Mary E. Harman

Complexes of functionalised phosphine ligands. Part 1. Complexes of FeIII, CoIII, NiII and ReV with tridentate Schiff bases having PNO, NNO and NNS donor sets. Crystal structures of 2-(Ph2PC6H4NCH)C6H4OH and [Co{2-(Ph2PC6H4CHN)C6H4O}2][PF6]

The Schiff bases 2-[Ph2P(CH2)nNCH]C6H4OH (n= 3, HL1 or 2 HL2), 2-(RCHN)C6H3(OH)X-4 (R = 2-Ph2PC6H4, X = H HL3; R = 2-C5H4N, X = H HL4; R = 2-C5H4N, X = Cl HL5) were synthesised from the appropriate amine and aldehyde. On deprotonation these all functioned as tridentate monoanionic ligands to give complexes [FeL2]+ and [CoL2]+ with FeIII and CoIII and neutral complexes of stoichiometry NiL2 with NiII. The iron complexes were examined by Mossbauer spectroscopy which indicated the presence of two iron sites in [FeL12]+ with a spin-state equilibrium dependent on both temperature and the counter ion. The complex [FeL32]+ showed a single iron site, again with a spin state dependent on counter ion and temperature. The crystal structures of HL3 and [CoL32]+ have been determined. The distortions in free HL3 predispose it for co-ordination in a fac geometry to the Co with cis-PPh2 groups, and the changes occurring on co-ordination are discussed in detail. Reaction of RCHO (R = 2-Ph2PC6H4 or 2-C5H4N) with 2-aminobenzenethiol gave stable thiazoles R[graphic omitted]-2 which did not ring open to give tridentate ligands even on reaction with base and/or metal ions.

Synthesis, electrochemistry and complexation studies of new redox active bisferrocene acyclic and macrocyclic thioethers

Abstract The syntheses and electrochemical studies of new bisferrocene acyclic and macrocyclic ligands are described. Preliminary coordination investigations with palladium(II) and rhodium(I) transition metals produced, in most cases, polymeric complex species. Mono- and bimetallic copper(II) complexes of two macrocyclic ligands and a nickel(II) complex of an acyclic analogue have been isolated and characterized.

The preparation and characterization of some imido- and diazenido-rhenium complexes of maltol. The x-ray crystal structure of [Re(maltol)2(NPh)(PPh3)][BPh4]

Abstract The imido complex [ReCl3(NPh)(PPh3)2] reacts with excess maltol to give the green complex [Re(maltol)2(NPh)(PPh3)][BPh4] (1). Under analogous conditions, [ReCl2(N2COPh)(PPh3)2] gives [ReCl(maltol)(N2COPh)(PPh3)2] (2). An X-ray crystal structure of complex 1 revealed a distorted octahedral structure with cis-maltol ligands. Preliminary X-ray data on a poorly diffracting crystal of complex 2 has confirmed the formulation and stereochemistry. The possible structures of products from other precursors are discussed together with their redox and spectroscopic properties.

The synthesis, fluxional properties and X-ray crystal structure of [WI(CO)(C4H3N2S)(η2-MeC2Me)2] (where [C4H3N2S]− = pyrimidine-2-thionate)

Abstract Reaction Of [WI2(CO)(NCMe)(η2-MeC2Me)2]· 1 2 CH2Cl2 with one equivalent of K[C4H3N2S] (C4H3N2S = pyrimidine-2-thionate) in diethyl ether at room temperature affords the monoiodide product [WI(CO)(C4H3N2S)(η2-MeC2Me)2] (1) in high yield. The molecular structure of 1 has been crystallographically determined and is best described as a distorted octahedron, with one of the but-2-yne ligands lying trans to the iodide and both of them occupying the axial positions, and the remaining alkyne, carbon monoxide and the sulphur and nitrogen atoms of the pyrimidine-2-thionate ligand occupying the equatorial positions. Variable-temperature 1H NMR spectroscopic studies have shown the complex [WI(CO)(C4H3N2S)(η2-MeC2Me)2] (1) to be fluxional. 13C NMR spectroscopy indicates that the alkyne ligands donate a total of six electrons to the tungsten in 1.

