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The synthesis and characterisation (IR, NMR, HR-MS, and X-ray crystallography) of six oxazoline Zn complexes, containing enolate ligands derived from a series of (Z)-1-R-2-(4',4'-dimethyl-2'-oxazolin-2'-yl)-efh-1-en-1-ols (R=[C.sub.6][H.sub.5], [C.sub.6][H.sub.4]-p-N[O.sub.2], [C.sub.6][H.sub.4]-p-O[CH.sub.3], [CF.sub.3], [CH.sub.3], or [CMe.sub.3]) is detailed. All derivatives are air-stable solids of formula Zn[([L.sup.n]).sub.2] and are formed in the presence of the title ligands and [NEt.sub.3]. Reasonable yields (53%-82%) are obtained with the exception of R= [CMe.sub.3] (9%); in this case, by-product formation and high solubility affected complex isolation. Crystallographic characterisation reveals that in all cases the ligands are bound in a [kappa].sup.2]-N, O-bonding motif. Little structural diversity is noted within the series; these complexes are further placed into structural context with related Zn materials containing oxazoline, phenolate, and (or) Schiff base ligands. Key words: oxazoline, coordination complexes, zinc, enolate, X-ray crystal structure, Introduction The naturally occurring Group 12 elements hold a unique position within coordination chemistry due to the overwhelming predominance of the +2 oxidation state. This is, of course, a result [...]

A method for the synthesis of substituted 1,2,4,5-oxadiazaboroles is described, in which hydroxylamines, nitriles, and diarylborinic acids engage in a three-component condensation reaction. The protocol provides access to a substitution pattern that is not readily available through other methods--namely, 2,3-disubstitution, with a tetracoordinate boron center. Structures of representative members of this class of heterocycles were determined by single crystal X-ray diffraction analysis. Key words: boron, condensation, heterocycles, nitriles, Introduction Boron-based heterocycles are of interest from several perspectives, (1) including fundamental studies of structure, bonding, reactivity, and photophysical properties, along with potential applications in material science, (2) catalysis, (3) [...]

The 2-adamantyl (2-Ad) group is a particularly challenging alkyl to install on a transition metal, with the only reported 2-Ad complexes of platinum being those of Pt(II). The question of whether 2-Ad complexes with platinum in the oxidation state +IV can be made and whether they are stable is answered here. The Pt(IV) compound trans-[(bpy)[PtMe.sub.2](2-Ad)I] (bpy = 2,2=-bipyridine) was synthesized via oxidative addition of iodomethane to [(COD)PtMe(2-Ad)] (COD = 1,5-cyclooctadiene) in the presence of bpy. Iodide abstraction with silver triflate (triflate anion, [OTf.sup.-] = [CF.sub.3][SO.sub.3.sup.-]) produced trans-[(bpy)[PtMe.sub.2](2-Ad)(OTf)]. Both complexes were unambiguously characterizedby1DNMR ([.sup.1]H,[.sup.13]C) spectroscopy and X-ray crystallography. Both show evidence for the large steric bulk of the 2-Ad group (through the conformation of the complex adopted) and also for its exceptionally pronounced transinfluence (very long bonds to iodide/triflate trans to adamantyl). Both of the new platinum(IV) adamantyl complexes were extremely stable, even to prolonged heating. Key words: platinum(IV), oxidative addition, adamantane, density functional calculations, trans influence. Le groupe 2-adamantyle (2-Ad) est un group alkyle particulierement difficile a lier a un metal de transition; les seuls exemples connus de complexes de 2-Ad avec le platine sont ceux de Pt(II). Nous abordons dans le present article la question a savoir si les complexes de 2-Ade avec le platine a l'etat d'oxydation +IV peuvent etre fabriques et s'ils sont stables. Nous avons synthetise le complexe de Pt(IV) trans-[(bpy)[PtMe.sub.2](2-Ad)I] (bpy = 2,2=-bipyridine) par addition oxydante de l'iodomethane au [(COD)PtMe(2-Ad)] (COD = 1,5-cyclooctadiene) en presence de bpy. L'abstraction de l'atome d'iode par le triflate d'argent (anion triflate, [OTf.sup.-] = [CF.sub.3][SO.sub.3.sup.-]) a produit le trans-[(bpy)[PtMe.sub.2](2-Ad)(OTf)]. Nous avons caracterise sans equivoque les deux complexes par spectroscopie RMN 1D ([.sup.1]H, [.sup.13]C) et radiocristallographie. Les deux methodes revelent un fort encombrement sterique du groupe 2-Ad (par la conformation qu'adopte le complexe) et egalement une influence trans exceptionnellement marquee (liaisons tres longues entre l'iode ou le triflate et le groupe adamantyle). Les deux nouveaux complexes d'adamantylplatine(IV) etaient extremement stables, meme lorsqu'ils etaient exposes a une chaleur prolongee. [Traduit par la Redaction] Mots-cles : platine(IV), addition oxydante, adamantane, calculs de la fonctionnelle de la densite, influence trans., Introduction The chemistry of platinum alkyls has been a testbed for new organometallic chemistry for over 110 years now. When Pope and Peachey synthesized trimethylplatinum(IV) iodide in 1909, it was [...]

