Ph PCH Research Articles

Reactivity of {Ru(C5Me5)[η2‐P,O‐Ph2PCH2C(tBu)=O](CO)}[PF6] towards Terminal Alkynes and Unexpected Rearrangement of a Fischer‐Type Carbene Ligand

AbstractThe ruthenium complex {Ru(C5Me5)[η2‐P,O‐Ph2PCH2C(tBu)=O](CO)}[PF6] reacts with terminal alkynes HC≡CR (R = H, tBu, Ph) in methanol to afford {Ru[:C(OMe)CH2R](C5Me5)[η1‐P‐Ph2PCH2C(=O)tBu](CO)}[PF6] derivatives. The similar reaction conducted in dichloromethane as solvent led to six‐membered metallacyclic complexes{Ru(C5Me5)[η2‐C,P‐:C(CH2R)OC(tBu)=CH–PPh2](CO)}[PF6], which, when R is an aromatic group (R = Ph, p‐tolyl), rearrange under moderate thermal activation into {Ru(C5Me5)[η3‐C,C,P‐RCH=CH‐OC(tBu)=CHPPh2](CO)}[PF6] derivatives, according to an isomerization of a Fischer‐type carbene ligand into an η2‐coordinated vinylic ether, as shown by X‐ray single crystal analysis (R = p‐tolyl).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Synthesis and characterization of Sn(II), Pb(II) and Yb(II) complexes supported by [C(Ph2PNSiMe3){6-(2-RC5H3N)}]2− or [CH(Ph2PNSiMe3){6-(2-RC5H3N)}]− (R = 3,5-dimethyl-1-pyrazolyl or iminophosphoranyl) ligands

The synthesis and characterization of several tin(II), lead(II) and ytterbium(II) complexes supported by [C(Ph2P=NSiMe3){6-(2-RC5H3N)}]2- or [CH(Ph2P=NSiMe3){6-(2-RC5H3N)}]- (R = 3,5-dimethyl-1-pyrazolyl or iminophosphoranyl) ligands are reported. Reaction of 2-R-6-{CH2P(Ph2)=NSiMe3}C5H3N with M[N(SiMe3)2]2 (M = Sn, Pb) generated tin(II) and lead(II) complexes [M{C(Ph2P=NSiMe3){6-(2-RC5H3N)}}]2 [3, M = Sn, R = 3,5-dimethyl-1-pyrazolyl; 4, M = Pb, R = 3,5-dimethyl-1-pyrazolyl; 9, M = Sn, R = Me3SiN=P(Ph2); 10, M = Pb, R = Me3SiN=P(Ph2)]. When R = p-MeC6H4N=P(Ph2), a N,N-chelate tin(II) complex, [Sn{2-{N(p-MeC6H4)=PPh2}-6-{CHP(Ph2)=NSiMe3}}{N(SiMe3)2}] (11), was isolated. Treatment of 2-(Ph2P=NSiMe3)-6-{CH2P(Ph2)=NSiMe3}C5H3N with Yb[N(SiMe3)2]2(DME) afforded N,N,N-chelale ytterbium(II) complex [Yb{2-{N(SiMe3)=PPh2}-6-{CHP(Ph2)=NSiMe3}}{N(SiMe3)2}] (12). The complexes were characterized by elemental analyses and multinuclear NMR spectroscopy. Complexes 3, 4 and 10-12 were further characterized by single crystal X-ray diffraction techniques.

Bi- and Trinuclear Complexes of Group 4 Metal and Palladium Bridged by OPPh2Groups: Synthesis and High Catalytic Activities in Double Hydrophosphinylation of 1-Octyne

