George E. Ryschkewitsch

Chlorination of trimethylamine borane. Synthesis of trimethylamine dichloroborane

Abstract Trimethylamine borane can be chlorinated with a variety of halides and oxyhalides under mild conditions. Reactivity decreases in the order SbCl5∼ SO2Cl2 > SbCl3 > SOCl2 > HgCl2 > HCl > (CH3)3 NH . HCl, and correlates well with thermodynamic properties of the halogenating agents. Reactivity towards chlorination in the amine boranes decreases in the order (CH3)3NBH3>(CH3)3NBH2Cl>(CH3)3NBHCl2, and correlates well with B stretching frequencies and nmr shifts. Trimethylamine dichloroborane was synthesized and characterized for the first time. The weaker halogenating agents appear to react via a polar hydride transfer mechanism whereas the strongest ones are likely to halogenate by a free radical chain mechanism.

Crystal structures of two N-methyltriphenylphosphoranimines: triphenylphosphine-N-methylimine borane, Ph3PN(CH3)BH3 and N,N-dimethylaminotriphenylphosphonium tetrafluoroborate, [Ph3PN(CH3)2]+BF4−

Abstract X-ray crystal structure determinations of two N-methyltriphenylphosphoranimines, Ph3PN(CH3)BH3 (1) and [Ph3PN(CH3)2]+BF4− (2), were carried out to determine the effects of π-bonding between P and N in triphenylphosphoranimines, Ph3PNR, as a function of formal chargeon the N atom. Crystals of 1 are monoclinic, space group P2 1 /n with a = 11.370(2), b = 10.507(2), c = 14.360(4) A and β = 91.47(2)° with Z = 4. Bond lengths of interest are: PN 1.605(3), NB 1.583(5), NC 1.456(5), average PC(phenyl) 1.805(3) A. Bond angles of interest are: PNC 124.2(2), PNB 120.7(2), CNB 114.6(3), average CPC 106.8(5), average CPN of 112.0(5)°. Crystals of 2 are monoclinic, space group P2 1 /c with a = 16.379(3), b = 16.777(2), c = 14.481(2) A and β = 94.41(1)° with Z = 8 (2 molecules per asymmetric unit). Average bond lengths of interest are: PN 1.626(4), PC(phenyl) 1.795(7), NC 1.442(13) A. Average bond angles are: CPC 109(2), CPN 110(2), PNC 123(3), CNC 112.8(4)°. The longer PC distances, the shorter PN distance and smaller CPC angles in 1 compared to 2 are consistent with changes in the s-character around the P atoms.

Complexes of hexamethylphosphoramide with mercury(II) salts

Abstract The isolation and characterization of the complexes of hexamethylphosphoramide and HgCl 2 , HgBr 2 , Hg(CN) 2 and Hg(CF 3 COO) 2 , is described. The compounds are weak and they are partially dissociated in solution. 1 H and 31 P NMR studies seem to show the existence of a fast exchange among the several types of ligands present in these systems. IR studies indicate that the coordination of mercury to HMPA is occurring at the phosphoryl group, as is usual for other complexes and products of the ligand.

Hexamethylphosphoramide-boron compounds. A new type of boronium cation

Abstract Hexamethylphosphoramide adducts of BF 3 and BCl 3 have been characterized. Reactions with BBr 3 and Bl 3 are complex and result in cleavage of the PN bond as implicated by the isolation of {[(CH 3 ) 2 N] 3 PO·BH 2 ·[(CH 3 ) 2 N] 2 P(I)O}I. hexamethylphosphoramide is only capable of cleaving the boron-halogen bond in amine-haloboranes for the bromine and iodine species. Boronium cations like {amine·BH 2 ·[(CH 3 ) 2 N] 3 PO} + , [amine·BH{[(CH 3 ) 2 N]PO} 2 2+ , (amine = (CH 3 ) 3 N; C 5 H 5 N; pCH 3 C 5 H 4 N) have been isolated and studied. last cation is the first example of a boronium cation containing one nitrogen and two oxygen bases.

Metal-dinitrogen tetroxide reactions in acetonitrile and dimethylsulphoxide

Abstract Magnesium and bismuth react with dinitrogen tetroxide in acetonitrile solution to give acetonitrile adducts of magnesium and bismuth nitrates. With excess dinitrogen tetroxide, bismuth reacts to form a bismuth nitrate adduct which can be decomposed to give anhydrous bismuth nitrate. Many metals which do not react with dinitrogen tetroxide in acetonitrile do react in dimethylsulphoxide, probably as a consequence of the greater co-ordinating ability of dimethylsulphoxide toward both dinitrogen tetroxide and the metal cation formed in the reaction. Antimony gives a white, deliquescent substance having the composition expressed by the formula SbO(NO 3 )·(CH 3 ) 2 SO, bismuth, a colourless crystalline substance with a composition expressed by the formula Bi(NO 3 ) 3 ·3(CH 3 ) 2 SO. Molybdenum is oxidized to the +6 oxidation state, and a yellow crystalline compound of unknown structure having the unusual stoicheiometry 4MoO 3 ·5(CH 3 ) 2 SO is formed. Lead reacts readily to give lead nitrate. Aluminium, titanium, iron, nickel, chromium, tin, arsenic, silicon and selenium show little or no tendency to react with dinitrogen tetroxide in dimethylsulphoxide.

Iron complexes with isocyanoboryl ligands

Abstract Two stable complexes of C 5 H 5 Fe(CO) 2 with the ligand isocyanoborohydride and the new ligand trimethylamine-isocyanoborane have been characterized. Shifts in the CN stretching frequency are interpreted in terms of N-coordination and metal-cyanide backbonding.

SYNTHESIS AND CHARACTERIZATION OF THE FIRST BORANE ADDUCTS AND BORON CATIONS OF SOME N-ALKYL AND N-AMINOTRIPHENYLPHOSPHORANIMINES

Abstract The first borane adducts of N-alkyl and N-aminotriphenylphosphoranimines, Ph3P[dbnd]N—R, were prepared by two different general synthetic methods. The first method involved displacement of THF (tetrahydofuran) from THF-borane by the free imines, and the second employed the reaction of LiBH4 with iminium bromides, Ph3P[dbnd]N(R)HBr, in diethyl ether. Imine boranes, Ph3P[dbnd]N(R)BH3, were synthesized where R [dbnd] methyl, ethyl, n-propyl, isopropyl, isobutyl, t-butyl. dimethylamino, phenylamino, and methyl, phenylamino as the nitrogen attached groups. Symmetrical boron cations, (Ph3P[dbnd]NR)2, BH2 +, where R = methyl, ethyl, and n-propyl, were synthesized by displacement of iodide from in-situ generated iodoborane adducts, Ph3P[dbnd]N(R)BH2I, by the free imines. An attempt to form an unsymmetrical boron cation from (CH3)3 NBH2I and Ph, P[dbnd]N(n-C3H7) resulted only in a mixture of the corresponding symmetrical boron cations. Physical, chemical and spectral properties of the borane adducts and b...

The reactions of dinitrogen tetroxide with lithium carbonate with a series of magnesium compounds, and with aluminium chloride

Abstract The reactions of liquid dinitrogen tetroxide with lithium carbonate, basic magnesium carbonate, magnesium oxide, magnesium hydrodixe, hydrated magnesium chloride, magnesium perchlorate and anhydrous aluminium chloride have been carried out. New methods for the preparation of anhydrous lithium nitrate and magnesium nitrate have been indicated. Evidence has been obtained for the formation of dinitrogen tetroxide adducts of magnesium nitrate and aluminium nitrate.