(Z)-1,2-Dihaloalkenes are thermodynamically disfavoured of the two stereoisomers. This paper reports the synthesis of some (Z)-1,2-dichloroalkene analogues from mucochloric acid. A more versatile approach involved the chloroboration of terminal alkynes to yield corresponding (Z)-chloroboronic acid as a first step. Treatment of the organoboronic acid with potassium hydrogen difluoride followed by tetrabutylammonium trichloride gave (Z)-1,2-dichloroalkenes in moderate to good yields in a stereospecific manner. Key words: cis-dichloroalkene, chloroboration, chlorodeboronation, NOE, terminal alkyne. Dans les series de 1,2-dihalogenoalcenes, les isomeres (Z)- sont thermodynamiquement defavorises. Dans ce travail, on a realise la synthese de quelques analogues de (Z)-1,2-dichloroalcenes a partir de l'acide mucochlorique. Une approche encore plus versatile implique une premiere etape de chloroboration d'alcynes terminaux qui conduit a l'acide (Z)chloroboronique correspondant. Le traitement de l'acide organoboronique avec du difluorure de potassium et d'hydrogene, suivi d'une reaction avec du trichlorure de tetrabutylammonium fournit les (Z)-1,2-dichloroalcenes d'une maniere stereospecifique, avec des rendements allant de moderes a bons. Mots-cles : cis-dichloroalcene, chloroboration, chlorodeboronation, effet Overhauser nucleaire (EN), alcyne terminal. [Traduit par la Redaction], Introduction 1,2-Dihaloalkenes are useful precursors in organic synthesis, particularly in the carbon-carbon bond-forming reactions. (1) Of the two stereoisomers, (Z)-isomers have found applications in reactions such as the Bergman cyclization. [...]

Synthesis, structure, and NMR spectroscopic data for [(closo-C[B.sub.11] [H.sub.6][Br.sub.6])PtMe3] are reported. This neutral platinum(IV) complex contains the closo-C[B.sub.11][H.sub.6][Br.sub.6.sup.-] anion bonded to the trimethylplatinum(IV) cation via three boron-bound bromines. Closo-C[B.sub.11][H.sub.6][Br.sub.6.sup.-], which often acts as weakly coordinating or even non-coordinating anion, adopts here a role still very rare for this anion: it acts as a tripodal capping ligand enabling a pseudo-octahedral geometry at a [d.sup.6] metal center. Three bromines from the lower hemisphere of the hexahalogenated carboranate coordinate to Pt(IV), and distortions from ideal octahedral angles at Pt are marginal ( Key words: non-coordinating anion, platinum(IV), trimethyl, closo-carboranate, tripodal, trans-influence, NMR spectroscopy. On a realise la synthese et on a determine la structure et les donnees de spectroscopie RMN relative au [(closo-C[B.sub.11][H.sub.6][Br.sub.6])Pt[Me.sub.3]]. Ce complexe neutre de platine(IV) contient un anion closo-C[B.sub.11][H.sub.6][Br.sub.6.sup.-] lie a un cation trimethylplatine(IV) par le biais de trois atomes de bore lies a des atomes de brome. L'anion closo-C[B.sub.11][H.sub.6][Br.sub.6.sup.-] qui agit souvent comme un anion de coordination faible, qui est meme quelquefois non coordinant, adopte dans notre cas un role encore plus rare pour cet anion, a savoir celui de ligand tripode qui sert de cap et qui permet d'avoir une geometrie pseudo-tetraedrique au niveau [d.sup.6] du centre metallique. Les trois atomes de brome de la partie inferieure de l'hemisphere du carboranate hexahalogene se lient par coordination au Pt(IV) et les distorsions par rapport aux angles octaedriques ideaux au niveau du platine sont marginales ( Mots-cles: anion non coordinant, platine(IV), trimethyle, closo-carboranate, tripode, influence trans, spectroscopie RMN. Traduit par la Redaction], Introduction The development of noncoordinating (or very weakly coordinating) anions has led to tremendous progress in the field of highly Brinsted-acidic or Lewis-acidic species (1). Closo-carboranates (2) have proven excellent [...]