The early−late heterobinuclear complexes Cp2M(μ-OPPh2)2PdMe2 (M = Ti (1), Zr (2), and Hf (3)) were synthesized by the reaction of PdMe2(tmeda) (tmeda = Me2NCH2CH2NMe2) with respective metallocene diphosphinite ligands Cp2M(OPPh2)2 prepared from Cp2MCl2 (M = Ti, Zr, and Hf) and LiOPPh2. The complexes 1−3 catalyzed the addition (hydrophosphinylation) of HP(O)Ph2 to 1-octyne to give mainly not the single-addition product n-Hex-CH═CHP(O)Ph2 (4a) or n-Hex-C{P(O)Ph2}═CH2 (4b) but the double-addition product n-Hex-CH{P(O)Ph2}CH2P(O)Ph2 (5) at 40 °C in low yields. The yield of 5 was, however, substantially improved to >95% for 2 and 3 when tertiary phosphine PR3 such as PMePh2 was added to the catalytic system. The stoichiometric reaction of the complexes 1−3 with the phosphorus substrate HP(O)Ph2 and PMePh2 afforded in situ the trinuclear complexes H(PMePh2)Pd(μ-OPPh2)3M(μ-OPPh2)3PdH(PMePh2), which were found to exhibit the high catalytic activities similar to those of their parent complexes 1−3 in the presence of PR3 and were thus proposed to be a practical catalyst. On the basis of the above findings, simple mixtures of mononuclear Cp2MCl2 and PdMe2(tmeda) complexes together with PMePh2 could be used successfully as precatalysts for the double hydrophosphinylation of 1-octyne with HP(O)Ph2 to give satisfactory results comparable to those attained with the preorganized binuclear complexes 2 and 3 with PMePh2 added.

Complexes of Vanadium(V) Oxide Trifluoride with Nitrogen and Oxygen Donor Ligands: Coordination Chemistry and Some Fluorination Reactions

Abstract[VOF3(MeCN)], obtained by dissolving VOF3 in dry acetonitrile, is a useful synthon for the preparation of complexes of the oxide‐fluoride, and the reaction with 2,2′‐bipyridyl, 1,10‐phenanthroline, Me2N(CH2)2NMe2 and Ph2P(O)CH2P(O)Ph2 (L–L), or Ph3PO, Me3PO, Ph3AsO, pyridine and pyridine N‐oxide (L), produces the complexes [VOF3(L–L)] or [VOF3(L)2] respectively. These were characterised by microanalysis, IR, UV/Vis and multinuclear NMR [51V, 19F{1H}, 31P{1H}, 1H] spectroscopy, the data showing them to besix‐coordinate with trans F–V–F units and the neutralligands trans to O and F, respectively. X‐ray crystal structures of [VOF3(1,10‐phenanthroline)], [VOF3(Ph3PO)2] and [VOF3(pyNO)2] confirm the geometry, although the first two exhibit O/F disorder trans to the neutral ligand. Unstable complexes with ether and thioether ligands including [VOF3{MeO(CH2)2OMe}], [VOF3{MeS(CH2)2SMe}] and [VOF3(15‐crown‐5)] are also described; these decompose rapidly even in the solid state, with fluorination of the ligands. The [VOF3(Ph3AsO)2] also decomposes in solutionto a mixture of products including Ph3AsF2 and [V6O12F4(Ph3AsO)2(Ph2AsO2)2] identified crystallographically. Comparisons with complexes of VOCl3 are also described.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

1,1,1-Tris[(diphenylphosphoryl)methyl]propane monohydrate

The arrangement of phosphoryl groups and phenyl rings in the title compound, C2H5C[CH2P(O)Ph2]3·H2O or C42H41O3P3·H2O, is far from threefold symmetry. The P=O bond lengths are 1.4899 (12), 1.4926 (12) and 1.4927 (12) A. The O=P—C(methyl­ene) angles differ significantly from ideal tetra­hedral values, the maximum value being 117.08 (7)°. The C—C—C angles around the central C atom vary from 107.92 (12) to 111.91 (12)°. In the crystal structure, hydrogen bonds in which water mol­ecules act as proton donors link organic mol­ecules into chains along the [100] direction.

