by single crystal X-ray diffraction. Key words: surface organometallic chemistry, rhenium, silica, silanolate, molecular model. La reaction de [Me.sub.3]SiONa avec [Re[(CO).sub.5]Cl] fournit le nouveau complexe Na[[Re.sub.2][(CO).sub.6][([micro]-OSi [Me.sub.3]).sub.3]], probablement genere via la formation de [Re[(CO).sub.5]OSi[Me.sub.3]] suivie par une reaction immediate avec [Me.sub.3]Si[O.sup.-]. La substitution de quelques CO par des phosphines diminue fortement l'electrophilicite du centre Re(I) et, par consequent, empeche toute attaque ulterieure par [Me.sub.3]Si[O.sup.-]. Ainsi, fac-[Re[(CO).sub.3]([Ph.sub.2]PC[H.sub.2]C[H.sub.2] P[Ph.sub.2])OTf] (OTf est l'anion triflate) reagit avec [Me.sub.3]SiONa pour donner fac-[Re[(CO).sub.3] ([Ph.sub.2]PC[H.sub.2]C[H.sub.2]P[Ph.sub.2])OSi[Me.sub.3]], modele moleculaire de l'espece ancree a la silice [Re[(CO).sub.5]OSi [equivalent to]]. Cependant la substitution d'un seul CO par la triphenylphosphine ne suffit pas a empecher la formation de [[[Re.sub.2][(CO).sub.6]([micro]-OSi[Me.sub.3]).sub.3]].sup.-]. Alors que fac-[[Re[(CO).sub.3]([Ph.sub.2]P[CH.sub.2][CH.sub.2] P[Ph.sub.2])OSi][Me.sub.3]] est stable en presence d'eau, [[Re.sub.2]](CO).sub.6] ([micro]-OSi[Me.sub.3]).sub.3].sup.-] s'hydrolyse rapidement pour donner [[[Re.sub.2][(CO).sub.6]([micro]-OH) ([micro]-OSi[Me.sub.3]).sub.2]].sup.-], modele moleculaire de l'espece ancree a la silice [[Re.sub.2][(CO).sub.6]([micro]-OH)([micro]-OSi [equivalent to])2].sup.-], dont la structure a ete determinee par diffraction des rayons X. Mots cles : chimie organometallique de surface, rhenium, silice, silanolate, modele moleculaire.

A photo and thermally stable bis(amidate)-dibenzyl complex of Hf ([[sup.DMP][(NO).sup.Ph].sub.2]Hf[(C[H.sub.2]Ph).sub.2](THF) (2a) was formed as a monosolvated THF adduct in near quantitative yield from [Hf[(C[H.sub.2]Ph).sub.4] and N-2,6-dimethylphenyl(phenyl)amide (1). Isomerization between the THF-bound product and the THF-free product can be observed visually by the conversion from a red-orange product at low temperatures to a pale yellow product at high temperatures. Solid-state crystallographic characterization of the orange product confirmed its constitution as a monosolvated species. Kinetic parameters for the exchange of the THF moiety were determined from variable-temperature NMR experiments. The product of the hydrolysis of the Hf dibenzyl species by water was characterized by X-ray crystallography, and was found to be a rare tetrametallic Hf oxo cluster species (3). Key words: hafnium, protonolysis, amidate, coordination chemistry, organometallic chemistry, exchange processes. Un complexe de bis(amidate)-dibenzyle de Hf ([[[sup.DMP][(NO).sup.Ph]].sub.2]Hf[(C[H.sub.2]Ph).sub.2](THF) (2a) qui est stable a la lumiere et a la chaleur a ete forme comme adduit monosolvate de THF avec un rendement presque quantitatif de Hf[(C[H.sub.2]Ph).sub.4] et N-2, 6-dimethylphenyl(phenyl)amide (1). L'isomerisation entre le produit avec THF et le produit sans THF peut etre observee visuellement par la conversion d'un produit rouge-orange aux temperatures basses en un produit jaune pYle aux temperatures elevees. La caracterisation cristallographique du produit orange a l'etat solide a confirme sa constitution comme l'espece monosolvate. Des parametres cinetiques pour l'echange du THF ont ete determines a partir d'experiences de RMN a la temperature variable. Le produit d'hydrolyse de l'espece dibenzyle de Hf par l'eau a ete caracterise par cristallographie de rayons X et c'est une espece rare d'agregat oxotetrametallique de Hf (3). Mots cles : hafnium, protonolyse, amidate, la chimie de coordination, la chimie organometallique, processus d'echange.