The photolytic and thermal reactivity of [1]- and [2]-metallocenophanes are analyzed. This has shown that either reversible or irreversible haptotropic rearrangements from [[eta].sup.5]- to [[eta].sup.1]-Cp are seen depending on the degree of strain present.

The isolation and characterization of a variety of phosphonium and carbonyl halochalcogenate salts is reported. The monodentate neutral donor ligands strongly support a two-electron redox reaction between the Lewis base and the chalcogen tetrahalide.

The studies of unexpected reaction of trichloro(N-silyl)phosphoranimine CI3P=NSiMe3 with tertiary P=NSiMe3 phosphines, which generates N-(phosphino)-phosphoranimines, R3P=N-PCI2 is reported. This has been used as a ligand precursor in synthesis of a series of transition-metal complexes and prepares novel lithium imidophosphate clusters and spirocycles.

Equilibrium constants ([K.sup.DM]) for reactions between acids and bases of the title compounds in C[D.sub.2][Cl.sub.2] (DM) have been determined by [sup.31]p and ¹H NMR spectroscopy at room temperature. [HP[Cy.sub.3]]B[Ph.sub.4] and [HP[Cy.sub.3]]B[F.sub.4], with p[K.sup.DM] assigned by literature convention to 9.7, have been used as the anchor compounds for the p[K.sup.DM] determinations. A continuous scale of p[K.sup.DM] values covering the range 9.7 to 5.7 is created with the acidic compounds [HP[R.sub.3]]B[Ph.sub.4]. Those acids with p[K.sup.DM] greater than 6 are stable, while those with more acidic cations HP[R.sub.3.sup.+] protonate B[Ph.sub.4.sup.-] to produce [R.sub.3]PB[Ph.sub.3] and benzene. The literature p[K.sup.THF] values reported for [HP[Bu.sub.2]Ph]B[Ph.sub.4], [HPMe[Ph.sub.2]]B[Ph.sub.4], and [HPEt[Ph.sub.2]]B[Ph.sub.4] are questionable because of this protonation reaction. NOE and PGSE ¹H NMR techniques are used to show that [HP[Cy.sub.2]Ph]B[Ph.sub.4] in DM exists as ion pairs and higher aggregates up to quadrupoles at the concentrations used in the acid-base studies. The new dihydrogen complexes [Ru([H.sub.2]) Cl[(P[Ph.sub.3]).sub.2](dach)]B[F.sub.4] (dach = (1R,2R)-(-)-diaminocyclohexane) and [Ru([H.sub.2])Cl{tme [P.sub.2][(NH).sub.2]}]B[F.sub.4] (tme[P.sub.2][(NH).sub.2] = [Ph.sub.2][C.sub.6][H.sub.4]C[H.sub.2]NHC[Me.sub.2]C[Me.sub.2] NHC[H.sub.2][C.sub.6][H.sub.4]P[Ph.sub.2]) were prepared by reaction of RuHCl[(P[Ph.sub.3]).sub.2](dach) and RuHCl{tme[P.sub.2][(NH).sub.2]} with HB[F.sub.4]. Their crystal structures are reported, and the p[K.sup.DM] values of their B[Ph.sub.4.sup.-] salts were determined to be 8.6 and 6.9, respectively. Key words: acidity, dihydrogen complex, hydride, phosphonium, dichloromethane. Operant a la temperature et dans le C[D.sub.2][Cl.sub.2] (DM) comme solvant et faisant appel a la spectroscopie RMN du ¹H et du ¹P, on a determine les constantes d'equilibre, [K.sup.DM], des reactions entres les acides et les bases des composes mentionnes dans le titre. La valeur de 9,7 attribuee par convention dans la litterature pour les composes [HP[Cy.sub.3]]B[Ph.sub.4] et [HP[Cy.sub.3]]B[F.sub.4] a ete utilise comme composes de reference pour les determinations des p[K.sup.DM]. On a cree une echelle continue de valeurs de p[K.sup.DM] s'etalant de 9,7, a 5,7 en faisant appel aux composes acides [HP[R.sub.3]]B[Ph.sub.4]. Ces acides dont les valeurs de p[K.sup.DM] sont superieures a 6 sont stables alors que ceux des cations plus acides HP[R.sub.3.sup.+] se protonent au B[Ph.sub.4.sup.-] pour conduire a la formation de [R.sub.3]PB[Ph.sub.3] et de benzene. Les valeurs de p[K.sup.THF] rapportees dans la litterature pour les [HP[Bu.sub.2]Ph]B[Ph.sub.4], [HPMe[Ph.sub.2]]B[Ph.sub.4] et [HPEt[Ph.sub.2]]B[Ph.sub.4] ne sont pas fiables en raison de cette reaction de protonation. On a utilise les techniques d'effet Overhauser nucleaire et d'echo de spin a champ pulse PGSE en RMN du ¹H pour montrer que dans le DM, aux concentrations utilisees pour les Etudes acide-base, le [HP[Cy.sub.2]Ph]B[Ph.sub.4] existe sous la forme de paire d'ions et d'agregats plus importants allant jusqu'a des quadrupoles. La reaction du RuHCl[(P[Ph.sub.3]).sub.2](dach) et RuHCl{tme[P.sub.2][(NH).sub.2]} avec du HB[F.sub.4] a permid de preparer les deux nouveaux complexes de dihydrogene suivants [Ru([H.sub.2])Cl[(P[Ph.sub.3]).sub.2] (dach)]B[F.sub.4] (dach = (1R,2R)-(-)-diaminocyclohexane) et [Ru([H.sub.2])Cl{tme[P.sub.2][(NH).sub.2]}]B[F.sub.4] (tme[P.sub.2][(NH).sub.2] = P[Ph.sub.2][C.sub.6][H.sub.4] C[H.sub.2]NHC[Me.sub.2] C[Me.sub.2]NHC[H.sub.2][C.sub.6] [H.sub.4]P[Ph.sub.2]) dont on a determine les structures cristallines et les valeurs de p[K.sup.DM] de leurs sels B[Ph.sub.4.sup.-] qui s'etablissent respectivement a 8,6 et 6,9. Mots cles : acidite, complexe de dihydrogene, hydrure, phosphonium, dichloromethane. [Traduit par la Redaction], Introduction The quantitative study of the acidity of transition metal hydride and dihydrogen complexes serves to better the understanding of the reactions of these species in catalytic reactions, including those [...]

