Unexpected oxidation of a diphos­phine by bis­(1,3‐diphenylpropane‐1,3‐dionato)­cobalt(II), [Co(dbm)2]

The reaction of bis­(1,3‐diphenylpropane‐1,3‐dionato)cobalt(II), [Co(dbm)₂], with bis­(diphenyl­phosphino)ethane (dppe) affords the coordination polymer catena‐poly[[bis­(1,3‐diphenyl­propane‐1,3‐dionato‐κ²O,O′)cobalt(II)]‐μ‐ethyl­enebis(diphenyl­phosphine oxide)‐κ²O:O′], trans‐[Co(C₁₅H₁₁O₂)₂(C₂₆H₂₄O₂P₂)]_n, as a result of oxidation of the diphos­phine. The Co atom is octa­hedral, with a CoO₆ coordination sphere, and the chelating dbm ligands adopt a trans configuration. The Co atom also lies on a centre of inversion, with a further symmetry centre bis­ecting the bridging ethyl­enebis(diphenyl­phosphine oxide) ligand.     

A nonrigid mixed-chelate complex of iron(0)

The reaction of Fe(CO)(CH₂ CHCHCH₂)₂ with (Ph₂ PCH₂)₂ results in formation of a $\text{4}\text{1}$ mixture of two isomers of Fe(CO)(CH₂ CHCHCH₂)-(Ph₂ PCH₂ CH₂ PPh₂). NMR studies concerning the structures of these isomers and their dynamic behavior in solution are described.     

Synthesis of ylideplatinum(II) complexes via α-functionalised alkylplatinum(II) intermediates and some comparative data on palladium(II) complexes; X-ray structure of trans-[Pt(CH2PEt3)I(PEt3)2]I

The reaction of [Pt(PEt₃)₃] with CH₂I₂ affords trans-[Pt(CH₂PEt₃)I(PEt₃)₂]I and is believed to proceed via the α-functionalised alkyl cis-[Pt(CH₂I)I(PEt₃)₂], because similar ylides are obtained from cis- or trans-[PT(CH₂X)(PPh₃)₂X] (XCl, Br, or I) with PR₃ (PEt₃, PBu₃ⁿ, PMePh₂, PEtPh₂, or PPh₃); cis-[Pd(CH₂I)-I(PPh₃)₂] does not react with excess PPh₃, but with PEt₃ yields trans-[Pd(CH₂PEt₃)I(PPh₃)₂]I; the X-ray structure of trans-[Pt(CH₂PEt₃)I(PEt₃)₂]I (current R = 0.045) shows PtP(1) 2.332(7), PtP(2) 2.341(8), PtC 2.08(2), and PtI 2.666(2) Å, and angles (a) C(1)PtI, P(1), P(2): 176.9(8), 91.6(6), 93.4(6), (b) IPtP(1), P(2): 87.1(2), 88.5(2), and (c) P(1)P(2), 166.8(3), and (d) PtC(1)P(3), 118(1)°.     

Acyl-platinum(II) and -palladium(II) complexes derived from 2-hydroxybenzaldehyde derivatives. X-ray structure of [Pt(OC6H4CO) (P(p-CH3C6H4)3)2]

Platinum(II) and palladium(II) complexes containing chelating acyl ligands have been synthesized from salicylaldehyde, 2-hydroxynaphthaldehyde and 2-hydroxy-3-methoxybenzaldehyde. The platinum(II) complexes [Pt(acyl)L₂], acyl  OC₆H₄CO, OC₁₀H₆CO, O(m-CH₃OC₆H₃CO), L  tertiary phosphine, 1/2 diphenylphosphinoethane, can be isolated with both monodentate and chelating diphosphines, whereas for palladium only the compounds with chelating phosphines are readily obtainable. The reactions of [Pt(OC₆H₄CO)L₂] with HCl afford trans-[PtCl(OHC₆H₄CO)L₂], L  monodentate tertiary phosphine and cis-[PtCl(OHC₆H₄CO)L₂], L2  1,2-bis-diphenylphosphinoethane, in which the metal—carbon bond remains intact. The structure of [Pt(OC₆H₄CO)-(P(p-CH₃C₆H₄)₃)₂] has been determined by X-ray diffraction methods and found to have the expected square planar structure. Some relevant bond lengths and angles are: PtP; 2.271(4) and 2.348(5) Å; PtC; 1.96(2) Å and PtO; 2.07(1) Å; PPtP  101°, CPtO  82°.     

