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The total synthesis of the Chinese herbal medicine (-)-Bao Gong Teng A from the multipurpose enantiomeric scaffold is described. Bao Gong Teng A is synthesized by an organometallic chiron strategy in which single enantiomers of TpMo(CO)(sub 2)(eta(super 3)-pyridinyl) complexes are produced in quantity and then elaborated efficiently to generate, after demetalation, highly enantiopure advanced synthetic intermediates possessing the tropane core.

Organometallic compounds offer broad scope for the design of therapeutic agents, but this avenue has yet to be widely explored. A key concept in the design of anticancer complexes is optimization of chemical reactivity to allow facile attack on the target site (e.g., DNA) yet avoid attack on other sites associated with unwanted side effects. Here, we consider how this result can be achieved for monofunctional 'piano-stool' ruthenium(II) arene complexes of the type [[([[eta].sup.6]-arene)Ru(ethylenediamine)(X)].sup.n+]. A potentially important activation mechanism for reactions with biomolecules is hydrolysis. Density functional calculations suggested that aquation (substitution of X by [H.sub.2]O) occurs by means of a concerted ligand interchange mechanism. We studied the kinetics and equilibria for hydrolysis of 21 complexes, containing, as X, halides and pseudohalides, pyridine (py) derivatives, and a thiolate, together with benzene (bz) or a substituted bz as arene, using UV-visible spectroscopy, HPLC, and electrospray MS. The x-ray structures of six complexes are reported. In general, complexes that hydrolyze either rapidly (e.g., X = halide [arene = hexamethylbenzene (hmb)]) or moderately slowly [e.g., X = azide, dichloropyridine (arene = hmb)] are active toward A2780 human ovarian cancer cells, whereas complexes that do not aquate (e.g., X = py) are inactive. An intriguing exception is the X = thiophenolate complex, which undergoes little hydrolysis and appears to be activated by a different mechanism. The ability to tune the chemical reactivity of this class of organometallic ruthenium arene compounds should be useful in optimizing their design as anticancer agents. anticancer | bioorganometallic | hydrolysis | kinetics | ruthenium complexes

A large and diverse data set is presented which is used for testing existing density functionals and developing new ones. The most highly recommended functionals for accurate predictions of energetics and bond lengths of inorganometallic and organometallic compounds are G96LYP, followed closely by MPWLYP1M, XLYP, BLYP, and MOHLYP.

The physical properties and structures of a series of six complexes of the type (NiN2S2)W(CO)4 are used to establish electronic and steric parameters for square planar NiN2S2 complexes as bidentate, S-donor ligands. It is found that there is little difference in donor abilities of the five neutral ligands, while the dianionic ligand transfers more electron density onto the W(CO)4 moiety, and the spatial orientations of the ligands remain fixed with respect to the W(CO)4 moiety.

A series of metallocarboranes were produced by reacting [NEt(sub 4)](sub 2)[Re(CO)(sub 3)Br(sub 3)] or [ReCO)(sub 3)(OH(sub 2))(sub 3)]Br with corresponding carbonates in preaence of aqueous solutions of either alkaline metal or tetraalkylammonium fluoride salts. In the course of the reactions it was discovered that Re metallocarvoranes could be directly prepared from the respective closo-clusters under similar reaction conditions used with nido-carboranes.

The synthesis and spectroscopic characterization of 2-oxa-21-carbaporphyrin derivatives without appended pyrrole linked to the C(3) carbon including the inherently true O-confused 2-oxa-21-carbaporphyrin [(H)OCPH]H is described. The derivatives revealed a remarkable tendency to stabilize peculiar organometallic compounds and the ability of carbaporphyrinoids to coordinate metal ions and form metal-carbon bonds extends beyond the family of 2-aza-21-carbaporphyrins.

The application of the Ellman-Davis method is reported to the asymmetric synthesis of 2-piperazinylbenzylamines amines bearing alpha-substituent. The efficient synthesis and deprotection of the N-Boc-2-piperazinylbenzyl-tert-butanesulfinamides constitutes an attractive method for extensive structure-activity studies in the search for novel ligands of the human melanocortin 4 receptor.

The synthesis of 11(beta)-perfluorohexylestradiol is reported using a perfluoroorganometallic reagent for the introduction of the fluorous part. The key step of the synthesis involves the radical reduction of an 11(beta)-oxalate derivative.

An ab initio investigation of second-order nonlinear optical (NLO) properties and absorption electronic spectra of push-pull transition metal chromophores of the formula [M(CO)(sub 5)L] is reported. The investigation pointed out the opportunities and limitations of ab initio schemes when applied to rather simple organometallic chromophores, in the context of NLO and excited state properties.