The borazine derivative is an outcome of the catalytic dehydrocoupling of NH3.BH3, MeNH2.BH3, and PhNH2.BH3 and the same is discussed. The TEM evaluation of the components of the reaction results in the catalyzed dehydrocoupling of Me2NH.BH3 along with Hg venomous test indicating a heterogenous catalytic method consisting of Rh(O) colloids.

The mechanistic details of the hydrogenation of ketones catalyzed by trans-dihydrido(diamine)ruthenium(II) complexes are examined. It is found that there is a heterolytic splitting of dihydrogen across the polar ruthenium-nitrogen bond.

The reaction of [Ph.sub.2]P(O)(Osi[Me.sub.3]) with [([[eta].sup.5] -[C.sub.5][H.sub.5])Ti[Cl.sup.3]] or [([[eta].sup.5]-[C.sub.5][Me.sub.5])Ta[Cl.sub.4]] in dichloromethane yields the complexes [[{([[eta].sup.5]-[C.sub.5][H.sub.5])Ti[Cl.sub.2] ([mu]-[Ph.sub.2]P[O.sub.2])}.sub.2]] (1) or [[{([[eta].sup.5]-[C.sub.5][Me.sub.5])Ta[Cl.sub.3] ([mu]-[Ph.sub.2]P[O.sub.2])}.sub.2]] (2), respectively. Structural analysis of 1 and 2 by single-crystal X-ray diffraction revealed the presence of eight-membered metallacycles consisting of bridging-bidentate diphenylphosphinate groups between two metal centers. Key words: inorganic rings, phosphinate complexes, tantalum, titanium.