A tetrahedrally coordinated cobalt(II) aminophosphonate containing one-dimensional channels

A tetrahedrally coordinated cobalt(II) phosphonate, Co(O₃PCH₂CH₂NH₂), has been synthesized using hydrothermal techniques. X-ray diffraction indicates that this material is a three-dimensional open framework with rings aligned along a single axis forming infinite one-dimensional channels. The framework decomposes just above 400 °C. Magnetic susceptibility data are consistent with weak antiferromagnetic ordering at low temperatures.     

New crystal forms of tris(2-aminoethanolato-O,N)cobalt(III): Structures and properties

Crystal forms of cobalt(III) tris(2-aminoethanolate) hydrates, i.e., red cubic crystals of the composition fac-[Co(NH₂CH₂CH₂O)₃] · 5.44H₂O (fac-I · 5.44H₂O) and blue prismatic crystals of the composition mer-[Co(NH₂CH₂CH₂O)₃] · 3H₂O (mer-I · 3H₂O) were studied by the ⁵⁹Co, ¹³C NMR and X-ray diffraction methods. It was found that mer-[Co(NH₂CH₂CH₂O)₃] · 3H₂O (mer-I · 3H₂O) is a new pseudopolymorphic modification of fac-[Co(NH₂CH₂CH₂O)₃] · 3H₂O (fac-I · 3H₂O), while fac-I · 3H₂O represents a new polymorphic modification of the complex mer-[Co(NH₂CH₂CH₂O)₃] · 3H₂O (mer-I · 3H₂O) described previously. The comparative analysis of the spectra revealed dynamic equilibrium between these geometric isomers; the fac-isomer is stable in aqueous solutions.     

Cyanoalkyl complexes of transition metals . : II. Preparation and properties of some platinum complexes containing phosphorus as a donor atom

cis-PtCl(CH₂CN)(PPh₃)₂ was obtained by the reaction of Pt(PPh₃)₄ with ClCH₂CN in acetone. A solution of Pt(PPh₃)₄ and ClCH₂CN in benzene was heated under reflux to give trans-PtCl(CH₂CN)(PPh₃)₂. The reaction of the trans-isomer with Br^?, I^?, Ph₂PCH₂CH₂ PPh₂, Ph₂PCH₂CH₂AsPh₂ and cisPh₂PCHCHPPh₂ has been examined. The trans-influence of a ligand trans to the CH₂CN group seems to be indicated by the ²J(PtH) of the CH₂CN protons. The τ values of trans-PtX(CH₂CN)(PPh₃)₂ and PtX(CH₂ CN)(PP) (X = Cl, Br, I) are related by a linear function.     

The chemistry of vinylphosphine chalcides: I. The Preparation of Diphenylvinylphosphine Oxide Tetracarbonyliron(0)

Reaction of diphenylvinylphosphine oxide with dodecacarbonyltriiron(0) gives Ph₂P(O)CHCH₂·Fe(CO)₄, in which coordination of the iron-containing moiety to the phosphine oxide is considered to take place through the carbon—carbon double bond of the latter.     

On the transferability of conformation in FC(O)S-containing compounds: Conformation and properties of methylfluorocarbonyl disulphide FC(O)SSCH3

Methylfluorocarbonyl disulphide, FC(O)SSCH₃, was prepared for the first time by reaction of FC(O)SCl with CH₃SH at room temperature. Infrared data for the vapour and matrices (Ar, Ne and N₂) as well as Raman, UV, mass and ¹⁹F, ¹³C and ¹H NMR spectra have been obtained and interpreted.From these data, the most stable conformer was deduced to have the gauche conformation with respect to the FC(O) and CH₃ groups with the syn conformation between the CO and SS bonds having C₁ molecular symmetry. This conformer is in equilibrium with another, possibly the corresponding anti, referring to the CO and SS bonds.The main structure found for FC(O)S-containing compounds seems to be the syn conformation.     

Cationic cobalt(I) carbonyl complexes containing secondary or tertiary phosphines. A direct synthesis from cobalt(II) salts

Cobalt(I) carbonyl complexes of formula [Co(CO)_n(P)_5?n]ClO₄ (n = 1, 2, 3; P = secondary or tertiary phosphine) have been prepared by reaction of CO under ambient conditions with Co(ClO₄)₂ · 6H₂O and phosphine in isopropyl alcohol. The chemical and spectroscopic properties of these complexes are described and the stoichiometry and mechanism of the carbonylation reaction discussed.     