An investigation is described regarding the approaches to the synthesis of the bis-indolyquinones focused on the controlled, sequential coupling of two indoles to a quinone core using organometallic methods. A report on the synthesis of a simple, symmetrical member of the class, demethylasterriquinone B4 is presented.

The present system describes unique examples of organogelators as well as thermotropic phenanthroline-based metallomesogen. The use of a potential hydrogen-bound director allows for the production of mesomorphic materials with both ligands and complexes.

A study is conducted to examine the behavior at the air-liquid interface of a series of metal(II) metallo-organic polymers of 4-octaecyl-1, 2,4-triazole. Interactions between those amphiphilic compounds and metal ions in the suphase result in the formation of stable monolayers and well-defined Langmuir-Blodgett films incorporating oligomeric metal(II)/triazole units.

Trialkylsilyltrialkylstannes (R3Si-SnR'3) add to 1,6-diynes in the presence of Pd(0) and trispentaflurophenylphosphine to give 1,2-dialkylidenecyclopentanes with terminal silicon and tin substituents. The (ZZ)-geometry of these s-cis-1,3-dienes, resulting from the organometallic reaction mechanism involved, forces the silicon and tin groups to be nonplanar, thus making the molecules axially chiral.

Nanoparticles of nickel have been obtained in solution through reaction of an organometallic precursor, Ni(COD)(sub 2) (COD=cycloocta-1, 5-diene), with dihydrogen, in the presence of various stabilizing agents. This stabilizing agent was selected for the production of nickel anorods, and the influence of ligands on the effective anisotropy is discussed.

The procedure for calculating homolytic dissociation rate constants for modeling organometallic vapor-phase epitaxy (OMVPE) of III-V compounds of all pressure regimes is reported. The comparison of predicted reaction rate constants with experimentally determined values show that the predicted reaction rate constants for In(CH(sub 3)(sub 3), Ga(CH(sub 3)(sub 3), AL(CH(sub 3)(sub 3) and low pressure NH(sub 3) are within 8 times the experimental values.

Research has been conducted on the steric effect on oranometallic chemistry. The effect of bulky alkyl groups on distortions in carbon monoxide complexes has been analyzed in investigating the possibility that carbon monoxide could bend or tilt in the system and the results are reported.

Design, synthesis, and study of a synthetic barrel-stave supramolecule with p-octiphenyl 'staves,' [beta]-sheet 'hoops,' and hydrophobic exterior as well as internal carboxylate clusters are reported. Ion transport experiments indicate the formation of transmembrane pores at 5 < pH < 7 with nanomolar activity. Blockage of dye efflux from spherical bilayers by external Mg[(OAc).sub.2] and internal 8-aminonaphthalene-1,3,6-trisulfonate is suggestive for weakly cooperative (n = 1.16) formation of aspartate-[Mg.sup.2+]-8-aminonaphthalene-1,3,6-trisulfonate complexes within the barrel-stave supramolecule ([K.sub.D] = 2.9 mM). Corroborative evidence from structural studies by circular dichroism spectroscopy is provided and discussed with emphasis of the importance of internal charge repulsion for pore formation and future applications toward binding and catalysis within supramolecular synthetic pores.

Manipulation of molecular crystals formed from self-organization is one of the important methods to develop the new molecular functional materials. In particular, we look upon mutual cohesive interactions of hydrogen bonding and metal coordination as one useful tool to construct the preprogramming superstructures. In this study, five controlled superstructures of a one-dimensional linear chain--a zigzag ribbon, right-handed and left-handed helices, and a two-dimensional honeycomb sheet--are newly created by using the neutral metal complexes with some 2,2'-biimidazolate mono-anions.

The basic structures for linking squares into polyhedra and networks (reticulation) are enumerated, and corresponding examples are described in which crystals were synthesized by linking paddle wheel (square) units into metal-organic frameworks (MOFs)--named MOF-102 to MOF-112.

The authors discuss the publications on transition metal- nitric oxide complex chemistry. The topics of interest include the effect of electron-withdrawing nitric oxide ligands on nitrosyl complexes' physical and chemical properties.

The author reviews some developments in the transition metal organometallic chemistry emphasising the areas to which the author has contributed himself. The topics of interest include fluxional organometallics, fluxional metal carbonyls and the agostic hydrogen atoms.

Research discusses the synthesis of organocobalt derivatives of tetracationic water-soluble porphyrins via a new reductive alkylation using sodium borohydrate as the reducing agent. Further, the binding interactions of the new cations with DNA and synthetic DNA polymers along with their photochemical behavior are presented.

Results demonstrate that catecholates and semiquinones can be synthesized from anthragallol, purpurin, and quinalizarin. Properties of ruthenium complexes of the polyhydroxy-9,10-anthracenediones purpurin, anthragallol, and quinalizarin are discussed.

