Joseph Chatt

A convenient synthesis of 1,2-bis(dichlorophosphino)ethane, 1,2-bis(dimethylphosphino)ethane and 1,2-bis(diethylphosphino)ethane

Abstract A simple synthesis of 1,2-bis(dimethylphosphino)ethane, 1,2-bis(diethyl-phosphino)ethane, and 1,2-bis(dicyclohexylphosphino)ethane is reported. The method involves the synthesis of 1,2-bis(dichlorophosphino)ethane using a procedure patented by Toy and Uhing; the halide is allowed to react with the appropriate Grignard reagent to give the required tetraalkyldiphosphine. The phosphines produced in this way are moderately sensitive to air but not spontaneously inflammable as previously reported.

Improved preparation of tertiary phosphine and related substitution products of group VI metal carbonyls

Abstract The substitution of carbon monoxide in the Group VI metal carbonyls by tertiary phosphines, arsines, stibines or certain tertiary amines in boiling ethanol is strongly catalysed by sodium borohydride. This catalysis has been used to prepare a wide range of known and new substituted carbonyls of chromium, molybdenum and tungsten.

Diazoalkane complexes of tungsten from the condensation of hydrazido Complexes with Ketones

Abstract Hydrazido(2−) and hydrazido(1−) complexes of tungsten condense with ketones, R 1 R 2 CO, in the presence of catalytic amounts of acid to yield complexes containing the groups W = NN = CR 1 R 2 and WNHN =CR 1 R 2 respectively. The other ligands are halide ions and monotertiary phosphines. These new complexes yield secondary amines and ammonia on reduction with LiAlH 4 ; acids produce nitrogen-free tungsten materials, hydrazine and azines.

Rhodium(I), rhodium(III), palladium(II), and platinum(II) complexes containing ligands of the type PRnQ3–n(n= 0,1, or 2; R = Me, Et, But, or Ph; Q = CH2OCOMe or CH2OH)

We report the characterisation of the phosphines PRnQ3–n(n= 0,1, or 2; R = Me, Et, But, Or Ph; Q = CH2OCOMe or CH2OH) and of their complexes with halides of PtII, PdII, RhI, and RhIII. The methylene protons of the acetoxymethyl- and hydroxymethyl-groups show no 31P–1H coupling in the complexes, and this is attributed to |2J(PH)+4J(PH)| being accidentally nearly zero. Although the phosphines render the complexes more soluble in hydroxylic solvents than complexes of more conventional phosphines, and complexes derived from phosphines containing two or more hydroxymethyl groups are water soluble, the new complexes were not found to possess exceptional or unusual catalytic properties for the hydrogenation or isomerisation of olefins.

Diazene-N-(di-imide) and hydrazido-(2–)N-(aminoimido) complexes: the addition of acids to dinitrogen complexes

The protonation and reduction of dinitrogen in a mononuclear complex are described. The diazene compounds [MX2(N2H2)(dpe)2](I; M = W, X = Cl or Br; M = MO, X = Br; dpe = Ph2PCH2CH2PPh2), and hydrazido (2–)N complex salts, [Mo(N2H2)(depe)2]X (X = Cl or Br; depe = Et2PCH2CH2PEt2) and trans-[WCl(N2H2)(PMe2Ph)4]Cl were prepared by the reaction of trans-[M(N2)2(diphos)2](M = MO or W; diphos = dpe or depe) or cis-[W(N2)2(PMe2Ph)4] with an excess of the appropriate hydrogen halide. Compounds (I) contain labile halogen and are converted into the hydrazido-(2–)N complex salts [MX(N2H2)(dpe)2]Y (Y = BPh4, ClO4, or PF6, M = W; Y = BF4, M = MO) by treatment with NaBPh4, LiClO4, NaPF6, or [NEt4]BF4 as appropriate. The structural implications of the i.r., 1H and 31P n.m.r. spectroscopic properties of the N2H2 compounds and of their 15N analogues are discussed.With only 2 mol equiv. of HCl, trans-[W(N2)2(dpe)2] gives the hydride [WH(N2)2(dpe)2]HCl2 and trans-[Mo(N2)2(dpe)2] gives the dihydride [MoH2Cl2(dpe)2]. [WH(N2)2(dpe)2]HCl2 is converted into [WH2Cl2(dpe)2] in refluxing methanol and [WCl2(N2H2)(dpe)2] gives [WCl2{N2H(COCH3)}(dpe)2] with acetyl chloride or acetic anhydride.This work provides the first chemical evidence that dinitrogen is as likely to be reduced at a mono- as at a bi-metal site in nitrogenase.

