Derivatives Trans Research Articles

Reaction of tungsten complexes [(.eta.5-C5H4R)Cl2W.tplbond.WCl2(.eta.5-C5H4R)] (R = Me, CHMe2) with alkynes: x-ray crystal structures of [(.eta.5-C5H4Me)2W2Cl4(.mu.-C4Me4)] and [(.eta.5-C5H4Me)2W2Cl2(O)(.mu.-C4Me4)

The dimers [(η 5 -C 5 H 4 R) 2 W 2 Cl 4 ] (1a, R=Pr i ; 1b, R=Me) react with an excess of but-2-yne (C 2 Me 2 ) to give the flyover bridge compounds cis-[(η 5 -C 5 H 4 R) 2 WCl 4 (μ-C 4 Me 4 )] (2a,b), which undergo thermal rearrangement in solution or in the solid state to the isomeric trans species (3a,b). The X-ray crystal structure of 3b reveals a planar bridging μ-C 4 Me 4 group that lies symmetrically perpendicular to the W-W (2.9295 (7) A) bond. Hydrolysis of 2 or 3 gives the monooxoditungsten derivatives trans-[(η 5 -C 5 H 4 R) 2 W 2 Cl 2 (O)(μ-C 4 Me 4 )] (4a,b)

Substitution Reactions of Hexachloro γ5-diazadiphosphetidines - First Examples of Hexa(alkoxy)/(aryloxy) Derivatives, [RNP(OR′)3]2

Abstract The reactions of the hexachloro γ5-diazadiphosphetidine, [(MeN)PCl3]2 (I) with NaOR′ (R = Ph or CH2CF3) lead to the isolation of the hitherto unprecedented hexa-(alkoxy)/(aryloxy) derivatives, [(MeN)P(OR′)3]2 (II) which have been characterized by mass spectrometry and NMR (1H and 31P) spectroscopy. The structure of the trifluoroethoxy derivative (II, R′ = CH2CF3) has been confirmed by single crystal X-ray analysis. Analogous reactions of the N-phenyl derivative [(PhN)PCl3]2 afford only the monophosphazenes, PbN=P(OR′)3. Aniline reacts with I in a Kirsanov type of reaction accompanied by ring opening to give a bis(phosphineimino)diphosphazane derivative, (PhN=)(NHPh)(NHMe)PN(Me)-P(NHPh)2(=NPh). The X-ray crystal structure of a related cyclic derivative trans-[PhNP(NMe2)(=NPh)]2 has been determined. The N2P2 ring and the aryl groups attached to the ring nitrogen atoms are coplanar; the exocyclic P=N bond (151.8 pm) is much shorter than the other P-N bonds (162.5, 169.8 pm).

Synthesis of (4 S,5 S)- trans-4-(cyclopentadiene-1-methyl)-5-diphenylphosphine-2,2-dimethyl-1,3-dioxolane and the ferrocene derivative; trans-[Feη-C 4H 4CH 2[ [formula omitted]H]CH 2PPh 22

The syntheses of the chiral cyclopentadiene compound (4 S,5 S)- trans-4-(cyclopentadiene-1-methyl)-5-diphenylphosphine-2,2-dimethyl-1,3-dioxolane ( 4) and of the related ferrocenylphosphine derivative trans-[Feη-C 5H 4CH 2[CHOC(CH 3) 2OCH]CH 2PPh 2 2] ( 5) are described.

Functionalized isocyanides as ligands. Part 5. Syntheses and reactions of 3-(benzylphosphonio)indolin-2-ylidene complexes of platinum(II). X-Ray crystal structure of trans-[Pt{o-CN(H)C6H4C[P(CH2Ph)2Ph]}X(PPh3)2]BF4·2C2H4Cl2(X = Cl or Br)