Cobalt(I) and cobalt(III) derivatives from the reactions of phosphine ligands with cobalt(II) salts containing low-coordinating anions

Complexes of the type [Co(CO)_n(P)_5?n]ClO₄, [CoH₂(P)₄]ClO₄, [CoH(P)₅](ClO₄)₂ and [CoHX(F)₄]ClO₄ (P = secondary or tertiary phosphine) have been prepared from Co(ClO₄)₂·6 H₂O and phosphine in isopropyl alcohol.     

Metallorganische diazoalkane : XIII. Reaktionen metallorganischer diazoalkane mit P(NMe2)3 zu metallorganischen phosphazinen LnM(R)CNNP(NMe2)3

Staudinger reactions of 20 organometallic diazoalkanes and of their parent compounds CH₂N₂, HC(N₂)CO₂Et, HC(N₂)C(O)Me and HC(N₂)C(O)Ph with a strong basic phosphine P(NMe₂)₃ are described and were classified into five groups 1–5 of different reactivity.Mono-diazomethanes L_nMCHN₂ (for L_nM = Me₃Si, Me₂As) react to give (cis, trans) isomers of the corresponding phosphazines L_nMC(H)NNP(NMe₂)₃; a stepwise reaction of functional diazogroups in organometallic bis-diazoalkanes, e.g. Hg[C(N₂)CO₂Et]₂, has been observed.Different reactivity of organometallic diazoalkanes cannot be rationalized by known spectroscopic data but can be interpreted by steric effects. In analogy to reactions of isoelectronic azides a transition state of the Staudinger reaction is suggested with an attack of the basic phosphine at the electrophilic α-nitrogen atom and following rearrangement into the N_β-Staudinger adduct.Trimethylgermaniumdiazomethane, Me₃GeCHN₂, was obtained as a novel monosubstituted organometallic diazoalkane and is fully characterized.     

Molecular mechanics calculations for conformational energies and torional force constants in fluoro propenes and butenes

Experimental data on conformational energies of the molecules FH₂CHCCH₂, FH₂CFCCH₂, FH₂C(CH₃)C&.dbnd;CH₂ trans-FH₂CHCC(CH₃)H have been used to establish parameter values for the nonbonding atom ⋯ atom interaction F ⋯ C(sp²) within the Morse potential formulation. Torsional potentials have been calculated for the four molecules mentioned above and in addition for cis- and trans-FH₂CHCCHF, (FH₂C)₂CCH₂, cis-FH₂CHCCHCH₂F, CH₃FCHHCCH₂ and FH₂CCH₂HCCH₂. Calculated results have been compared with experimental values. Torsional force constants for the molecules have been obtained. A comparison between fluoro, chloro and bromo compounds is presented.     

Reagents for Organic Synthesis : Vol. 5; by M. Fieser and L.F. Fieser,Wiley-Interscience,New York/London/Sydney/Toronto, 1975, 864 pages, $32.15, £16.15.

Phosphorus-31 NMR and X-ray crystallography show that the two similar chelating triphosphine ligands PhP(CH₂CH₂PPh₂)₂(2,2-P₃) and PhP(CH₂CH₂CH₂ PPh₂)₂(33-P₃) form cobalt(I) complexes having trigonal-bipyramidal and square-pyramidal structures, respectively. The structures and PP coupling constants of [Co(33-P₃)(P(OMe)₃)CO]BF₄·1THF and [Co(22-P₃)(P(OMe)₃)₂]BF₄ are given, and the change from square-pyramidal geometry in [Co(33-P₃)P(OMe)₃)CO]⁺ to trigonal-bipyramidal in [Co(22-P₃)(P(OMe)₃)₂]⁺ may be rationalized in terms of a decreased “chelate bite angle” for the PhP(CH₂CH₂PPh₂)₂ ligand.     