Camphor-derived β-ketophosphine complexes of rhodium(III) and iridium(III); x-ray crystal structure of cis,mer-trichlorobis[(1R)-endo-(+)-3-diphenylphosphinocamphor]rhodium(III) chloroform()

Reaction of (1 R )- endo -(+)-3-diphenylphosphinocamphor (L) with RhCl 3 ·3H 2 O in ethanol gives trans,mer -[RhCl 3 L 2 ] and in THF gives cis,mer -[RhCl 3 L 2 ]. L reacts with IrCl 3 ·3H 2 O to give trans,mer -[IrCl 3 L 2 ]. On reaction with excess AgBF 4 , trans,mer -[IrCl 3 L 2 ] gives cis,trans -[IrCl 2 L 2 ]BF 4 . The complexes were characterized by IR, 1H and 31 P NMR spectroscopy. Trans,mer -[MCl 3 L 2 ] (M = Rh or Ir) and cis,mer -[RhCl 3 L 2 ] show both unidentate and bidentate binding of L (through phosphorus and carbonyl oxygen atoms) and cis,trans -[IrCl 2 L 2 ]BF 4 , shows only bidentate binding. The compound cis,mer -[RhCl 3 L 2 ] has been characterized crystallographically. The complex is a distorted octahedron about rhodium with the three chloride ligands having meridional geometry, and the ligand phosphorus atoms being cis to one another. The RhP bond length for the bidentate ligand is 2.339(6) A and for the unidentate ligand is 2.268(6) A. The bite angle for the bidentate ligand is 81.8(4)°.

Reactions of the bis(alkyne) complexes [Wi2(CO)(NCMe)(η2-RC2R)2](R = Me or Ph) with mono- and bi-dentate phosphine-donor ligands and the X-ray crystal structure of [Wl2(CO){Ph2P(CH2)PPh2}(η2-MeC2Me)]

Reaction of the complexes [Wl2(CO)(NCMe)(η2-RC2R)2](R = Me or Ph) either with 2 equivalents of L{L = PMe3, PEt3, PBun3, PMe2Ph, PMePh2, PEt2Ph, PEtPh2, PPh2(CH2CHCH2)[(PPh3) and PPh2(C6H11) for R = Me only]} or 1 equivalent of L2{L2= Ph2P(CH2)nPPh2(n= 1,2,3,4, or 6) or [Fe(η5-C5H4PPh2)2] for R = Me only} in CH2Cl2, at room temperature affords good yields of the compounds [Wl2(CO)L2(η2-RC2R)](1)–(24) by successive substitutions of acetonitrile and an alkyne ligand. X-Ray crystallographic studies were carried out on the complex [Wi2(CO){Ph2P(CH2)PPh2}(η2-MeC2Me)](19). Crystals of (19) are monoclinic, space group P21/n with a= 12.208(4), b= 13.395(2), c= 20.820(6)A, and β= 104.31(2)°. The structure was refined to R= 0.052 (R′= 0.060) for 2 860 reflections with Fo < 3σ(Fo). The tungsten co-ordination may be described in terms of a pseudo-octahedral structure. The bidentate phosphine ligand, but-2-yne, and an iodide ligand occupy the four equatorial sites, and the carbonyl and iodide ligands the two axial sites. The but-2-yne ligand is oriented so that it is approximately coplanar with the axial ligands. Phosphorus-31 n.m.r. and i.r. spectral studies are interpreted to suggest the likely structures for the other [Wl2(CO)L2(η2-RC2R)] complexes. The barrier to but-2-yne rotation of a number of complexes has been determined by variable-temperature 1H n.m.r. spectroscopy. These results are discussed in terms of the electronic and steric effects of the phosphorus-donor ligands and also the di-iodo complexes are compared with the analogous dibromo and dichloro complexes reported by other workers. The 13C n.m.r. chemical shifts of the alkyne contact carbons suggest that the alkyne ligand is acting as a four-electron donor in these complexes.

Synthesis and crystal structure of new tetrathiafulvalene derivatives incorporated into thiacrown ether macrocycles

Condensation of 2-thioxo-1,3-dithiole-4,5-dithiolate dianion 2 with 1,5-dibromo-3-thiapentane gave largely the 2:2 macrocycle 4 which could be converted into the novel tetrathiafulvalene-cage macrocycle 5 on treatment with triethyl phosphite. Treatment of the dithiolate dianion 2 with 1,9-dibromo-3,7-dithianonane gave the 1 :1 macrocycle 6 which could be converted into the planar tetrathiafulvalene derivative 7. The cyclic voltammogram of 7 showed a marked response on the addition of silver perchlorate, but no response when alkali metal perchlorates were added. Crystal structures of macrocycles 3 and 5 are also reported.