The complete catalytic reaction course for the organolantanide-mediated intramolecular hydroamination/cyclization (IHC) of (4E,6)-heptadien-1-amine by a prototypical achiral Cp(sub 2)LaCH(TMS)2 procatalyst is critically scrutinized by employing a gradient-corrected DFT method. The condensed free-energy profile for the overall catalytic reaction, comprised of thermodynamic and kinetic aspects of individual elementary steps is presented.

The first solid-state (super 39)K NMR spectra of organometallic complexes cyclopentadienyl potassium (CpK) and pentamethylcyclopentadienyl potassium (Cp*K) is presented. A high S/N (super 39)K spectrum of broad central transition of Cp*K with a breadth of ca. 200 kHz is acquired with the help of piecewise quadrupolar Carr-Purcell Meiboom-Gill (QCPMG) NMR techniques.

A study describes the synthesis of organometallic derivatives of polyoxotungstates. Details of the two series of complexes [PW11O39{Ru(arene)(H2O)}](super 5-) and [{PW11O39{Ru(arene)}}2WO2](super 8-) that is obtained by reaction of [Ru(arene)Cl2]2 with [alpha-PW11O39](super 7-) in water are discussed.

Several nitro-substituted aryl and heteroaryl iodides undergo an iodine-magnesium exchange reaction when treated with PhMgCl leading to nitro-containing magnesium organometallics. These Grignard reagents display an excellent stability at temperatures below -40 degree Celsius, do not undergo electron-transfer reactions, and react as expected with various electrophiles.

The preparation of a 1,3-alternate calix[4]arene tetraphosphane ligand, 25,26,27,28-tetrakis{2-(diphenyliphosphino)-ethoxy}calix[4]arene is described. Two organometallic fragments inclusioned inside a 1,3-alternate calix[4]arene tetraphosphane are achieved by the reaction of 1,3-alternate calix[4]arene tetraphosphane ligand, 25,26,27,28-tetrakis{2-(diphenyliphosphino)-ethoxy}calix[4]arene with [PtH(PPh3)2(thf)](super +).

One new conjugated symmetric fulvene ligand and two new unsymmetric fulvene ligands are synthesized and five new supracomplexes are obtained through self-assembly based on these three new fulvene ligands in a benzene/toulene mixed-solvent system. The results indicate that the coordination chemistry of new fulvene ligands is versatile.

A facile and simple method for the preparation of 3,4-dialkyl-3,4-dihydro-2H-1,3-benzoxazin-2-ones or naphthoxazin-2-ones in high yields from aminoalkylphenols and aminoalkylnaphthols is described. The reactions of the products obtained with organolithium and Grignard reagents were studied, and a method for the preparation of N-[1-2-hydroxyphenyl)alkyl]-N-alkylamides, which are of pharmaceutical interest, from benzoxazinones was developed. A possible reaction mechanism is also proposed. The relative configuration of chiral products was determined from conformational analysis of [sup.1]H NMR spectra. Key words: benzoxazinones, naphthoxazinones, organometallic reagents, amide preparation, aminoalkylphenols.

A range of Pt-diimine complexes possessing fluoroalkyl and hydrofluoroalkyl ligands were synthesized from the readily prepared [Pt(diimine)[Me.sub.2]] complexes and the appropriate iodofluoroalkane. For complexes with diimine ligands containing substituents in the 2, 6-positions of the aryl group, Pt(II) complexes were obtained due to in situ reductive elimination of MeI, while for complexes with diimine ligands of smaller steric demands (possessing substituents in the 3,5-positions or the 4-position), Pt(IV) complexes were obtained. Attempts to convert the Pt(IV) complexes to the desired Pt(II) species via reductive elimination of MeI, methane, or ethane resulted in either no reaction or degradation of the starting complex. Fluoroalkyl(methyl) platinum(II) complexes were then converted to the fluoroalkyliodoplatinum(II) complexes via addition of [I.sub.2] or by reaction with aq HI. Several complexes have been characterized crystallographically. Key words: fluoroalkyl, organometallic synthesis, structure, platinum.

A multigram synthesis of a protected version of the C29-C51 subunit and the methodology for the union of this intermediate with the C1-C28 fragment to achieve the natural product is reported. By this route a total of 0.25 grams of the marine natural product was prepared.

A study proves that anionic and neutral organometallic gold(III) complexes (with one or two organic radicals) are able to catalyze the addition of water and methanol to terminal alkynes with a catalytic activity similar to that reported for Na[AuCl4]. The addition reactions follow the Markovnikov rule, giving the corresponding ketones or diacetal products.

The addition of organometallic reagents to cyclic ketones bearing stannyl groups at an appropriate distance to the carbonyl group occurs with a high level of stereocontrol, giving alcohols resulting from attack of the nucleophile syn to the tin center. The degree of selectivity observed depends on the spatial distance between the carbonyl group and the tin center.