New anionic and dianionic polydentate systems featuring ancillary phosphinosulfides as ligands in coordination chemistry and catalysis

Abstract This article provides an overview of the chemistry of monoanionic S–P–S and dianionic S–C–S ligands featuring two phosphinosulfide ligands as pendant groups. These new pincer-type structures are easily assembled from phosphinines and the bis-sulfide derivative of the bis(diphenylphosphino)methane, respectively. Monoanionic S–P–S pincer ligands easily coordinate group 10 and group 9 metal fragments through displacement reactions. Palladium(II) complexes of S–P–S ligands efficiently catalyze cross-coupling processes, allowing the formation of boronic esters and biphenyl derivatives. Rh(I) complexes of S–P–S ligands react in a regioselective way with small molecules (O2, SO2, CS2, MeI) to afford the corresponding Rh(I) or Rh(III) derivatives. S–C–S dianonic ligands, which are readily obtained through a bis-metallation at the central carbon atom of Ph2P( S)CH2P( S)Ph2, react with Pd(II) and Ru(II) precursors to afford new carbene complexes. Samarium and thulium alkylidene complexes of these S–C–S dianionic ligands were synthesized in a similar way. Reaction of the lanthanide derivatives with ketones or aldehydes yields olefinic derivatives through a ‘Wittig-like’ process.

Synthesis and Properties of Complexes of Vanadium(V) Oxide Trichloride with Nitrogen‐ and Oxygen‐Donor Ligands

AbstractIntensely coloured, extremely moisture sensitive complexes [VOCl3(L)] (L = pyridine, quinoline, Ph3PO, Ph3AsO, pyridine N‐oxide), [VOCl3(L)2] (L = pyridine, Me3PO, pyridine N‐oxide), [VOCl3(L–L)] [L–L = 2,2′‐bipyridyl, 1,10‐phenanthroline, Ph2P(O)CH2P(O)Ph2, MeOCH2CH2OMe, 15‐crown‐5or Me2NCH2CH2NMe2] and [Cl3OV(μ‐L–L)VOCl3] [L–L =18‐crown‐6 or Ph2P(O)CH2P(O)Ph2] have been prepared from VOCl3 and the appropriate ligands in dichloromethane solution. These constitute the first extended series of complexes of vanadium(V) with neutral donor ligands. They have been fully characterised by analysis, IR, UV/Visible and multinuclear (1H, 31P, 51V) NMR spectroscopy, and their solution behaviour probed as a function of temperature using 51V NMR spectroscopy. Reducing ligands including phosphanes, arsanes, thio‐ and selenoethers immediately reduce VOCl3 to give VIV or VIII species. Oxygen atom transfer reactions of some of the complexes with Ph3P, Ph3As, Me2Se and Bu2S, leading to the corresponding ligand oxides are also described. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Enolate‐Phosphane Ligands Providing a Tool for the Selective Substitution of Triphenylphosphane by Carbon Monoxide or Trimethylphosphane in Complex {Ru(Cp)[η2‐P,O‐Ph2PCH2C(tBu)=O](PPh3)}[PF6], and Subsequent Reactivity Towards Terminal Alkynes

AbstractThe deprotonation under basic conditions of the keto‐phosphane ligand in complexes {Ru(Cp)[η1‐P‐Ph2PCH2C(=O)tBu](PPh3)(L)}[PF6] (L = CO or PMe3) that arise from the addition of L to {Ru(Cp)[η2‐P,O‐Ph2PCH2C(tBu)=O](PPh3)}[PF6] generates {Ru+(Cp)[η1‐P‐Ph2PCH=C(tBu)O–](PPh3)(L)} zwitterionic species, as shown by an X‐ray crystal structure determination (L = CO). The removal of the triphenylphosphane ligand is subsequently achieved under thermal activation to afford the neutral derivatives Ru(Cp)[η2‐P,O‐Ph2PCH=C(tBu)O](L). A further protonation step is sufficient to complete the formation of the new complex {Ru(Cp)[η2‐P,O‐Ph2PCH2C(tBu)=O](PMe3)}[PF6], which reacts in methanolat reflux with 1,1‐diphenyl‐2‐propyn‐1‐ol to afford thesix‐membered metallacyclic derivative {Ru(Cp)[η2‐C,P:C(CH=CPh2)OC(tBu)=CH–PPh2](PMe3)}[PF6], as shown by an X‐ray single crystal analysis. The synthesis of related η5‐indenyl ruthenium complexes and of {Ru(Cp)(=C=CH2)[Ph2PCH2C(=O)tBu](PR3)}[PF6] (PR3 = PPh3 or PMe3) vinylidene complexes is also reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Synthesis, spectroscopic studies and structural systematics of phosphine oxide complexes with Group II metal (beryllium–barium) nitrates

