Arnold L. Rheingold

Reactions of alkylphosphorus, arsenic, and antimony hydrides and halides with dibenzylmercury. An improved procedure for cyclopolyarsines

Abstract Dibenzylmercury is a convenient and general reagant for the formation of homoatomic catenates from primary alkyl phosphines, arsines and stibines. From CH3PH2, CH3AsH2 and C2H5AsH2, the products are Hgo and the cyclopentamers, (CH3P)5, (CH3As)5 and (C2H5As)5, respectively. From CH3SbH2, the solid, polymeric product, (CH3Sb)x, is obtained. With (CH3)2AsH, both the condensation product, (CH3)2AsAs(CH3)2, and the substitution product, (CH3)2AsCH2C6H5, are obtained. With dibenzylmercury, CH3PCl2, CH3AsCl2, and CH3SbCl2 give only the monosubstitution product CH3E(Cl)CH2C6H5 (E = P, As or Sb) and HgCl2. With CH3AsI2, disubstitution occurs giving (in addition to HgI2) CH3As(CH2C6H5)2, and with (CH3)2AsI, (CH3)2AsCH2C6H5. In all cases the conversion of starting materials to the indicated products is very high.

(Halomethyl)arsenic compounds : II. Preparation and dynamic NMR spectra of pentakis(chloromethyl)cyclopentaarsine☆

Abstract Hypophosphorous acid reduction of chloromethylarsonic acid produces the novel cyclopolyarsine, pentakis(chloromethyl)cyclopentaarsine (PCCA). PCCA possesses a greater thermal and oxidative stability than other cyclopolyarsines previously studied. The dynamic PMR properties of PCCA are interpreted as a combination of a low-energy limited pseudorotational motion and a higher-energy As-atom inversional process. An alternative to ground-state d-orbital participation in the interpretation of the electronic spectra is offered.

Preparation of Primary Alkylantimony Compounds

Abstract In comparison with the lighter group-V elements, access to primary alkyl compounds of antimony [containing either RSb(III) or RSb(V)] is impeded by the low thermal stability of the hydrides, RSbH2, and the puzzling non-existence of alkylstibonic acids, RSbO(OH)2. Existing procedures for the preparation of RSbX2 (X = halogen) frequently yield products which are difficult to separate and often have limited general application. New synthesis procedures and improvements in earlier procedures are described

(Halomethyl)arsenic compounds : I. Synthesis and characterization of (chloromethyl)arsine

Abstract (Chloromethyl)arsine, ClCH2Ash2, can be prepared by the reduction of chloromethylarsonic acid. Bromomethyl and iodomethyl analogs could not be prepared. NMR, IR, and mass spectra data are included.

Dynamic NMR study of dimethylarsenic condensation reactions

Abstract Dimethylarsine, (CH3)2AsH, and dimethylhalo(or pseudohalo)arsines, (CH3)2AsX, X = Cl, Br, I or CN, reversibly form tetramethyldiarsine and HX in benzene. As followed by pmr spectroscopy, several pmr-rapid processes are observed which involve the exchange of parts among equilibrium components. Where available, equilibrium and thermodynamic parameters have been obtained. The activational parameters for the exchange processes suggest that exchange occurs through an associative intermediate. When X = Br or I, significant quantities of H2 are also found.

The optimization of yield in cluster synthesis. The preparation of [η5-C5H5)Fe(CO)]4

Abstract Yields of nearly 80% of the tetrameric cluster, [CpFe(CO)] 4 can be obtained from the dimer, [CpFe(CO) 2 ] 2 , through the catalytic action of triphenylphosphine combined with uv irradiation. Conduction of the reaction in m -xylene proved critical to obtain high yields. In halocarbon solvents, triphenylphosphine was catalytically ineffective, and the tetramer was obtained as its radical cation.

Copper Catalysis in the Methylenation of Arsenic Trichloride and Arsenic Tribromide.

Abstract Dramatic increases in yields of methylene-insertion products in the reactions of diazomethane with arsenic trichloride and arsenic tribromide were achieved through the use of copper catalysis. Mono-and bis-insertion products, XCH2AsX2 and (XCH2)2AsX (X = C1 or Br), but no tris-halomethyl arsines were obtained. The success of the procedure depends upon the use of ether solvent reclaimed from previous reactions.

Synthesis and NMR spectra of 2,2,2-trideuterioethylarsine and 2,2,2-trideuterioethylcyclopentaarsine

Abstract Pentakis(2,2,2-trideuterioethyl)cyclopentaarsine (PDECA) was synthesized by the reaction of 2,2,2-trideuterioethylarsine with dibenzylmercury. Variable temperature NMR spectra in C 6 D 6 are interpreted in terms of fast pseudorotation. NMR and mass spectra and synthesis of 2,2,2-trideuterioethylarsine are also described.