Yoshihiro Koide

1,3-diphenylamidine and methylaminopyridine compounds of gallium

Abstract Reaction of Ga ( t Bu ) 3 with the 1,3-diphenylamidine [PhN(H)C(H)NPh, H-dpam] yields monomeric ( t Bu ) 2 Ga ( dpam ) (1). The partial hydrolysis of 1 results in the isolation of ( t Bu ) 2 Ga (μ- dpam )(μ- OH ) Ga ( t Bu ) 2 (2), whose structure consists of a gallium dimer in which the amidine and hydroxide ligands bridge two Ga ( t Bu ) 2 moieties. Reaction of [Me2Ga(μ-Cl)]2 with H-dpam results in the complex [H2-dpam] [Me2GaCl2] (3). The solid state structure of 3 indicates the presence of a hydrogen bonded cation-anion complex, in which the core has a twisted eight-membered ring configuration. The versatility of amidines as both chelating and bridging ligands to gallium is discussed with respect to the predominance of bridging and chelating modes of coordination of carboxylates and triazenides, respectively. Reaction of 2-(methylamino)pyridine (H-map) with Ga ( t Bu ) 3 allows for the isolation of ( t Bu ) 2 Ga ( map ) (4). In contrast, reaction with [( t Bu ) 2 Ga (μ- Cl )] 2 and [Me2Ga(μ-Cl)]2 yields the Lewis acid base adducts, ( t Bu ) 2 GaCl ( H-map ) (5) and Me2GaCl(H-map) (6), respectively. Reaction of compound 6 with nPrNH2 does not result in the deprotonation of the H-map ligand, but ligand metathesis and the formation of ( t Bu ) 2 GaCl ( NH 2 n Pr ) (7). The structures of 2, 3, 6, and 7 have been determined by X-ray crystallography.

Fiber Reinforced Epoxy Resin Composite Materials Using Carboxylate-Alumoxanes as Cross-Linking Agents

Chemically functionalized alumina nanoparticles (carboxylate-alumoxanes) are used as the inorganic component of a new class of inorganic-organic hybrid materials. Lysine- or para- hydroxybenzoic acid-derivatized alumoxanes are readily prepared from the reaction of boehmite, [Al(O)(OH)] n , with the appropriate carboxylic acid. The peripheral organic hydroxides and amines of these carboxylate-alumoxanes either react directly with epoxide resins, such as the diglycidyl ether of bisphenol-A (DER 332), to form a hybrid material, or in the presence of an organic resin and hardener system to form a composite material. SEM and AFM show a uniform distribution of alumina nanoparticles within the resin matrix. The properties and cure times of the alumoxane hybrid and composite materials are distinct from both the pure resins and from a physical blend of the resins with traditional ceramic fillers. A significant increase in thermal stability and tensile strength is observed for both the hybrid and composite resin systems. In addition, both carbon fiber and carbon/Kevlar ® matting have been successfully incorporated into the hybrid resin systems resulting in further property improvements.

Molecular structure of PhOCH2CH(OH)CH2OPh

The molecular structure of PhOCH2CH(OH)CH2OPh has been determined. The C—O—C—C—C—O—C backbone adopts an anti-anti-anti-anti conformation. Inter-molecular O—H ··· O hydrogen-bonding results in dimeric units which stack into zig-zag tapes. Crystal data: orthorhombic, Pbca, a = 10.383(1), b = 8.0532(0), c = 31.295(3) Å, V = 2616.8(3) Å3, and Z = 8.

Molecular structure of [(tBu)2Al(μ-NHtBu)]2

AbstractThe crystal and molecular structure of [(tBu)2Al(μ-NHtBu)]2 has been determined. The unit cell contains two independent molecules with only slight variation in the orientation of thetert-butyl ligands. Crystal data: Triclinic,

ALUMOXANES AS COCATALYSTS IN THE PALLADIUM-CATALYZED COPOLYMERIZATION OF CARBON MONOXIDE AND ETHYELENE : GENESIS OF A STRUCTURE-ACTIVITY RELATIONSHIP

P\bar 1

Inorganic−Organic Hybrid and Composite Resin Materials Using Carboxylate-Alumoxanes as Functionalized Cross-Linking Agents

,a=9.0138(6),b=10.2944(8),c=15.791(1) Å, α=91.262(6), β=89.822(6), γ=106.141(6)°,V=1407.2(2) Å3,Z=2,R=0.039,Rw=0.041.

Methods and materials for fabrication of alumoxane polymers

The reaction of fe/f-butyl alumoxane ([(Bu)AIO]n, TBAO), with the enolizable ketones, 0=CEt2 and MeC(0)CH2CH2C(0)Me has been investigated by NMR spectroscopy and GC-mass spectrometry. TBAO promotes the aldol condensat ion of 0=CEt2 to yield the ß h y d r o x y ke tone , 0=C(Et)C(H)(Me)C(0H)Et2, which upon acid work-up is converted to 0=C(Et)C(Me)=CEt2 and Ε and Ζ 0=C(Et)C(H)(Me)C(Et)=C(H)Me. In contrast the reaction of TBAO with MeC(Q)CH2CH2C(Q)Me results in the intraand intermolecular aldol condensation to give OC(OH)(Me)CH2C(H)=C(Me) and 0=C(Me)C2H4C(0)CH2C(0H)(Me)C2H4C(0)Me. The relevance of these reactions to the alumoxane co-catalyzed polyketone, [CH2CH2C(0)]n, formation is discussed. Introduction We have recently demonstrated that tert-butyl alumoxane ([(Βυ)ΑΙΟ]η, TBAO) is a suitable co-catalysts for the palladium catalyzed co-polymerization of ethylene and carbon monoxide (Eq. 1). However, since the reaction of alkyl aluminum compounds with ketones has been exhaustively studied, and depending on the ketone and/or the aluminum alkyl group, is known to result in either alkylation, reduction, or enolization of the ketone, it is possible that the polyketone polymer will also be susceptible to attack from the TBAO. * Author to whom correspondence should be addressed at the Department of Chemistry, Rice University, Houston, TX 77251, USA.