Reactions of the isocyanide o-ClCH2C6H4NC with benzylphosphines, PR3= P(CH2Ph)Ph2, P(CH2Ph)2Ph, or P(CH2Ph)3, in acetone at room temperature in the presence of excess of LiBr, yield the benzylphosphonium-substituted isocyanides [o-R3PCH2C6H4NC]Br, which are converted to the less hydroscopic tetrafluoroborate salts [o-R3PCH2C6H4NC]BF4(L)[PR3= P(CH2Ph)Ph2(L1), P(CH2Ph)2Ph (L2), or P (CH2Ph)3(L3)] upon reaction with excess NaBF4 in acetone. The ligands, L, react with a mixture of cis- and trans-[PtCl2(PPh3)2] and NaBF4 to form the cationic complexes trans-[Pt(L)Cl(PPh3)2] BF4[(1a)–(3a) for L1–L3]. Treatment of complexes (1a)–(3a) with a 10-fold excess of NEt3 in CH2Cl2 at room temperature leads to the cyclization reaction of the isocyanide ligands via phosphorus-ylide intermediates with the formation of 3-(benzylphosphonio)indolin-2-ylidene derivatives trans-[Pt{o-[graphic omitted](PR3)}Cl(PPh3)2]BF4[PR3= P(CH2Ph)Ph2(1b), P(CH2Ph)2Ph (2b), or P(CH2Ph)3(3b)]. Complexes (1a)–(3a) and (1b)–(3b) were characterized by their elemental analyses, i.r., 1H, and 31P n.m.r. spectra. The structure of trans-[Pt{o-[graphic omitted][P(CH2Ph)2Ph]}X(PPh3)2]BF4·2C2H4Cl2(X = Cl or Br) was determined by X-ray diffraction: space group C2, a= 21.946(1), b= 14.097(3), c= 19.801(1)Å, β= 96.95(1)°, Z= 4, R= 0.037 (R′= 0.041) for 4 802 independent reflections. The co-ordination geometry around the PtII atom is square planar with the indole ligand perpendicular to the plane. The Pt–C(sp2) distance is 2.036(8)Å. The bond lengths within the condensed system indicate extensive electronic delocalization. Complex (1b) reacts with aqueous KOH in acetone at room temperature to give, in high yield, the platinaheterocycle [[graphic omitted]HPh)Ph2]}Cl(PPh3)](1c). Chloride abstraction by AgBF4 from (1c) and reaction of the cationic intermediate with OH–, CO, and PPh3 afford the corresponding derivatives (1d), (1e), and (1f), respectively.

Zero valent molybdenum and tungsten ethylene isocyanide complexes: Synthesis and structural properties

Compounds of composition trans, mer-[M(C 2H 4) 2(CNR)(PMe 3) 3] ( 1) and trans, trans, trans-[M(C 2H 4) 2(CNR) 2(PMe 3) 2] ( 2) for various combinations of M = Mo, W and R = CHMe 2, CMe 3 and C 6H 11, have been obtained by the stepwise reaction of trans-[M(C 2H 4) 2(PMe 3) 4] with the corresponding isocyanide. Compounds 2 can also be obtained by treatment of 1 with CNR, a reaction that allows the synthesis of the mixed isocyanide trans, trans-[Mo(C 2H 4) 2(CNCMe 3)(CNC 6H 11)(PMe 3) 2] ( 2g). A similar reaction, starting with trans, mer-[M(C 2H 4) 2(CO)(PMe 3) 3], produces the mixed isocyanide—carbonyl derivatives trans, trans-[M(C 2H 4) 2(CNR)(CO)(PMe 3) 2] ( 3). X-ray structural studies on complexes 2b and 3b (M = Mo, R = CMe 3) have been carried out. Both compounds are monoclinic, P 2 1/ n but while the structure of 3b has been refined to a conventional R value of 0.034 by using 2976 observed reflections (unit cell constants: a = 10.972(3), b = 18.923(4), c = 10.544(3) Å; β = 98.89(2)°) extensive disorder problems have prevented anisotropic refinement of 2b, and a final isotropic R value of 0.097 has been obtained. For compound 3b, the MoC bond distances are 1.959(5) (MoCO), 2.137(4) (MoCNR) and 2.283(9) Å (av. MOC 2H 4).

Oxidative addition of OH bond to a metal centre: synthesis and crystal structure of trans-(PhO)(H)Pd(PCy 3) 2·PhOH

(Cy 3P) 2Pd (Cy = C 6H 11) reacts with PhOH in toluene to give the phenoxopalladium(II) hydride derivative trans-(PhO)(H)Pd(PCy 3) 2·PhOH; the crystal structural study has established that the oxygen of the phenoxy group forms a hydrogen bridge with an uncoordinated phenol molecule, and has allowed direct location of the hydride atom (Pd&.sbnd;H, 1.57(2) Å).