The novel zirconatetraferrocenylcyclotrisiloxane [Cp.sub.2]Zr[(OSi[Fc.sub.2]).sub.2]O (6), dizirconatetraferrocenylcyclotetrasiloxane [[Cp.sub.2]Zr[(OSi[Fc.sub.2])O].sub.2] (7), boratetraferrocenylcyclotrisiloxane ([C.sub.6][H.sub.5])B[(OSi[Fc.sub.2]).sub.2]O (8), and diboratetraferrocenylcyclotetrasiloxane [[([C.sub.6][H.sub.5])B(OSi[Fc.sub.2])O].sub.2] (9) with ferrocenyl (Fe = Fe([eta]-[C.sub.5][H.sub.4])([eta]-[C.sub.5][H.sub.5])) substituents at silicon have been prepared from the reactions of [Cp.sub.2]Zr[(N[Me.sub.2]).sub.2] and PhB[Cl.sub.2] with diferrocenylsilanediol [Fc.sub.2]Si[(OH)sub.2](3) and tetraferrocenyldisiloxanediol [[[Fc.sub.2]SiOH].sub.2]O (5). The compounds were characterized by mass spectrometry, elemental analysis, UV-vis, IR, Raman, and multinuclear NMR spectroscopy, as well as single crystal X-ray diffraction. Thermogravimetric analysis and differential scanning calorimetry investigation of 6-9 showed that the cycles decompose before they can undergo any thermal ring-opening polymerization. In addition, no polymerization was detected in the presence of either KOSi[Me.sub.3] or HOTf. The bulky ferrocenyl substituents on the Si atoms are likely to be at least partially responsible for the inability of these heterocycles to undergo ring-opening polymerization. Key words: heterocyclosiloxanes, ferrocenyl.

Studies are conducted to devise methodologies as well as mechanisms for ring-opening polymerization (ROP) of strained [1]ferrocenophanes. It was found that the spontaneous ROP of tin-bridged [1]ferrocenophanes could be because of the presence of spurious trace quantities of Lewis basic or acidic impurities.

Research has been conducted on the ion pairs with the potassium-hydride and protonic-hydridic bonds. The structure and reactivity of these bonds have been investigated as a function of the phosphine ligand and the details are presented.

Research discusses the catalytic chemistry pertaining to dehydrocoupling of the sterically encumbered phosphine-borane adduct tBu(sub)2PH.BH(sub)3. Results reveal the involvement of rhodium complexes in the catalytic formation of phosphorous-boron bonds.

The hexahydridobis(phosphine)rhenate anions, [[Re[H.sub.6] ([PR.sub.3]).sub.2]]- ([PR.sub.3] = P[Cy.sub.3], P-i-[Pr.sub.3], P[Ph.sub.3], P[Me.sub.3]) were generated by potassium hydride deprotonation of the neutral heptahydride conjugate acids (Re[H.sub.7] [([PR.sub.3]).sub.2]), isolated as their [K(18-crown-6)]+ and [K(1,10-diaza-18-crown-6)]+ salts, and characterized by NMR and IR spectroscopy and elemental analyses. Structures from single crystal X-ray diffraction were obtained for the [K(1,10-diaza-18-crown-6)]+ salts and these indicate the presence of short protonic--hydridic bonds involving the hydrides of the anions and the proton donor NH moieties of the cations. The structure of [K(1,10-diaza-18-crown-6)][Re[H.sub.6] [(P-i-[Pr.sub.3]).sub.2]] adopts a one-dimensional zigzag chain with alternating cations and anions connected and held together by inter-ion N-H ... [H.sub.x]-Re interactions (x = 1 or 2). Short distances between the NH protons of the cations and hydrides of the anion ranging from 1.6 to 1.9 [Angstrom] are estimated for this complex. A different kind of chain structure is observed for [K(1,10-diaza-18-crown-6)][Re [H.sub.6][(P[Me.sub.3]).sub.2]] in which the combined effects of inter-ion protonic--hydridic bonding (N-H ... [H.sub.x]-Re) and inter-ion electrostatic interactions (Re[H.sub.x]- ... K+ ... [H.sub.x]- Re), result in one-dimensional networks of alternating cations and anions, with the metals and hydrides occupying the interior and the organic moieties of the phosphine ligands and crown ether lining the exterior of cylindrical supramolecular assemblies. A combination of intra- and inter-ion protonic-hydridic and intra-ion-pair electrostatic interactions in [K(1,10-diaza-18-crown-6)] [Re[H.sub.6][(P [Ph.sub.3]).sub.2]] result in the formation of discrete two-dimensional {[K(1, 10-diaza-18-crown-6)][Re[H.sub.6] [(P[Ph.sub.3])2]}.sub.4] tetramers. The P[Cy.sub.3] salt is disordered but appears to consist of isolated 1:1 ion pairs containing strong intra-ion-pair NH ... HRe bonding. The solid-state IR spectra of the [K(1,10-diaza-18-crown-6)]+ salts show low-frequency shifts for the NH bands relative to [K(1,10-diaza-18-crown-6)][[BPh.sub.4]], and perturbed Re-H bands relative to those in the [K(18-crown-6)]+ salts. The magnitude of [DELTA]vNH is related to the basicity of the anion as indicated by the p[K.sup.THF.sub.[alpha]] of the conjugate acid form (Re[H.sub.7] [([PR.sub.3]).sub.2]), which increases as P[Ph.sub.3] < < P[Me.sub.3] < P-i-[Pr.sub.3] < P[Cy.sub.3]. Solution [sup.1]H NMR, NOE, and [T.sub.1] relaxation measurements of [K(1,10-diaza-18-crown-6)] [Re[H.sub.6] [(P[Ph.sub.3]).sub.2]] indicate that these interactions also persist in toluene solutions of this compound. Key words: rhenium, hydride, phosphine, hydrogen bonding, self-assembly.