The reactions of dinitrogen in its mononuclear complexes

Abstract Until recently dinitrogen in its mononuclear complexes was thought to be almost as inert as elementary nitrogen, but recently we have shown that in the bis-dinitrogen complexes of molybdenum and tungsten it reacts with acids in a protic medium under ambient conditions to yield up to 90% ammonia. With some organic halides it gives good yields of organonitrogen products and, with dimethylsulphate in methanol, methylamines and methylhydrazines. These reactions and events leading to their discovery are described.

New synthetic routes to mono-, di- and tri-carbonyl halido complexes of rhenium(I) and rhenium(III) with tertiary phosphine

Abstract Carbonylation of tertiary phosphine complexes under reducing conditions is shown to be a reliable and direct route to rhemium mono- and poly-carbonyl complexes.

The reactions of isonitrile complexes of molybdenum(0) and tungsten(0) with alkylating agents to give carbyne (aminomethyne) complexes

Abstract Treatment of the complexes trans -[M(CNMe) 2 (dppe) 2 ] (A, M = Mo or W; dppe = Ph 2 PCH 2 CH 2 PPh 2 ) with MeFSO 3 , Me 2 SO 4 or [Et 3 O] BF 4 in benzene gives the complexes trans -[M(CNRMe)(dppe) 2 ]X (B, R = Me or Et; X = FSO 3 , MeSO 4 or BF 4 ). Dialkylated compounds were not observed. The compounds B isomerise in CH 2 Cl 2 solution to give cis -[M(CNRMe)(dppe) 2 ]X. Spectroscopic data are reported for the complexes and are used to deduce their structures.

Reactions of coordinated nitride to generate novel rhenium and molybdenum imido complexes: The crystal and molecular structures of [Mo(NCPh3)(S2CNMe2)3)]BF4 and [Mo(NSO2Ph)(S2CNMe2)3]PF6

Abstract The nitrido complexes [MoN(S 2 CNR 2 ) 3 ] (R 2  Me 2 , Et 2 ) and [ReN)S 2 CNR 2)2 -(PMe 2 Ph) n ] (R 2  Me 2 ; Et 2 ; n  0, 1) react with halides R′X (R′  PhCO, PhSO 2 , 2,4-(NO 2)2 C 6 H 3 , 2,4-(NO 2)2 C 6 H 3 S; X  Cl, R′  Me, X  I), [R′3 O ]BF 4 (R′  Me, Et) or [Ph 3 C]BF 4 to give the imido complexes [Mo(NR′)(S 2 CNR 2 ) 3 ]+ and [Re(NR′)(S 2 CNR 2 ) 2 (PME 2 Ph) n ] (R′  Me, Et, Ph 3 C + , PhSO 2 , PhCO, 2,4(O 2 N) 2 -C 6 H 3 , 2,4-(O 2 N) 2 C 6 H 3 S); the X-ray crystal structures of [Mo(NCPh 3 )(S 2 -CNMe 2 )3]BF 4 and [Mo(NSO 2 Ph)(S 2 CNMe 2 )3]PF 6 have been determined. Both complexes have approximately pentagonal bipyramidal geometries although the NSO 2 Ph complex is more distorted. The NCPh 3 and NSO 2 Ph complexes have MoNC and MoNS angles of 175.1(5) ° and 161.3(13)° and MoN distances of 1.731(2) and 1.70(2)A, respectively.

Diazenido (iminonitrosyl) (N2H), Hydrazido(2-) (N2H2, and hydrazido(1-) (N2H3) ligands as intermediates in the reduction of ligating dinitrogen to ammonia

Abstract Complexes of molybdenum and tungsten containing the ligands N2H, N2H2 and N2H3, have been obtained from dinitrogen complexes, and probably represent intermediate stages in the reduction of ligating dinitrogen to ammonia.