[Fp(CH)], [η-CpRu(CO)(CH)], and [η-CpOs(CO)(CH)]: A Complete Set of Group 8 Metal-Methane Complexes.

Here, we report the NMR spectroscopic analysis of the group 8 transition metal methane σ-complexes [η-CpM(CO)(CH)][Al(OC(CF))] (M = Fe, Ru) at -90 °C in the weakly coordinating solvent 1,1,1,3,3,3-hexafluoropropane. The iron(II)-methane complex has a H resonance at δ -4.27, a C resonance at δ -53.

Binding methane to a metal centre.

The σ-alkane complexes of transition metals, which contain an essentially intact alkane molecule weakly bound to the metal, have been well established as crucial intermediates in the activation of the strong C-H σ-bonds found in alkanes. Methane, the simplest alkane, binds even more weakly than larger alkanes. Here we report an example of a long-lived methane complex formed by directly binding methane as an incoming ligand to a reactive organometallic complex.

Observation and Analysis of Large Dynamic Frequency Shifts in the H NMR Signals of H-D in Deuterium-Substituted Dihydrogen Complexes.

A dynamic frequency shift (DFS) in the H NMR resonance of the HD unit of the deuterium-labeled dihydrogen complex [Ru(D)(η-HD)(PP)][BPh] [PP = P(CHCHCHPPr)] has been observed and analyzed. To the best of our knowledge, this is the first demonstration of the DFS for a H-D pair. The observed DFS of the center line relative to the outside lines in the H-D triplet is large, up to ∼11 Hz, because of the short H-D distance encountered in dihydrogen complexes.

Dinuclear acetylide-bridged ruthenium(ii) complexes with rigid non-aromatic spacers.

Rigid dinuclear ruthenium complexes containing non-aromatic caged and polycyclic spacer groups were synthesised and characterised. The complexes, [trans,trans-{Ru(dmpe)2(C[triple bond, length as m-dash]CtBu)}2(μ-C[triple bond, length as m-dash]C-X-C[triple bond, length as m-dash]C)], where X = 1,4-bicyclo[2.2.

Reduction of Dinitrogen to Ammonia and Hydrazine on Low-Valent Ruthenium Complexes.

The ruthenium(0) dinitrogen complexes [Ru(N)(PP)] [PP = P(CHCHPR); R = Pr or Cy] react with triflic acid and other strong acids to afford mixtures of ammonia and hydrazine. In this reaction, Ru(0) is oxidized to Ru(II), and depending on the solvent, Ru(II) benzene or triflate complexes are isolated and characterized from the reactions with triflic acid as the final metal-containing products from the reaction. The Ru(II) products are isolated and reduced back to Ru(0) dinitrogen complexes providing a cycle for the reduction of coordinated dinitrogen.

Nitrogen fixation revisited on iron(0) dinitrogen phosphine complexes.

A reinvestigation of the treatment of [Fe(N2)(PP)2] (PP = depe, dmpe) with acid revealed no ammonium formation. Instead, rapid protonation at the metal center to give hydride complexes was observed. Treatment of [Fe(N2)(dmpe)2] with methylating agents such as methyl triflate or methyl tosylate resulted in methylation of the metal center to afford [FeMe(N2)(dmpe)2](+).

Ruthenium hydrides containing the superhindered polydentate polyphosphine ligand P(CH2CH2P(t)Bu2)3.

The complex RuH2(N2)(P(2)P3(tBu)) (1) containing the extremely bulky PP3-type ligand P(2)P3(tBu) = P(CH2CH2P(t)Bu2)3 was synthesized by reduction of RuCl2(P(2)P3(tBu)) (2) with Na/NH3 under a N2 atmosphere. Like other complexes containing the P(2)P3(tBu) ligand, only three of the four donor phosphines are coordinated, and one of the phosphines remains as a dangling pendant phosphine. Reduction of RuCl2(P(2)P3(tBu)) (2) with a range of the more usual hydride reducing agents afforded the previously unknown ruthenium hydride complexes RuHCl(P(2)P3(tBu)) (3), RuH(BH4)(P(2)P3(tBu)) (6), RuH(AlH4)(P(2)P3(tBu)) (7), and the ruthenium(II) trihydride K[Ru(H)3(P(2)P3(tBu))] (8).

Low oxidation state iron(0), iron(I), and ruthenium(0) dinitrogen complexes with a very bulky neutral phosphine ligand.