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

Research has been conducted on the electron-deficient dicationic complexes. Results indicate that dihydrogen complex stability depends on the metal-H (sub)2 sigma interaction.

A general process for the production of 1,2-bridged calix[4]arene monocrowns and biscrowns in the 1,2-alternate conformation was developed. The different factors affecting the conformational result in the reaction of 1,2-functionalized calix[4]arenes with glycol ditosylates and (super t)BuOK in toluene were also examined. This procedure is being used to design new enlarged hydrophobic cavities, based on 1,2-alternate calix[4]arene substructures, which may be useful for the selective inclusion of organic guests.

Single-crystal x-ray methods were used to identify the crystal structures of several novel alkylammonium phosphates. Findings indicated that the phosphates are arranged by layers and are separated by interdigitated or bilayers of organic amines. It was also observed that the cyclopentylammonium monohydrogen phosphate forms spontaneously in non-aqueous tetraethylene glycol starting synthesis mixture. Moreover, large crystals were also formed by recrystallization of the phosphates.

The synthesis of first-row transition metal and lanthanide dialkylaminosquarates similar to lead(II) analogues prepared earlier proved to be unsuccessful owing to the hydrolysis of the amino groups on the ligands. The salt (Mn(H2O)6)(HC4O3NH2)2, wherein the metal remained uncomplexed to the ligand, was the only compound successfully prepared that contained an amino group. The transition metal and lanthanide ions apparently intervened in the hydrolysis.

Research was conducted to examine the effects of the addition of bromine to ketenes and bisketenes. The study of the kinetics and mechanism of ketene bromination is intended to demonstrate both electrophilic attack at C(sub a) and neighboring group participation by the second ketenyl group. Results demonstrate that the bromination of the ketene PhMe2SiCH=C=O resembles the second order in (Br2) bromination behavior of ordinary alkenes in halogenated hydrocarbon solvents.

Synthesis and characterization of trans-M(H)(SPh)(dppe)2 (M = Ru, OS) were undertaken. The compound was characterized by nuclear magnetic resonance, infrared and mass spectroscopy, elemental analyses and voltametry. The protonation reactions undergone by the compound and its derivatives are investigated. Protonation reaction yields thiol and dihydrogen complexes. X-ray crystal structure of trans-Ru(H)(SPh)(dppe)2 and trans-[Os(H)(O2)(dppe)2](O3SCF3) is presented.

Synthesis of the first sulfur- and selenium-bridged [1]ferrocenophanes showed that these species have tilt angles of 31 degrees and 26 degrees respectively. Evidence for the high degree of ring strain was further provided by nuclear magnetic resonance chemical shifts of the ipso-carbon atoms in the [1]chalcogenaferrocenophanes. Data indicate that ring-opening polymerization reactions are less efficient in the formation of poly(ferrocenyl chalcogenides). Detailed studies of physical properties will be made when higher molecular weight samples of become available.

A new group of rhenium(I) and rhenium(II) amine dinitrogen complexes have been produced. Chemical analysis using infrared and electrochemical techniques was used to determine the amine complex precursor elongated dihydrogen species fac-[Re(PPh3)(PF3)dienOTf]OTf. Evidence suggests that the hydrogen ligand shape is due to a weak-field and to aspects of electron-donation.

Three series of oligo(ferrocenylsilanes) were prepared and characterized with respect to their conformational, solid-state and electrochemical properties. The oligo(ferrocenylsilanes), which were synthesized via the anionic ring-opening oligomerization of the ferrocenophane Fe(eta-C5H4)2SiMe2, were of the type R-fc-(SiMe2-fc)(sub n-1)-R' where fc = Fe(eta-C5H4)2, R = R' when R' = H, and R = H when R' = SiMe3. Their synthesis, which proved the occurrence of oxidation at alternating iron sites, revealed the existence of an intervalence electron transfer absorption for partially oxidized oligo(ferrocenylsilanes).