Research has been conducted on the acyclic allylic alcohols of general structure. The use of the Sharpless kinetic resolution in resolving these alcohols and the results of the organocopper reagents reaction with the substrates derived from allylic alcohols are described.

Research demonstrates synthesis of four octanuclear organometallic squares by self-assembly between ligand complexes. Structural and elemental analyses reveal that the squares incorporate terpyridyl metal complexes as bridging ligands. All four heterometallic complexes exhibit strong visible absorption characteristic of iron, rubidium, or osmium metals.

Results demonstrate that magnesium ate complex facilitates the facile-halogen-magnesium exchange in aryl- and alkenyl- halides at low temperatures. Data indicate that the reaction can be used for preparing organomagnesium reagents and fine-tuned by selecting proper ligands on magnesium.

Research is presented concerning the photophysical and synthesis investigation of a family of cyclometalated iridium(III) complexes. The ligands within the cyclometalated complexes are discussed.

Reaction of S[O.sub.2] with trans-k(CO)(CI)[(TPPTS).sub.2] in water mirrors the nature of S[O.sub.2] dissolved in water. At low pH (pH = 1) where S[O.sub.2] exists as the hydrated species S[O.sub.2]*[H.sub.2]O, only Ir(CO)(C1)(S[O.sub.2])[(TPPTS).sub.2] forms. At higher pH (pH = 6) where HS[O.sup.-.sub.3] dominates, no S[O.sub.2] complex is observed and a hydride, Ir(CO)(Cl)(H)(OH)[(TPPTS).sub.2], is the primary product. A mixture of S[O.sub.2] and [O.sub.2] does not lead to an iridium sulfate or show any evidence of the dioxygen adduct upon reaction in water with trans-Ir(CO)(Cl)[(TPPTS).sub.2], in contrast to the analogous reaction in organic solvents. In water, only the S[O.sub.2] complex, Ir(CO)(Cl)(S[O.sub.2])[(TPPTS).sub.2], is observed prior to decomposition. The contrasts to the P[Ph.sub.3] analogues in organic solvents provide further insight to water as a solvent for organometallic complexes. Key words: iridium(I), sulfur dioxide, water soluble, TPPTS.

Degenerate alkylidene proton exchange is observed in the novel reactivity of ruthenium alkylidenes in protic solvents.

Organometallic rings are investigated in terms of ring-opening polymerization behaviour.

The organically templated hydrogen phosphites are built up from HPO(sub)3 pseudopyramids and ZnO(sub)3N tetrahedra, in which the Zn-N bond represents a direct link between zinc and the 2-cyanoguanidine template. The polymorphs of 2-cyanoguanidine zinc hydrogen phosphite are synthesized from infinite layers of HPO(sub)3 and ZnO(sub)3N groups into 4- and 8-rings.

The platinum-bound iodide in the organoplatinum(II) complex is not directly involved in the binding of sulfur dioxide or the metal-bound halide in the complex has any influence on the binding process. The dissociative exchange of sulfur dioxide fastly occurs at ambient temperatures, making it ideal for sensor response applications.

Research demonstrates that the alpha-diimine enhances the photostability of the coordination and organometallic compounds. Data indicate that at absolute temperature of 80, the photostability extends from four microseconds to one millisecond due to an inefficient decay to the sigma-bond-to-ligand charge transfer state.

Research examines uniqueness of the cycloaddition in platinum(IV) compounds in the context of understanding the reactivity of organonitrile complexes. Data indicate that the cycloaddition occurs under mild conditions in case of highly reactive platinum(IV) compounds whereas in platinum(II) complexes, the reaction requires an electron-acceptor substituent.

This review discusses a range of polymer-supported carbon-carbon bond-forming reactions employed in solid-phase peptide synthesis in terms of synthetic methodology, development of novel linkers, and technology application to the synthesis of a combinatorial library of compounds. The Diels-Alder reaction and the domino reaction are employed to obtain multiple carbon-carbon bonds.

Research discusses polyoxometalates containing transition metal ions such as tungstoarsenate complexes with respect to their structural and magnetic properties. They crystallize in the orthorhombic and monoclinic systems with divalent metals occupying a square pyramidal environment. Magnetic properties of the complexes exhibit two d(sup)1 magnetic centers with the two V(sup)iv being antiferromagnetically coupled.

Research investigating additions of lithium phenylacetylide to N-(-n-butyl)imine of cyclohexane carboxaldehyde is presented. It is concluded that considerable aging effects are found as a result of IR spectroscopic analyses.

Pt(O)/Pd(O) metallocryptates encapsulating Ti(I) were constructed using phosphineimine ligands.