Synthesis and lithiation of γ,γ-difunctionalised ketene dithioacetals. Access to a new synthetic equivalent of a β-hydroxy-β-lithioacrylate. X-Ray molecular structure of 2-(1,3-dithian-2-ylidenemethyl)-1,3-dithiane

A series of γ,γ-dithioalkyl or dithioaryl ketene dithioacetals (3a), (3b), and (3c) has been prepared. Attempts to generate allylic anions under a variety of conditions from 1,1,3,3-tetrakis(phenylthio)propene (3a) and 1,1,3,3-tetrakis(methylthio)propene (3b) failed but 2-(1,3-dithian-2-ylidenemethyl)-1,3-dithiane (3c) is readily deprotonated with lithium di-isopropylamide to give anion (4c). This species can function as an equivalent of β-hydroxy-β-lithioacrylate and this equivalence has been illustrated by a synthesis of (±)-dihydrokawain (14). The use of compound (3c) as a reagent in synthesis is, however, limited in some cases by the nature of the conditions required for dithioacetal–ketone conversion. The X-ray crystal structure of compound (3c) has been determined.

Reactions of nucleophiles with bis(µ-thiosulphato-S)-bis(dinitrosylferrate)(2–), [Fe2(S2O3)2(NO)4]2–, and of electrophiles with heptanitrosyltri-µ3-thio-tetraferrate(1–), [Fe4S3(NO)7]–: new routes to bis(µ-organothiolato)-bis(dinitrosyliron) complexes [Fe2(SR)2(NO)4] and the crystal and molecular structure of trimethylsulphonium heptanitrosyltri-µ3-thio-tetraferrate(1–), SMe3[Fe4S3(NO)7]

Sodium bis(µ-thiosulphato-S)-bis(dinitrosylferrate)(2–), Na2[Fe2(S2O3)2(NO)4], reacts rapidly in aqueous solution with a range of thiols RSH [R = alkyl (C1–C5), CH2CO2Me, CH2CH2OH, or 2-pyrimidinyl] in the presence of sodium thiosulphate to give the neutral complexes [Fe2(SR)2(NO)4] generally in yields of 50–65%. With sodium sulphide a mixture of the Roussin red and black salts, Na2[Fe2S2(NO)4] and Na[Fe4S3(NO)7] respectively, is formed, readily separable by solvent extraction with diethyl ether. The latter salt reacts with arenediazonium tetrafluoroborates RN2+BF4– to yield the corresponding bis(µ-arenethiolato)-bis(dinitrosyliron) complexes [Fe2(SR)2(NO)4]. Alkylation of Na[Fe4S3(NO)7] with R3O+BF4–(R = Me or Et) yields [Fe2(SR)2(NO)4] but with Me3S+BF4– or Me3SO+ BF4– metathesis, rather than alkylation, occurs to provide Me3S+(or Me3SO+)[Fe4S3(NO)7]–. Crystals of [SMe3][Fe4S3(NO)7] are triclinic, with space group P, a= 9.655(2), b= 11.707(3), c= 8.968(1)A, α= 106.11(2), β= 91.78(3), γ= 84.92(2)°, and Z= 2: The compound is a salt with no close contacts between cation and anion. Reduction of the anion in [SMe3][Fe4S3(NO)7] to the more nucleophilic dianion causes alkylation and formation of [Fe2(SMe)2(NO)4].

Synthesis and characterisation of zirconium complexes with the diphosphinophosphide ligands –P(CH2CH2PR2)2(R = Me or Et); crystal structure of bis[bis(2-dimethylphosphinoethyl)phosphido]pentachlorohydridodizirconium(IV)

A new high-yield selective synthesis of the ditertiary phosphino secondary phosphines P(CH2CH2PR2)2H (R = Me or Et) has been developed. Following deprotonation, the multidentate anionic phosphides have been applied to the synthesis of new classes of zirconium and hafnium phosphides New compounds of the form [ZrCl2L2], [Zr2Cl6L2], [Zr2Cl5HL2] and [Zr2Cl3L3][L =–P(CH2CH2PMe2)2]are reported and are characterised by spectroscopic and analytical methods. The crystal structure of the hydrido complex has been determined and shows a binuclear structure containing bridging phosphide and hydride ligands.