N-protonated 2-pyridylnickel(II) complexes insertion of isocyanides into the nickel2-pyridyl bond

The reaction of the binuclear complex [NiCl(μ-2-py)(PPh 3)] 2 (μ-2-py = μ-C 5H 4N- C 2, N) with the phosphines L (L = PPh 3, PMePh 2, PMe 2Ph or PEt 3) or dppe (= 1,2-bis(diphenylphosphino)ethane) in the presence of HClO 4 yields the N-protonated 2-pyridyl derivatives trans-[NiCl(2-pyH)(L) 2]ClO 4 or [NiCl(2-pyH)(dppe)] ClO 4 (2-pyH = C 5H 5N- C 2) with a square-planar coordination around the nickel(II) center. These products are largely associated through hydrogen bonding between the NH group and the perchlorate anion, both in the solid and in chlorinated solvents. The configuration in solution has been studied by 1H and 31P NMR spectroscopy. In the complex trans-[NiCl(2-pyH)(PMe 2Ph) 2]ClO 4, the planar 2-pyH ligand is oriented perpendicularly to the coordination plane, with restricted rotation about the Ni C 2 bond. The reaction of rans-[NiCl(2-pyH)(PMePh 2) 2]ClO 4 with CNC 6H 4OMe- p and then with NEt 3 yields the unstable compound trans-[NiCl{C(2-py)NC 6H 4OMe- p}(PMePh 2) 2] through a fast migratory insertion of the isocyanide into the nickel2-pyridyl bond. This product can be isolated and characterized only when the imino(2-pyridyl)methyl group is σ,σ′- N, N′-chelated to ZnCl 2.

Further studies on organonickel compounds: the synthesis of some new alkyl-, acyl- and cyclopentadienyl-derivatives and the crystal structure of trans-[Ni(CH 2SiMe 3) 2(PMe 3) 2

The complex [NiCl 2(PMe 3) 2] reacts with one equivalent of mg(CH 2CMe 3)Cl to yield the monoalkyl derivative trans-[Ni(CH 2CMe 3)Cl(PMe 3) 2], which can be carbonylated at room temperature and pressure to afford the acyl [Ni(COCH 2CMe 3)Cl(PMe 3) 2]. Other related alkyl and acyl complexes of composition [Ni(R)(NCS)(PMe 3) 2] (R = CH 2CMe 3, COCH 2CMe 3) and [Ni(R)(η-C 5H 5)L] (L = PMe 3, R = CH 2CMe 3, COCH 2CMe 3; L = PPh 3, R = CH 2CMe 2Ph) have been similarly prepared. Dialkyl derivatives [NiR 2(dmpe)] (R = CH 2SiMe 3, CH 2CMe 2Ph; dmpe = 1,2-bis(dimethylphosphine)ethane, Me 2PCH 2 CH 2PMe 2) have been obtained by phosphine replacement of the labile pyridine and NNN′N′-tetramethylethylenediamine ligands in the corresponding [Ni(CH 2SiMe 3) 2(py) 2] and [Ni(CH 2CMe 2Ph) 2(tmen)] complexes. A single-crystal X-ray determination carried out on the previously reported trimethylphosphine derivative [Ni(CH 2SiMe 3) 2(PMe 3) 2] shows the complex belongs to the orthorhombic space group Pbcn, with a = 14.345(4), b = 12.656(3), c = 12.815(3) Å, Z = 4 and R 0.077 for 535 independent observed reflections. The phosphine ligands occupy mutually trans positions P-Ni-P 146.9(3)° in a distorted square-planar arrangement.

ChemInform Abstract: TETRACARBONYL DIAZAPHOSPHOLE COMPLEXES OF GROUP 6B METALS: THE ROLE OF STERIC EFFECTS

AbstractDie thermische Substitution von (IIa) mit weiteren Mengen des cis‐Diaza‐ , phospholliganden L′ liefert eine cis‐trans‐2 : 3‐Mischung der Tetracarbonylkomplexe (I) mit Gesamtausb.