Complexes of the nitrates of beryllium, magnesium, calcium, strontium and barium with the phosphine oxides OPPh3, Ph2P(O)CH2P(O)Ph2, and o-C6H4(P(O)Ph2)2 have been prepared and characterised by analysis and IR spectroscopy and the structures of [Be(OPPh3)2(NO3)2], [Mg(OPPh3)2(NO3)2], [Ca{Ph2P(O)CH2P(O)Ph2}2(NO3)2] and [Ca{o-C6H4(P(O)Ph2)2}2(NO3)2] have been determined. The solution speciation has been probed by a combination of 1H, 31P{1H} and 9Be NMR spectroscopy and conductance measurements. The variation in speciation and stability from Be–Ba is interpreted in terms of changes in the charge/radius ratio of the cations—thus whilst Be and Mg interact strongly with the phosphinoyl ligands, strontium and especially barium have very limited affinity for these ligands, and the complexes are extensively dissociated in solution.

Synthesis of ROMP Monomers Containing Metal–Metal Bonds

Methods for the synthesis of cyclic monomers that have both metal–metal bonds and carbon–carbon double bonds are reported. Ring opening metathesis polymerization (ROMP) of these monomers would yield polymers that are photochemically degradable. The first method investigated involved substitution of Cp2Fe2(CO)4 by the bidentate phosphine ligand DPPEN (Ph2P $${-}$$ CH=CH–PPh2). Cp2Fe2(CO)2( $$\upmu$$ -DPPEN) was synthesized and the X-ray crystal structure is reported but the molecule could not be polymerized by a ROMP method using Grubbs’s catalyst. The inability of this monomer to polymerize (or copolymerize with cyclooctatetraene) was attributed to the bulky phenyl rings being in close proximity to the C=C in the DPPEN ligand, which prevents coordination of the monomer to the catalyst. To decrease the steric interactions, the DPPBN ligand was synthesized (DPPBN=Ph $$_{2}{-}$$ CH $$_{2}{-}$$ CH=CH $${-}$$ CH $$_{2}{-}$$ PPh2). However, the reaction of DPPBN with Cp2Fe2(CO)4 yielded the product Cp2Fe2(CO)2( $$\upmu$$ -1,2,4-triphos), where the 1,2,4-triphos ligand is a tridentate ligand formed by the formal additional of Ph2PH to DPPBN (1,2,4-triphos=Ph $$_{2}{-}$$ CH $$_{2}{-}$$ CH(PPh2) $${-}$$ CH $$_{2}{-}$$ CH $$_{2}{-}$$ PPh2). An X-ray structure of the Cp2Fe2(CO)2( $$\upmu$$ -1,2,4-triphos) complex revealed that the 1,2,4-triphos ligand chelates exclusively through the two phosphorus atoms that are bridged by two carbon atoms. It is suggested that this structural feature may simply reflect the increased stability of the 6-membered ring over the 7- and 8-membered rings. The reactions of the Cp2Mo2(CO)6 and Cp2Mo2(CO)4 dimers with DPPBN were investigated next. Reactions of Cp2Mo2(CO)6 and Cp2Mo2(CO)4 with the DPPEN and DPPBN ligands resulted in the disproportionation of the dimers. The X-ray crystal structure of [CpMo(CO)2(DPPEN)][CpMo(CO)3] was determined and is reported. The CpMo(CO)(DPPEN)Cl complex was formed when these same reactions were carried out in the presence of CH2Cl2. The X-ray crystal structure of this molecule is also reported.