Mercury(II) complexes of new bidentate phosphorus ylides: synthesis,spectra and crystal structures

The reaction of dppm (1,1-bis(diphenylphosphino)methane) with 2-bromo-4-phenylacetophenone and benzyl bromoacetate in chloroform produces new phosphonium salts, [Ph₂PCH₂PPh₂CH₂C(O) C₆H₄Ph]Br (I) and [Ph₂PCH₂PPh₂CH₂COOCH₂Ph]Br (II). By allowing the phosphonium salts to react with the appropriate base, the bidentate phosphorus ylides, Ph₂PCH₂PPh₂=C(H)C(O)C₆H₄Ph (III) and Ph₂PCH₂PPh₂=C(H)C(O)OCH₂Ph (IV), were obtained. The reaction of these ligands with mercury(II) halides in dry methanol led to the formation of the mononuclear complexes {HgX₂[(Ph₂PCH₂PPh₂C(H)C(O)C₆H₄Ph)]} (X = Cl (V); X = Br (VI); X = I (VII)) and {HgX₂[(Ph₂PCH₂PPh₂C(H)COOCH₂Ph)]} (X = Cl (VIII); X = Br (IX); X = I (X)). The FTIR and ¹H, ³¹P and ¹³C NMR spectra were studied. The structure of compound III was unequivocally determined by the single-crystal X-ray diffraction technique. Single-crystal X-ray analysis of the {HgBr₂[(Ph₂PCH₂PPh₂C(H)C(O)C₆H₄Me)]} complex (XI) revealed the presence of a mononuclear complex containing the Hg atom in a distorted tetrahedral environment. In all complexes, the ylides referred to above were coordinated through the ylidic carbon and the phosphine atom.     

Estimates for systematic empirical corrections of consistent 4–21G ab initio geometries and their correlations to total energy group increments

The structural parameters of the completely relaxed 4–21G ab initio geometries of more than 30 basic organic compounds are compared to experimental results. Some ranges for systematic empirical corrections, which relate 4–21G bond distances to experimental parameters, are associated with total energy increments. In general, for the currently feasible comparisons, the following corrections can be given which relate calculated distances to experimental r_g parameters and calculated angles to r_s-structures For CC single bond distances, deviations between calculated and observed parameters (r_g) are in the ranges of ?0.006(2) to ?0.010(2) Å for normal or unstrained hydrocarbons; ?0.011(3) to ?0.016(3) Å for cyclobutane type compounds; and +0.001(5) to +0.004(4) Å for CH₃ conjugated with CO. For CO single bonds the ranges are ?0.006(9) to +0.002(3) Å for CO conjugated with CO; and ?0.019(3) to ?0.027(9) Å for aliphatic and ether compounds. A very large and exceptional discrepancy exists for the highly strained ethylene oxide, r_s — r_e = ?0.049(5) Å and in CH₃OCH₃ and C₂H₅OCH₃ the r_s — r_e differences are ?0.029(5), ?0.040(10) and ?0.025(10) Å. Some of these discrepancies may also be due to deficiencies of the microwave substitution method caused by atomic coordinates close to inertial planes. For CN bonds, two types of NCH₃ corrections are from +0.005(6) to ?0.006(6) and from ?0.009(2) to ?0.014(6) Å; and the range for NCO is +0.012(3) to +0.028(4) Å. For isolated CC double bonds the range is + 0.025(2) to +0.028(2) Å. For conjugated CC double bonds the correction is less positive (+0.014(1) Å for benzene). For CO double bonds the corrections are ?0.004(3) to +0.003(3) Å. For bond angles of type HCH, CCH, CCC, CCO, CCO, OCO, NCO and CCC the corrections are of the order of magnitude about 1–2° (or better). Angles centered at heteroatoms are less accurate than that, when hydrogen atoms are involved. Differences in HOC and NHC angles were found in a range of ?2.3(5)° to ?6.2(4)°.     

Alkoxycarbene complexes of nickel(II)

