Michael F. Farona

A one-step synthesis of bis(h5-cyclopentadienyl)zirconacyclopentadiene compounds

Abstract Bis( h 5 -cyclopentadienyl)zirconacyclopentadiene complexes were prepared by reduction of zirconocene dichloride in THF with magnesium in the presence of various alkynes. Hydrolysis leads to the corresponding ( E,E )-butadiene derivatives.

Polymer-anchored vanadyl catalysts for the oxidation of cyclohexene

Abstract Oxovanadium (IV) ion was incorporated onto several insoluble polymers containing ligand groups such as acetylacetonate, ethylenediamine, and pyridine. The general approach to the synthesis of the catalysts was to attach the ligand to a polymerizable monomer, carry out suspension polymerizations to form beads, and incorporate the metal ion, in that order. The catalysts thus formed were used for the epoxidation of cyclohexene with t -butyl hydroperoxide. The catalysts were generally more active than the homogeneous model, VO(acac) 2 , and the nitrogen-donor polymers could be recycled many times before gradual leaching of vanadyl ion caused a significant decrease in activity.

Olefin metathesis by rhenium carbonyl halide-alkylaluminum halide catalysts. Direct evidence for a coordinated carbene initiated process

The Re(CO)sX/RAlClZ system was found to be an effective, long-lived catalyst for the metathesis of terminal and internal olefins. Where X = C1 and R = C2H5, gas evolution studies and analysis of the minor components of the metathesis of 1,7-octadiene indicate that a coordinated propylidene is formed on Re by attack of ethyl on coordinated CO, followed by oxygen for hydrogen exchange. Investigation of the first-formed olefins in the metathesis of 1,7-0ctadiene and 4-octene indicates that propylidene is the initiating carbene in the reaction. The first-formed olefins in the metathesis of 1,7-octadiene were identified as 1-butene and 1,7-decadiene, while that of 4-octene was identified as 3-heptene. When CH3AIC12 was used as the cocatalyst, the first-formed olefins were identified as propylene and 2-hexene, for the metathesis of 1,7-octadiene and 4-octene, respectively. This work provides direct evidence that the process of olefin metathesis is both initiated and propagated by coordinated carbenes.

UNSYMMETRICAL TETRADENTATE COMPLEXES OF COPPER (II)

Abstract Four mixed tetradentate Cu(II) chelates were prepared by reacting a copper salt, acety acetone, and ethylene-diamine with salicylaldehyde, o-hydroxyacetophenone, o-hydroxypropiophenone, and o-hydroxybutyrophenone, respectively. The I.R., optical, and E.S.R. spectra were obtained and discussed with regard to the expected bonding changes and/or those predicted by a model molecular orbital calculation for mixed ligand complexes.

Olefin metathesis over a Re2O7/Al2O3 metathesis catalyst: Mechanism for initial metallacarbene formation

Abstract The mechanism for the initiation of olefin metathesis over the heterogeneous catalyst rhenium heptoxide on γ-alumina was studied, using a pulse catalytic microreactor. Of the currently proposed mechanisms for initial metal-carbene formation, only that which requires the reactant olefin to contain an allylic hydrogen, and proceeds by way of a π-allyl complex, predicts the first-formed olefins found in the product mixture. A critical test using isotopically labeled ethylene showed that ethylene did not self-initiate metathesis, but readily metathesized after the catalyst was activated with cis-2-pentene.

Reactions of arenetricarbonyl-group vib metals with halide and pseudohalide ion̈s

Abstract A variety of compounds of general formula (R 4 N) 3 [(CO) 3 MX 3 M(CO) 3 ](M = Cr, Mo, W; X = F, Cl, Br, I, OH, SCN, N 3 , OC 2 H 5 ) were prepared from AreneM(CO) 3 and tetraalkylammonium halide. A few compounds were prepared with two-member bridges with the formula (R 4 N) 2 [(CO) 3 MX 2 M(CO) 3 ]. These very rapid reactions of AreneM(CO) 3 with free halide and pseudohalide ions demonstrate the strong Lewis acid properties of AreneM(CO) 3 , and provide support for the contention that AreneM(CO) 3 serve as effective catalysts in Friedel-Crafts reactions by promoting ionic-type reactions.

Acrilamide and N,N-dimethylacrylamide complexes. II. N-protonation and N-bonding to some transition metal perchlorates and tetrafluouroborates☆

Abstract Simple molecular orbital calculations were carried out on acrylamide (AA) and N,N-dimethylacrylamide (DAA), the results indicating that molecules of lower energy are formed upon coordination through N rather than O. Protonation studies in FSO3H by nmr show that both AA and DAA are N-protonated, in agreement with the m.o. calculations. Complexes of some first row transition metal perchlorates and tetraflouroborates exhibit attachment through nitrogen for the AA but O-coordination for the DAA molecules. Steric factors are invoked to explain the different modes of bonding.

Acrylamide and N,N-dimethylacrylamide complexes. I. N-coordination to tin-(IV) halides☆

The complexes SnX4.2AA(X = Cl, Br; AA = acrylamide), SnCL4.2AA-d2, (AA-d2 = CH2CHCOND2) and SnX4.2DAA (DAA = N,N-dimethylacrylamide) have been prepared and characterized. Whereas the DAA complexes exibit the ⪡normal⪢ O-coordination, the AA complexes appear to the first examples of N-coordinated amides. The primary evidence for the different modes of bonding comes from mass spectral studies, with photoelectron, infrared, and nmr spectroscopy providing supporting evidence. Fragmentation patterns for SnCl4.2ADD and SnCl4.2AA show SnO+ and SnN+, SnNH+ and Sn NH2+ peaks, respectively. Apparently anomalous data from infrared and nmr studies are explained in terms of new resonance forms which contribute to the electronic structure through N-coordination. On the basis of low-frequency infrared studies, the AA complexes are assigned the cis, and the DAA complexes the trans, configurations. An evaluation of the utilization of the shifts upon the coordination of the infrared bands ν(NH2), ν(CO), δ(NH2) and ν(CN), as a means of determination of the mode of bonding of amides, is presented

Carbonylation of amines and diamines catalyzed by nickel carbonyl

Abstract The carbonylation of amines and diamines was carried out using nickel carbonyl as the catalyst. Reaction of butylamine, diethylamine, and diphenylamine with carbon monoxide all lead exclusively to the corresponding formamide derivative. Benzylamine reacts with carbon monoxide to yield urea and 1,2-diphenylethane. Diamines such as ethylenediamine 1,2-diaminopropane, and 1,3-propylenediamine react to yield a cyclic condensation product, a cyclic urea, and a carbamic acid.

Some metallabicyclo-octadienes and -nonadienes of dicyclopentadienyltitanium, - zirconium and -hafnium

Abstract Titanocene, zirconocene, and hafnocene dichlorides were reduced in the presence of terminally disubstituted 1,6-heptadiyne or 1,7-octadiyne to produce dicyclopentadienylmetallabicyclooctadienes and -nonadienes. The compounds were characterized by elemental analysis and 1 H and 13 C NMR spectrometry, and (C 5 H 5 ) 2 HfC 7 H 6 [Si(CH 3 ) 3 ] 2 was characterized by X-ray diffraction techniques. The compounds crystallized in the triclinic space group P 1 in a unit cell of dimensions a 10.214(2), b 12.213(2), c 10.051(3) A, α 79.53(2), β 105.25(2), γ 96.26(2)° and V 1187.2(5) A 3 . Refinement was done to a final agreement for 3950 reflections with F 0 2 3σ( F 0 2 ) of R ( F ) = 0.042