Synthesis and Reactions of Mixed N,P Ligands

AbstractThe gold complexes [RN=C(R')CH(R)PPh2(AuCl)] (6a, R' = tBu; 6b, R' = Ad; R = SiMe3) were synthesised from the ketimines RN=C(R')CH(R)PPh2 (2a, R' = tBu; 2b, R' = Ad; R = SiMe3) and Me2SAuCl. The hydrolysis of the complexes to [H2NC(R')=CHPPh2(AuCl)] (8a, R' = tBu; 8b, R' = Ad) in protic solvents was studied and the reaction intermediate [H(R)NC(tBu)=CHPPh2(AuCl)] (7a) was isolated. The ketimines were further reacted with PhPCl2 to the cyclic phosphonium salts [Ph2PP(Ph)N(H)C(R')=CH]X (3a, R' = tBu, X = Cl; 3c, R' = Ad, X = Cl; 3d, R' = Ad, X = BPh4) and in the case of 3a oxidised with sulfur to give the ring‐opened β‐keto thiophosphane oxide Ph2P(S)CH2C(O)tBu (9). All compounds were fully characterised by NMR spectroscopy and in the case of 6b, 8a and 9 by X‐ray crystallography. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Synthesis and characterization of η3-allyl palladium(II) complexes with Ph2P(S)CHP(S)Ph2 and OC(CF3)CHCO(C4H3S) co-ligands

The new complexes [(η3-Me2CCMeCH2)Pd{η2-Ph2P(S)CHP(S)Ph2] (1), [(η3-Me2CCMeCH2)Pd{η2-OC(CF3) CHCO(C4H3S)}] (2) and [(η3-CH2CMeCH2)Pd{η2-OC(CF3)CHCO(C4H3S)}] (3) have been synthesized by reacting [(η3-allyl)Pd(μ-Cl)]2 with Ph2P(S)CH2P(S)Ph2 and OC(CF3)CH2CO(C4H3S) in the presence of base. All have been characterized by elemental analysis, FT-IR, 1H-n.m.r and FAB-mass spectroscopy. Spectroscopic studies suggest that both ligands are bidentate, forming six-membered Pd-S-P-C-P-S and Pd-O-C-C-C-O palladacycles, the η3-allyl group completing the coordination sphere.

Preparation and structures of [2-(dimethylamino)phenyl]diorganotin(IV) acetates substituted with organophosphorus groups in the α-position of the acetate ligand

Organotin(IV) carboxylates R2LNCSnOC(O)CH2P(E)Ph2, where LNC is an N-chelating 2-(dimethylamino)phenyl group, and R/E = Ph/void (1a), Ph/O (1b), Ph/S (1c), Me/void (2a), Me/O (2b) and Me/S (2c), were synthesized, characterized by 1H, 13C, 31P and 119Sn NMR, IR and MS spectra, and the solid-state structures of 1b, 1c, 2b and 2c were determined by single-crystal X-ray diffraction. Spectral and structural data showed that the compounds are monomeric in CDCl3 solution and the solid state, with the organophosphorus groups in the α-position of the monodentate carboxylate ligands not interacting with the tin atom. Copyright © 2005 John Wiley & Sons, Ltd.

Ionic Pt(II) Complexes Containing bis(Diphenylthiophosphinyl)methane

In this study, dipositive platinum(II) complexes of the general formula [Pt(L–L)(dppmS2)](ClO4)2, where dppmS2 = Ph2P(S)CH2P(S)Ph2 and L–L = dppm (Ph2PCH2PPh2), dppe (Ph2PCH2CH2PPh2), and dppp (Ph2PCH2CH2CH2PPh2), have been synthesized and characterized by 31P{1H} NMR, 13C NMR, IR spectra and elemental analyses.

Extraction of U(VI), Th(IV), Pu(IV), Am(III), and rare-earth elements from nitric acid solutions with diphenyl(dialkylcarbamoylmethyl)phosphine oxides substituted in the methylene bridge

The extractive power and selectivity of diphenyl(dialkylcarbamoylmethyl)phosphine oxides in extraction of U(VI), Th(IV), Pu(IV), Am(III), and rare-earth elements from nitric acid solutions was studied, as influenced by substitution of one or two hydrogen atoms in the methylene bridge with alkyl, cycloalkyl, CH2P(O)Ph2, and CH2C(O)NBu2 groups.