A new chain of aluminophosphate labeled, UT-7, and a new layered material, UT-8, were synthesized in a mixed cyclic amine system. The UT-7 is a non-framework aluminophosphate with a one-dimensional chain structure that undergoes solid state transformation under thermal conditions to form a layered material. UT-8 is a layered aluminophosphate with a molecular formula of [Al3PO4O16]3-. The layered aluminophosphate is also composed of two intermellar cyclic ammonium species.

The rotational frequency of the H2 ligand in trans-(Os(H..H)X(L)2)+, where L = phenyl, X = Cl, Br and L = ethyl, X = Cl, is near the Larmor frequency. The complex is octahedral and has an elongated dihydrogen ligand in solid-state and solution. The distance between the hydrogen atoms, d(sub HH), is calculated from coupling constant, J(H,D). The T1(min) value gives the limits for d(sub HH). The acidic character of these complexes is a function of the nature of X ligand.

The reaction of Ir(H)2(eta-2Spy)(PPh3)2 (Spy = 2-SC5H4N) with HSpy.HBF4 generates (IrH(eta-1-SC5H4NH)(eta-2-SC5H4N)-(PPh3)2)(BF4). The resulting complex contains bifurcated hydrogen bonding interaction with Ir-H...H(N)...F-B atoms. Iridium atom is enclosed by cis-PPh3 group, a chelating 2-pyridinethiolate and a 2-pyridiniumthiolate ligand. NMR spectra reveal isotope shifts in the chemical shifts of hydride and one phosphorus atom. The complex on reaction with D2 gas undergo slow H/D reaction. The X-ray crystal structure of the complex is discussed.

The metathesis of chloride for 2,6-diisopropylbenzenethiolate or selenolate from iron(II) chloride in the presence of 1-methylimidazole generates Fe(E-2,6-i-Pr2C6H3)2(1-MeIm)2 (E = S, Se; 1-MeIm = 1-methylimidazole) complexes. The complexes are pale orange or pale yellow. Cyclic voltametry, NMR and single-crystal X-ray diffraction are used to characterize these complexes. The complexes are oxygen susceptible, exhibit irreversible oxidation behavior and have a magnetic moment of 4.6 micron(sub B). The complexes form distorted tetrahedral conformation.

The intermolecular NH...H(Ir)...HN interactions of IrH(2-thiazolidinethione)4(PCy3) (BF4)2 were examined in both the solution and crystalline states. The results showed a novel four-membering ring formed by the hydrogen bonds between the NH groups and a fluorine of BF(sub 4)(super -). Intramolecular NH...Ir interactions have also been observed in the complexes Ir(H)2(PCy3)2(L)2 (BF4) for L = 2-thiazolidinethione and 2-benzothiazolethione.

The synthesis of crystalline mesolamellar aluminophosphates (MLA) involves the templating by self-agglomerated organic aggregates in non-aqueous tetraethylene glycol, phosphoric acid and amphiphilic alkylamine. X-ray diffraction analysis of the structure of MLA reveals that the morphology and surface patterns depend upon two distinct decylammonium dihydrogen phosphate assemblies. The skeletal characteristics of MLA such as deficiency of long-range order and bowl-like characteristics are found to be similar to radiolarians and diatoms.

Active catalysts that stimulate the homo-Diels-Alder cycloaddition reaction of electron-deficient olefins of bicyclo [2.2.1] hepta-2,5-diene (norbornadiene, NBD) were created. The activity of these catalysts is affected by nickel complex and the additives. The cycloadditions are highly regio- and stereoselective where the endo/exo selectivity is affected by the dienophile substituents, the catalyst and the temperature. A different [2pi + 2pi] cycloaddition is observed for a highly reactive dienophile with 2-substituted NBDs.

X-ray crystallographic studies of (RuCl(dppe)2)PF6 (dppe = Ph2PCH2CH2PPh2), formed by a reaction between NaPF6 and cis-RuCl2(dppe)2, reveal that the complex has a distorted trigonal bipyramidal geometry with a Y-shaped equatorial plane. Reaction of this complex with dihydrogen produces exclusively trans-(Ru(H2)Cl(dppe)2)+. Analysis of the influence of chloride and hydride on H-H bonding and acidity of these complexes using electrochemical data and bond dissociation energies reveals that H-H bonding exerts significant influence on the acidity of the complexes and H-H distances in Cl complexes are larger due to the pi effects of the chloride.