Alkynylnickel complexes trans-C₆Cl₅Ni(PPhMe₂)₂CCR (IIIa, R  H; IIIb, R  Me; IIIc, R  Et; IIId, R  CH₂OH; IIIe, R  CH₂CH₂OH; IIIf, R  Ph; IIIg, R  C₆H₄OMe-p) have been prepared from trans-[C₆Cl₅Ni-(PPhMe₂)₂L]ClO₄ and monosubstituted acetylenes in the presence of triethylamine, and their reactions with alcohols in the presence of perchloric acid were studied. Complexes IIIa and IIIe afforded alkoxycarbene complexes trans-[C₆Cl₅Ni-(PPhMe₂)₂{C(OR′)Me}]ClO₄ (IVa, R′  Me; IVb, R′  Et; IVc, R′  n-Pr) or trans-C₆Cl₅Ni(PPhMe₂)₂{$\text{C(CH}{}_2\text{)}{}_3\text{O}$}]ClO₄(IVd), respectively, but IIIb either decomposed or afforded trans-C₆Cl₅Ni(PPhMe₂)₂CHC(OMe)Me, depending on the amount of acid used. Treatment of IVaIVd with amines resulted in deprotonation to give α-alkoxyvinyl complexes, trans-C₆Cl₅Ni(PPhMe₂)₂C(OR′)CH₂ (VIaVIc) or trans-C₆Cl₅Ni(PPhMe₂)₂$\text{CCHCH}{}_2\text{CH}{}_2\text{O}$ (VId), the reaction being reversible. A ¹H NMR study indicated: (i) that the carbene methyl and the vinyl protons IV or VI are D-exchangeable by MeOD without catalyst; (ii) that the basicity of VIa is comparable to those of amines; (iii) that the carbene complexes IVaIVc have two isomers due to hindered rotation about the C(carbene)O bond in solution, IVb existing in the Z-form in the solid state; (iv) that the rotationalbarriers (°G^≠) about the C(carbene)O bond in IVb and the NiC-(carbene) bond in IVd are 20 (or more) and 11.7 kcal/mol, respectively. These results are explained in term of double bond character of the carbene carbon and its surrounding atoms.     

Synthesis and structural characterization of the electron rich complexes Co(η-C5Me5)(R2PCH2CH2PR2) (R = Me,Ph); photoelectron spectroscopic studies of some pentamethylcyclopentadienylphosphinecobalt complexes

The compounds Co(η-C₅Me₅)(R₂PCH₂CH₂PR₂), (R = Me, Ph) have been prepared and characterized. X-Ray diffraction studies of Co(η-C₅Me₅)-(Me₂PCH₂CH₂PMe₂) show the two phosphorus atoms and the ring centroid to have a trigonal coordination around the cobalt. Photoelectron spectral studies show Co(η⁵-C₅Me₅)(R₂PCH₂CH₂PR₂) to have rather low first ionization energies of around 5.1 eV, indicating that the metal centre has a very electron rich nature.     

Synthesis and characterization of ethylxanthato complexes of zinc(II) with P-donor ligands

Monomeric, five-coordinated bis(ethylxanthato)Zn^II(phosphine) complexes [phosphine = PPh₃, P(o-tolyl)₃, P(CH₂Ph)₃] have been synthesized by addition of the phosphine ligand (1:1 molar ratio) to CH₂Cl₂ solutions of [Zn(S₂COEt)₂]. Bidentate ligands Ph₂PCH₂CH₂PPh₂ (dppe) and Ph₂P(CH₂)₄PPh₂ (dppb) reacted in a 1:2 molar ratio to form dinuclear phosphine-bridged complexes. The Zn—P bonds are very labile and are probably broken in solution. The characterization of all the compounds has been carried out by elemental analyses and spectroscopic methods (i.r. and n.m.r.). The structure of binuclear [(S₂COEt)₂Zn(-dppb)Zn(S₂COEt)₂], determined by X-ray crystallography, shows a distorted trigonal bipyramidal environment for the Zn atoms, formed by two chelating xanthate and a bridging dppb ligand.     

Permetalloplumbanes: Preparation of [Pb{Co(CO)3(L)}4] and [Pb{Fe(CO)2(NO)(L)}4].: Complexes containing four transition metal to lead bonds (L = tertiary arsine,phosphine or phosphite).

The sole and unexpected products from the reactions of a variety of lead (II) and lead (IV) compounds with [Co₂(CO)₆(L)₂] complexes (L = tertiary arsine, phosphine, or phosphite) in refluxing benzene solution are the blue, air-stable percobaltoplumbanes [Pb{Co(CO)₃(L)}₄]. These have also been obtained from the reaction of Na[Co(CO)₃(L)] (L  PBu₃ⁿ) with lead (II) acetate which with Na[Fe(CO)₂(NO)(L)] forms the isoelectronic [Pb{Fe(CO)₂(NO)(L)}₄] [L  P(OPh)₃]. The IR spectra of the complexes in the v(CO) and v(NO) regions are consistent with tetrahedral PbCo₄ or PbFe₄ fragments, trigonal bipyramidal coordination about the cobalt or iron atoms and linear PbCoAs, PbCoP, or PbFeP systems. Unlike [Pb{Co(CO)₄}₄], our complexes do not dissociate to [Co(CO)₃(L)]^? or [Fe(CO)₂(NO)(L)]^? ions when dissolved in donor solvents.