Optimal geometries, harmonic vibrational frequencies, and relative energies of different sets of metal complexes are calculated using the effective group potentials (EGP) method. All of the systems under consideration contain the cyclopentadienyl (Cp) ligand.

The electrochromic linear and nonlinear optical properties of alkynylbis(diphosphine)ruthenium complexes are examined. A combination of cyclic voltammetry, UV-vis-NIR spectroelectrochemistry, and time-dependent density functional theory is used for this purpose.

The recognition of nucleic acid derivatives by organometallic ruthenium(II) arene anticancer complexes is investigated. The findings revealed that the diamine NH2 groups, the hydrophobic arene, and the chloride leaving group have important roles in the novel mechanism of recognition of nucleic acids by Ru arene complexes, and will aid the design of more effective anticancer complexes, as well as new site-specific DNA reagents.

The concept of forming and stabilizing xenon-containing compounds in the way, demonstrated for both organoxenonium salts and rate gas containing hydrides, is discussed and a prediction is done of a novel class of rare gas compounds that may expand the scope of the field. The studies showed the presence of molecules such as H-Xe-C2-H, H-Xe-C6-H5 and H-Xe-O-C6-H5.

The study was conducted to report the synthesis and characterization of novel organometallic polyphenylene demdrimers containing 24 or 44 phenyl rings and one cyclobutadiene cobalt unit. The scanning pulse voltammetry in solution showed that the dendrimers were oxidized at potentials ranging from 0.8 to 0.83 V.

The study reports on the results of the threshold photoelectron photoion compound spectroscopy of the kinetics of manganocene ion. Manganocene is an important organometallic compound, which possesses pivotal magnetic properties necessary in catalytic reactions.

A study of organometallic- and organic-based materials, which exhibit the technologically important property of bulk magnetism, are designed and prepared. The results show that these molecule-based magnets differ from conventional magnets as they are fabricated by low-temperature organic chemistry methodologies, in contrast to high-temperature metallurgical methods typical of classical magnets.

Research gas-phase molecular association reactions of dimethylaluminum hydride have been studied with density functional theory (DFT) and ab initio MP2 methods to understand the dimer trimer equilibrium. In conclusion, on the basis of the current results, experimental observations of a complex DMAH dimer trimer equilibrium can be understood in terms of a series of the slow, bimolecular and relatively faster unimolecular reactions.

A series of 25 new organoantimony(V) cyanoximates are synthesized and studied using IR, visible and NMR spectroscopy and X-ray analysis. All the compounds were found to be monomeric both in solution and solid state.

A series of experiments are conducted which focus on the synthesis and catalytic activity of ruthenium-indenylidene complexes.

The synthesis and structural characterization of an ultramicroporous metal-organic framework based on 9,10-anthracenedicarboxylate is described. The complex exhibits very rare gas-adsorption selectivity of oxygen and hydrogen over nitrogen and carbon monoxide.

A family of metallaquartets generated through interaction of silver and modified adenine nucleobase is described. The complex is found to remain unaffected by subtle substitutions in the purine ring and counteranions.

A study report about a novel cascade supramolecular complex [Ag(L)](Sb[F.sub.6]).[C.sub.6][H.sub.6] with a reversible nanosized [{[([C.sub.6][H.sub.6]).sub.6][(Sb[F.sub.6].sub.12]}.sup.12-] H-bonded cage unit is presented. It demonstrates a new synthetic strategy to modular host framework that utilizes complicated metal-organic species as the template.

The quantitative photochemistry of Cp'Pt(CH3)(sub 3) (Cp' = eta(super 5)-C5H4CH3) in solution has been investigated. The photoefficiencies indicate that the qualitative photochemistry is 2 orders of magnitude higher than previously recognized.

The linear electrochromic behavior accompanied by third-order nonlinear optical elcetrochromic behavior, which is probe by a combination of femtosecond degenerate four-wave mixing (DFWM) and pump-probe, is investigated. The fast relaxation may be due to efficient energy transfer from the excited complex molecules and to solution interactions.

The threshold photoelectron photoion coincidence spectroscopy (TPEPICO) process is employed to analyze the mechanisms, energetics and isomerization taking place in the different metallocene ions. The bond energies exhibited by the system are shown to be highly dependent on the electronic structure of the ions.

Several modular studies are conducted to explain the synthesis and the coordination properties exhibited by the different zinc finger peptides. The half-life of the observed zinc exchange is shown to be highly dependent on the sequence of the zinc finger.

Several mechanistic studies are conducted to explain the mechanisms involved in the reactions taking place between the aromatic ketones with olefins. The rate of C-H/olefin coupling is shown to exhibit a complete dependence on the concentration of the ruthenium complex in the system.