Silylphosphoranimines react with WCl(6) to give halogenated tungsten (VI) phosphoraniminate complexes through a chlorisilane elimination step. Another reaction involving chloride ion abstraction leads to a species which contains the tungsten analogue of the cation (Cl(3)PNP Cl(3))(super +). X-ray diffraction technique is used for structural characterization of these complexes.

Siloxane-bridged (n)ferrocenophanes of various ring sizes were synthesized and characterized. These complexes were obtained from methylated siloxane-bridged (n)ferrocenophanes, which also produced cyclic siloxane oligomers and other products obtained from the cleavage of cyclopentadienyl carbon-silicon bond in the presence of acid or base initiators.

Cyclosiloxanes in which the a skeletal silicon atom has been replaced by boron have been synthesized and characterized to determine their polymerization behavior. It was found that the release of ring strain and the formation of cyclic and polymeric siloxanes and the stable ring (PhBO)3 are driving forces of the ring-expansion reactions of PhBO(Me2SiO)2 and PhBO(Ph2SiO)2. Meanwhile, the ring-ring equilibration process for (PhBO)(Me2SiO)3 is slower and less strained. Ring-ring transformation reactions also occur to a limited extent in (PhBO)2(Me2SiO)4 and (PhBO)2(Ph2SiO)4.

The reaction of a solution of FeCl2 in methanol, TIM, and acetic acid with NaCN and then with NaBPh4 gives trans-Fe(TIM)(CNBPh3)2, (TIM = 2,3,9,10tetramethyl-1,4,8,11-tetracyclotetradeca-1,3,8,10-tetraene). The complex has an octahedral geometry with equatorial-TIM-ligand and axial-CNBPh3 ligands. The reaction mechanism involves abstraction of a phenyl anion from BPh4-. The resulting BPh3 reacts with the biscyano-Fe complex, which is electron rich and acts as a lewis base. The sensitivity of organometallic compounds to acid poses a limitation to the process.

The introduction of ring strain in the dienophile, as with moderately strained bicycle[2.2.1]heptenes (norbornene), has enabled three-component Povarov reaction with in situ formed N-arylimines under Lewis acid catalyzed conditions (B[F.sub.3].O[Et.sub.2]). The preference for the formation of exo-exo diastereomic adducts is seen in most cases, but the formation of exo-endo adducts is observed for reactions of ortho- or meta-substituted anilines.

The interaction between oxabicyclo(3.2.1)octenes and phenyldimethylsilyl form of copper lithium cyanide promotes the silacupration of the former. Examinations reveal that the silylcuprate undergoes an exo side attack on the bicyclic compound, but no ring opening reaction occurs without the prior addition of organocuprates. The organocuprates release the strain by compressing the steric bonds of the molecules in the bicyclic system. The use of dry silica gel allows the oxygenation of the silylcuprate so that it can undergo ring opening reaction.

Irradiation of silicon-bridged [1]ferrocenophane in the presence of substitutionally labile Lewis bases such as 4,4'-dimethyl-2,2'-bipyridine ([Me.sub.2]bpy) was performed to initiate ring-opening polymerization and oligomerization via cleavage of an iron-cyclopentadienyl bond. The cyclic and differential pulse voltammetry showed the electrochemical behavior of each cyclic oligomer to depend on the odd or even number of ferrocene units.

A series of phosphine-stabilized phosphoranimine cations [[[R.sub.3]P.P[R.sub.2]-[double bond]NSi[Me.sub.3]].sup.+] are prepared and the reactivities are studied. The density functional theory studies have shown that the difference in the [super 1][J.sub.pp] couplings are related to the electronegativity of the R- substituents at the phosphoranimine phosphorous center rather than the strength of the donor-acceptor P-P bond.

The analysis of the model compound chemistry is used for providing new insights into the mechanism of the ambient temperature P[Cl.sub.5]-initiated living cationic chain growth polycondensation of the N-silylphosphosphoranimine [Cl.sub.3]P[double bond]NSi[Me.sub.3] to yield poly(dichlorophosphazene). The results have identified the major factors that have complicated the living P[Cl.sub.5]-initiated chain growth polycondensation of [Cl.sub.3]P[double bond]NSi[Me.sub.3] and have led to the loss of control over molecular weight.

The efficient synthesis of the new catalyst precursor is described, which compared to (R,R)-1,2-diaminocyclohexane has higher activity and selectivity. The studies have shown the first Fe catalyst for the asymmetric transfer hydrogenation of ketones that has useful activity and enantioselectivity in the production of valuable enantioenriched alcohols.