Tetrapodal Pentadentate Ligands with NS4 and NP4 Donor Sets: An Elusive Tetrathiol, and a Sterically Encumbered Tetraphosphane

With the intention of preparing tetrapodal pentadentate ligands having NS4 or NP4 donor sets, we investigated reactions of the previously reported tetratosylate 2,6-C5H3N[CMe(CH2OTs)2]2 (2) with thiourea or diphenylphosphide, but found them not to proceed cleanly, and to give mixtures of products. A derivative of 2 better suited to nucleophilic substitution is the corresponding tetrabromide 2,6-C5H3N[CMe(CH2Br)2]2(2,6-bis-(2-bromo-1-bromomethyl-1- methyl-ethyl)-pyridine, 3), which is obtained in excellent yield from 2 by treatment with LiBr in dimethylsulfoxide. The reaction of 3 with 4 eq of thiourea in refluxing ethanol gives a single product. Substitution is not quantitative, however, and the product likely is a bis(thiouronium) bis(bromide) salt. Similarly, the reaction of 3 with 4 eq of potassium O-ethyl xanthogenate displaces only two out of the four bromo substituents under the chosen conditions; workup then leads to what is formulated as a bis(thietane) derivative formed by intramolecular cyclisation. By contrast, nucleophilic substitution with NaSEt in ethanol is quantitative, and the thioether 2,6-C5H3N[CMe(CH2SEt)2]2(2,6-bis-(2-ethylsulfanyl-1-ethylsulfanylmethyl- 1-methyl-ethyl)-pyridine, 4) has been isolated in close to 60% yield. Likewise, and in spite of the considerable steric bulk amassed in the molecule, the reaction of 3 with an excess of KPPh2 in THF proceeds smoothly (even at -50 "C), to give the tetraphosphane 2,6-C5H3N[CMe(CH2PPh2)2]2(2,6-bis-{2-(diphenyl-phosphanyl)-1-[(diphenyl-phosphanyl)- methyl]-1-methyl-ethylg-pyridine, 5) in 65% yield. In order to assess possible pathways of oxidative degradation relevant to the coordination chemistry of this ligand, 5 was treated with NO in CH2Cl2 or ether at different temperatures. In two cases, reaction was observed to produce the oxide 2,6-C5H3N[CMe(CH2P(=O)Ph2)2]2 (6) as a colourless solid in near quantitative yield, with concomitant formation of N2O. All compounds have been characterised by 1H, 13C and 31P NMR spectroscopy (as applicable); IR spectroscopic and elemental analysis data are reported, and the crystal structure of 6 has been determined.

Heterofunctionalised phosphites built on a calix[4]arene scaffold and their use in 1-octene hydroformylation. Formation of 12-membered P,O-chelate rings

The calixarene phosphites L1–L4 were obtained in high yield through reaction of PCl3/NEt3 with the monofunctionalised cone-calixarenes p-tert-butylcalix[4]arene(OH)3OR, in which the R substituents bear an oxygen donor ligand [R = CH2P(O)Ph2 (L1), CH2CO2Et (L2), CH2C(O)NEt2 (L3), CH2CH2OMe (L4)]. The calixarene core of the four ligands adopts a cone conformation and, hence, the phosphites become potential P,O-chelating systems. Phosphite L1 is remarkably stable towards aqueous NaOH, but the presence of slightly acidic water results in phosphonate formation. Slow oxidation of L1 in air afforded the corresponding mixed phosphine oxide–phosphate. In the complexes [RuCl2(p-cymene)L1], [cis-PtCl2(L1)2] (9), trans-[PdCl2(L1)2], [Pd(8-mq)Cl(Ln)] (8-mqH = 8-methylquinoline, n = 1–3), [Pd(dmba)Cl(L1)] (dmbaH = N,N-dimethylbenzylamine), [Pd(η3-C4H7)Cl(L2)], [Rh(acac)(CO)Ln] (n = 1–3) and [RhCl(CO)(L1)2], the phosphites behave as a monodentate phosphorus donor ligands. Owing to their steric crowding, the two cis-disposed ligands of complex 9 cannot freely rotate about their coordination axis. In the solid state, the calixarene backbones of complex 9 display a so-called ‘up-up-out-up’ conformation. Chelating phosphite behaviour was found in the cationic complexes [Pd(8-mq)Ln]BF4 (n = 1–3). In solution, the large, chelating P,O-loop of the latter complexes swings from one side of the metal plane to the other, the dynamics possibly being facilitated by the flexibility of the calixarene backbone. The four oxo-functionalised phosphites were tested as catalysts for 1-octene hydroformylation. The observed reaction rates lie in the range reported for other medium-bulky phosphites. Furthermore, the hydroformylation rate decreases as the donor strength of the side group increases, suggesting binding of the O-donor during catalysis. The L/B ratios lie in the range 1.4–3.6, the highest linear aldehyde selectivity being observed with the phosphite ester L3.