The synthesis of a series of iron and ruthenium complexes with the ligand P(2)P3(Cy), P(CH2CH2PCy2)3 is described. The iron(0) and ruthenium(0) complexes Fe(N2)(P(2)P3(Cy)) (1) and Ru(N2)(P(2)P3(Cy)) (2) were synthesized by treatment of [FeCl(P(2)P3(Cy))](+) and [RuCl(P(2)P3(Cy))](+) with an excess of potassium graphite under a nitrogen atmosphere. The Fe(I) and Ru(I) species [Fe(N2)(P(2)P3(Cy))](+) (3) and RuCl(P(2)P3(Cy)) (4) were synthesized by treatment of [FeCl(P(2)P3(Cy))](+) and [RuCl(P(2)P3(Cy))](+) with 1 equiv of potassium graphite under a nitrogen atmosphere.

Base-induced dehydrogenation of ruthenium hydrazine complexes.

Treatment of [RuCl(PP(3)(iPr))](+)Cl(-) (PP(3)(iPr) = P(CH(2)CH(2)P(i)Pr(2))(3)) with hydrazine, phenylhydrazine, and methylhydrazine afforded side-on bound hydrazine complexes [RuCl(η(2)-H(2)N-NH(2))(η(3)-PP(3)(iPr))](+), [RuCl(η(2)-H(2)N-NHPh)(η(3)-PP(3)(iPr))](+), and [RuCl(η(2)-H(2)N-NHMe)(η(3)-PP(3)(iPr))](+). The analogous reactions of [RuCl(2)(PP(3)(Ph))] (PP(3)(Ph) = P(CH(2)CH(2)PPh(2))(3)) with hydrazine, phenylhydrazine, and methylhydrazine afforded end-on bound hydrazine complexes [RuCl(η(1)-H(2)N-NH(2))(PP(3)(Ph))](+), [RuCl(η(1)-H(2)N-NHPh)(PP(3)(Ph))](+), and [RuCl(η(1)-H(2)N-NHMe)(PP(3)(Ph))](+). Treatment of parent hydrazine complex [RuCl(N(2)H(4))(PP(3)(iPr))](+) with strong base afforded the dinitrogen and dihydride complexes [Ru(N(2))(PP(3)(iPr))] and [RuH(2)(PP(3)(iPr))].

Side-on bound complexes of phenyl- and methyl-diazene.

Treatment of trans-[FeCl(2)(dmpe)(2)] with phenylhydrazine and 1 equiv of base afforded the side-on bound phenylhydrazido complex cis-[Fe(η(2)-NH(2)NPh)(dmpe)(2)](+). Further deprotonation of the phenylhydrazido complex afforded the side-on bound phenyldiazene complex cis-[Fe(η(2)-HN═NPh)(dmpe)(2)] as a mixture of diastereomers. Treatment of cis-[RuCl(2)(dmpe)(2)] with phenylhydrazine or methylhydrazine afforded the end-on bound phenylhydrazine or methylhydrazine complexes cis-[RuCl(η(1)-NH(2)NHR)(dmpe)(2)](+) (R = Ph, Me).

New superhindered polydentate polyphosphine ligands P(CH2CH2P(t)Bu2)3, PhP(CH2CH2P(t)Bu2)2, P(CH2CH2CH2P(t)Bu2)3, and their ruthenium(II) chloride complexes.

The synthesis and characterization of the extremely hindered phosphine ligands, P(CH(2)CH(2)P(t)Bu(2))(3) (P(2)P(3)(tBu), 1), PhP(CH(2)CH(2)P(t)Bu(2))(2) (PhP(2)P(2)(tBu), 2), and P(CH(2)CH(2)CH(2)P(t)Bu(2))(3) (P(3)P(3)(tBu), 3) are reported, along with the synthesis and characterization of ruthenium chloro complexes RuCl(2)(P(2)P(3)(tBu)) (4), RuCl(2)(PhP(2)P(2)(tBu)) (5), and RuCl(2)(P(3)P(3)(tBu)) (6). The bulky P(2)P(3)(tBu) (1) and P(3)P(3)(tBu) (3) ligands are the most sterically encumbered PP(3)-type ligands so far synthesized, and in all cases, only three phosphorus donors are able to bind to the metal center. Complexes RuCl(2)(PhP(2)P(2)(tBu)) (5) and RuCl(2)(P(3)P(3)(tBu)) (6) were characterized by crystallography.