The aquation and trans-influence of phosphites in complexes of ruthenium(II)

The complexes trans-[Ru(NH 3) 4(P(OR) 3) 2] 2+ and trans-[Ru(NH 3 4P(OEt) 3P(OR) 3] 2+, where R = methyl, isopropyl and butyl, aquate via a common mechanism to yield, in each system, a single monophosphite complex as the product. The rate constants range from 9.2 × 10 −5 sec −1 (OEtRuO iPr) to 1.2 × 10 −5 sec −1 (OMeRuOMe), (25 °C, μ = 0.10, C H + = 10 −1–10 −4 M). With the complexes containing two different phosphorus ligands, the aqaution generates only the most stable monophosphite complex. The formal reduction potentials for tetraammineruthenium (III)–(II) couples with trimethyl, tributyl, and triisopropyl phosphite as ligands are +0.74, +0.67 and +0.66 V, respectively (25 °C, μ = 0.10, C H + = 10 −1–10 −4 M. The complexes trans-[Ru(NH 3) 4P(OR) 3(H 2O)] + exhibit an absorption band at 316 nm (ϵ < 8 × 10 2 M −1 cm −1) attributed to d-d transitions and the derivatives trans-[Ru(NH 3) 4P(OR) 3pz] 2+ present ligand-to-metal charge-transfer bands near 366 nm, respectively, (ϵ > 3 × 10 3 M −1 cm −1). The association constants for the complexes trans-[Ru(NH 3) 4P(OR) 3pz] 2+, measured spectrophotometrically, increase according to the following sequence: P(OMe) 3 < P(OEt) 3 < P(OBut) 3 < P(O iPr) 3. The formal potentials for the Ru(III)/ Ru(II) couples of the monophosphite complexes studied and the formation constants for the derivatives trans-[Ru(NH 3) 4P(OR) 3pz] 2+ strongly suggest the relevance of the d π electrons in the ruthenium (II)—phosphite bond. The extention of Ru(II) → P(III) back-bonding for these phosphite complexes decrease as follow: P(OMe) 3 > P(OEt) 3 > P(OBut) 3 > P(O iPr) 3.

Tetracarbonyl diazaphosphole complexes of group 6B metals: the role of steric effects

Thermal substitution reactions of [M(CO)5L1c] with cis diazaphosphole derivatives (L1= 3,4-dihydro-2,3,4,5-tetraphenyl-2H-1,2,3-diazaphosphole, L1c and L1t denote cis and trans L1 respectively) have yielded a mixture of cis and trans(2 : 3 ratio) tetracarbonyl complexes in which the ligands are bonded through the phosphorus atom. In contrast the reactions of [M(CO)5L1t] with the bulkier trans diazaphosphole isomers (L1t or L2t, L2= 5-benzyl-3,4-dihydro-2,3,4-triphenyl-2H-1,2,3-diazaphosphole) have only afforded the trans disubstituted tetracarbonyl [M(CO)4(Lt)2]. On the other hand, L1t and L2t have reacted with [M(CO)5L1c] affording the mixed-phosphine derivatives trans-[M(CO)4L1cLt](Lt= L1t or L2t). The norbornadiene complex [Mo(CO)4(nbd)] produced only cis-[Mo(CO)4(L1c)2] when treated with L1c in cyclohexane at room temperature, whereas with L1t no tetracarbonyl complexes (cis or trans) have been observed. In addition it has been found that cis(or trans)-[Mo(CO)4(L1c)2] thermally interconverts by a dissociative pathway to the trans(or cis)-[Mo(CO)4-(L1c)2] to give an equilibrium composition (cis : trans= 2 : 3) whereas trans-[Mo(CO)4(Lt)2] did not isomerize. All these different stereochemical results are tentatively explained by invoking fluxional or rigid five-co-ordinate intermediates in which only steric factors play a decisive role in determining the geometry and then the products distribution. The nature of the complexes has been established essentially by i.r. and 1H n.m.r. spectra. An X-ray study on cis-[Mo(CO)4(L1c)2] is also reported.

NEW BIS(CROWN ETHER)S DERIVED FROM STEREOISOMERS OF DICARBOXYLIC ACID

Abstract Stereoisomers of bis(crown ether)s were synthesized from meso- or dl-α,α′-dimethylglutaric acid and maleic or fumaric acid. Preliminary solvent extraction data suggested that the maleate derivative(cis form) differs considerably in the cation-complexing ability from the fumarate derivative(trans form), while two isomers of α,α′-dimethylglutarate derivatives are almost the same.