Synthesis and Characterization of Dihydrogen(olefin)osmium Complexes with (E)-Ph2P(CH2)2CH=CH(CH2)2PPh2

Treatment of [OsClH3(PPh3)3] with (E)-Ph2P(CH2)2CH=CH(CH2)2PPh2 produced [OsClH(PPh3){Ph2P(CH2)2CH=CH(CH2)2PPh2}], which reacted with HOTf to give the dihydrogen(olefin) complex [OsCl(H2)(PPh3){Ph2P(CH2)2CH=CH(CH2)2PPh2}]OTf. Treatment of the latter complex with H2 did not result in hydrogenation of the olefin double bond, but gave the (hydrido)dihydrogen complex [OsH(H2)(PPh3){Ph2P(CH2)2CH=CH(CH2)2PPh2}]OTf. A density functional theory study suggested that hydrogenation of the double bond in [OsCl(H2)(PPh3){Ph2P(CH2)2CH=CH(CH2)2PPh2}]OTf was thermodynamically feasible but kinetically unfavorable. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

A meso-helical coordination polymer from achiral dinuclear [Cu2(H3CCN)2(micro-pydz)3][PF6]2 and 1,3-bis(diphenylphosphanyl)propane-synthesis and crystal structure of 1 to infinity Cu(mu-pydz)2][PF6 (pydz=pyridazine).

Reaction of achiral [Cu2(H3CCN)2(mu-pydz)3][PF6]2 (1) (pydz = pyridazine) with bidendate 1,3-bis(diphenylphosphanyl)propane (2) in acetonitrile at room temperature in a 1:1 ratio yielded the mononuclear copper(I) complex [Cu[CH2(CH2PPh2)2]2][PF6] (3) together with new one-dimensional coordination polymer 1 to infinity[[Cu(mu-pydz)2][PF6]] (4). Air-sensitive single crystals of 4, suitable for X-ray structure determination, were grown from a mixture of dichloromethane/ hexane [crystal system: monoclinic; space group: C2/c: a = 21.910(3), b = 12.130(2), c = 25.704(3) A,beta = 110.08(10) degrees, V = 6416.65(16) A3]. The one-dimensional coordination polymer 1 to infinity[[Cu(mu-pydz)2][PF6]] (4) exhibits as outstanding feature the rare structure of a meso-helix.

Iodo Derivatives of Bimetallic Fe—Pd and Fe—Pt Complexes. Crystal Structures of

Iodo derivatives of diphosphine-bridged heterobimetallic Fe—Pd and Fe—Pt complexeshave been prepared in which an alkoxysilyl ligand bridges the two metals in a μ2−η2-SiO manner. In the course of their synthesis by halide exchange from \(\) (dppx = dppm (Ph2 PCH2 PPh2) or dppa (Ph2PNHPPh2); M = Pd or Pt), loss of the alkoxysilyl ligand occurred resulting in the formation of complexes in which a bridging iodide has replaced, as a 3e−-donor, the bridging alkoxysilyl ligand. These complexes of formula \(\) (M = Pd, Pt are better prepared by reaction of \(\) with [MI2(cod)]. The crystal structures of \(\) (2a), \(\) (2b), and \(\) · CH2Cl2 (3b · CH2Cl2) have been determined by X-ray diffraction.