Ruthenium hydride complexes of the hindered phosphine ligand tris(3-diisopropylphosphinopropyl)phosphine.

The synthesis and characterization of the novel hindered tripodal phosphine ligand P(CH(2)CH(2)CH(2)P(i)Pr(2))(3) (P(3)P(3)(iPr)) (1) are reported, along with the synthesis and characterization of ruthenium chloro and hydrido complexes of 1. Complexes [RuCl(P(3)P(3)(i)Pr)][BPh(4)] (2[BPh(4)]), RuH(2)(P(3)P(3)(i)Pr) (3), and [Ru(H(2))(H)(P(3)P(3)(iPr))][BPh(4)] (4[BPh(4)]) were characterized by crystallography. Complex 2 is fluxional in solution, and low-temperature NMR spectroscopy of the complex correlates well with two dynamic processes, an exchange between stereoisomers and a faster turnstile-type exchange within one of the stereoisomers.

Synthesis and characterization of iron(II) and ruthenium(II) hydrido hydrazine complexes.

Treatment of trans-[MHCl(dmpe)(2)] (M = Fe, Ru) with hydrazine afforded the hydrido hydrazine complexes cis- and trans-[MH(N(2)H(4))(dmpe)(2)](+) which have been characterized by NMR spectroscopy ((1)H, (31)P, and (15)N). Both cis and trans isomers of the Fe complex and the trans isomer of the Ru complex were characterized by X-ray crystallography. Reactions with acid and base afforded a range of N(2)H(x) complexes, including several unstable hydrido hydrazido complexes.

Mixed-valence dinitrogen-bridged Fe(0)/Fe(II) complex.

The reactions of a dinitrogen-bridged Fe(II)/Fe(II) complex [(FeH(PP(3)))(2)(μ-N(2))](2+) (3) (PP(3) = P(CH(2)CH(2)PMe(2))(3)) with base were investigated using (15)N labeling techniques to enhance characterization. In the presence of base, 3 is initially deprotonated to the Fe(II)/Fe(0) dinitrogen-bridged complex [(FeH(PP(3)))(μ-N(2))(Fe(PP(3)))](+) (4) and then to the symmetrical Fe(0)/Fe(0) dinitrogen-bridged complex (Fe(PP(3)))(2)(μ-N(2)) (5). [(FeH(PP(3)))(μ-N(2))(Fe(PP(3)))](+) (4) exhibits unusual long-range (31)P-(31)P NMR coupling through the bridging dinitrogen ligand from the phosphines at the Fe(0) center and those at the Fe(II) center.

Side-on bound diazene and hydrazine complexes of ruthenium.

The reaction of cis-[RuCl(2)(PP)(2)] (PP = depe, dmpe) with hydrazine afforded end-on bound ruthenium(II) hydrazine complexes. Treatment of the hydrazine complexes with strong base afforded the side-on bound ruthenium(0) diazene complexes cis-[Ru(eta(2)-NH=NH)(PP)(2)]. Treatment of cis-[Ru(eta(2)-NH=NH)(depe)(2)] with weak acid under chloride-free conditions afforded the side-on bound hydrazine complex cis-[Ru(eta(2)-N(2)H(4))(depe)(2)](2+).

Rhodium(I) and iridium(I) complexes containing bidentate phosphine-imidazolyl donor ligands as catalysts for the hydroamination and hydrothiolation of alkynes.

A series of novel cationic and neutral rhodium and iridium complexes containing bidentate phosphine-imidazolyl donor ligands of the general formulae [M(ImP)(COD)]BPh(4) (M = Rh, ImP = ImP2, 3; ImP1a, 4a; ImP1b, 4b and M = Ir, ImP = ImP2, 5; ImP1a, 6a and ImP1b, 6b), [Ir(ImP)(CO)(2)]BPh(4) (ImP = ImP2, 7; ImP1a, 8a and ImP1b, 8b), [Rh(ImP1b)(CO)(2)]BPh(4) (10b) and [M(ImP)(CO)Cl] (M = Rh, ImP = ImP2, 11; ImP1b,12 and M = Ir, ImP = ImP2, 13; ImP1b, 14 ) where COD = 1,5-cyclooctadiene, ImP2 = 1-methyl-2-[(2-(diphenylphosphino)ethyl]imidazole, 1; ImP1a = 1-methyl-2-[(diphenylphosphino)methyl]imidazole, 2a and ImP1b = 2-[(diisopropylphosphino)methyl]-1-methylimidazole, 2b were successfully synthesised. The solid state structures of 3, 6a, 11 and 12 were determined by single crystal X-ray diffraction analysis. A number of these complexes are effective as catalysts for the intramolecular hydroamination of 4-pentyn-1-amine to 2-methyl-1-pyrroline.

Iron(0) and ruthenium(0) complexes of dinitrogen.

The synthesis of a series of iron and ruthenium complexes with the new ligand PP(i)(3) (1) P(CH(2)CH(2)P(i)Pr(2))(3) is described. The iron(0) and ruthenium(0) dinitrogen complexes Fe(N(2))(PP(i)(3)) (4) and Ru(N(2))(PP(i)(3)) (5) were synthesized by treatment of the iron(II) and ruthenium(II) cationic species [FeCl(PP(i)(3))](+) (2) and [RuCl(PP(i)(3))](+) (3) with potassium graphite under a nitrogen atmosphere. The cationic dinitrogen species [Fe(N(2))H(PP(i)(3))](+) (6) and [Ru(N(2))H(PP(i)(3))](+) (7) were prepared by treatment of 4 and 5, respectively, with 1 equiv of a weak organic acid.

Base-mediated conversion of hydrazine to diazene and dinitrogen at an iron center.

The treatment of the hydrazine complex cis-[Fe(N(2)H(4))(dmpe)(2)](2+) with base afforded the diazene complex cis-[Fe(N(2)H(2))(dmpe)(2)]. This reaction is reversed by the treatment of the diazene complex with a mild acid, while treatment of the hydrazine complex with a mixture of KOBu(t) and Bu(t)Li afforded the dinitrogen complex [Fe(N(2))(dmpe)(2)].

The first side-on bound metal complex of diazene, HN[double bond]NH.

The side-on bound metal complex of diazene cis-[Fe(NH[double bond]NH)(dmpe)(2)] was synthesised by reaction of [Fe(dmpe)(2)Cl(2)] with hydrazine in the presence of potassium graphite and characterised by (15)N NMR spectroscopy and X-ray crystallography.

Dinuclear alkynyllanthanoid(II) dications with pentaphenylcyclopentadienyl or tri-tert-butyldiphosphacyclopentadienyl counter ions.

Reaction of [Yb(CpPh5)(C[triple bond]CPh)(thf)]2 (CpPh5 = pentaphenylcyclopentadienyl), prepared from Yb(C triple bond CPh)2 and HCpPh5 or Yb metal, HgPh(C[triple bond]CPh) and HCpPh5, with a controlled amount of diglyme (dig), and of Eu(C triple bond CPh)2, P triple bond CBut and dig, yield the unusual organolanthanoid(II) dicationic complexes [Yb(C[triple bond]CPh)(dig)(thf)2]2[CpPh5]2.4thf and [Eu(C triple bond CPh)(dig)2]2[P2C3But3]2 respectively.

Reproductive parameters and life-history variables in captive golden-bellied mangabeys (Cercocebus agilis chrysogaster).

An understanding of the reproductive physiology of captive primates is vital for their successful management. We report on reproductive parameters and life-history variables collected at the Sacramento Zoo for five female golden-bellied mangabeys (Cercocebus agilis chrysogaster) over a 7-year period. For each female, we collected data on their sexual skins, menses, gestation, and other pregnancy-related factors, such as postconception bleeding and swelling.

An iron(II) dihydrogen hydrido complex containing the tripodal tetraphosphine ligand P(CH2CH2PMe2)3.

The dihydrogen hydrido complex [FeH(H2)(PP3)]+ 1 (PP3 = P(CH2CH2PMe2)3 2) was formed by the protonation of the dihydrido complex FeH2(PP3) 3 with methanol or ethanol. The observation of H-D coupling in partially deuterated isotopomers of 1 and measurement of T1 relaxation times for the hydrido and dihydrogen resonances of 1 confirmed the presence of the eta2-dihydrogen ligand. Complex 1 shows dynamic NMR behaviour in both the 31P and 1H NMR spectra with facile exchange between the protons in the eta2-dihydrogen ligand and the eta1-hydrido ligand.