Preparation of cis-Mo(CO)2(Ph2P(CH2)nPPh2)2 (n = 1, 2, 3) from cis-dicarbonylbis(norbornadiene)molybdenum and crystal structure of [cis-Mo(CO)2(Ph2P(CH2)3PPh2)2]

The complexes cis-Mo(CO)₂(Ph₂P(CH₂)_nPPh₂)₂ (n = 1, 2, 3) are synthesized by heating benzene solutions of cis-dicarbonylbis(norbornadiene)molybdenum and the corresponding diphosphines. The X-ray structural analysis of cis-Mo(CO)₂(Ph₂P(CH₂)₃PPh₂)₂ is reported, with the following crystal data: C₅₆H₅₂MoO₂P₄·2CH₂Cl₂·0.5C₆H₁₄, mol wt. 1189.81, monoclinic, space group P2₁/n, a 15.643(2), b 21.453(7), c 17.105(3) Å, β 100.75(1)°, V 5639.59 ų, Z = 4, D_c 1.39, D_m 1.36 g/cm³.     

Synthesis and structure of copper(II) trans-diaqua-bis(3-hydroxybenzoylhydrazine) nitrate dihydrate [Cu(C7H8O2N2)2(OH2)2](NO3)22H2O

Synthesis of [Cu(m-HBH)₂(OH₂)₂](NO₃)₂·2H₂O, where m-HBH = C₇H₈O₂N₂ (3-hydroxybenzoylhydrazine), is described. The structure of the compound was studied by X-ray phase analysis and IR spectroscopy; crystal data are a = 57.415(6) Å, b = 19.760(2) Å, c = 7.586(2) Å; Fdd 2, Z = 16, R(F) = 0.053. The compound consists of [Cu(m-HBH)₂(OH₂)₂]²⁺ complex cations, NO ₃ ^? anions, and two water molecules. The similarity between the IR spectra of Cu(m-HBH)₂(NO₃)₂·nH₂O and Co(m-HBH)₂(NO₃)₂·5H₂O, element analysis data, and crystal data obtained at the first stage of X-ray analysis show that the structures and compositions of these compounds are identical relative to the type of surroundings of the central atom. In contrast to the cobalt compound [Co(m-HBH)₂(OH₂)₂](NO₃)₂·3H₂O, in which the cobalt atom has a nearly regular octahedron as a coordination polyhedron, the copper(II) compound has a square bipyramid around the copper atom; c.n. is 6 = 4 + 2 (planar distances: 2.013(2) Å, 2.021(2) Å, 2.033(3) Å, 2.087(3) Å; axial distances: 2.367(3) Å, 2.374(3) Å) and lacks one crystallization water molecule.     

Crystal structure of diacetato-bis(2-methyl-2-propylamine)zinc(II)

The diacetato-bis(2-methyl-2-propylamine)zinc(II) compound crystallizes in the triclinic system, space group P-1 with unit cell parameters a = 10.0144(10)Å, b = 10.2687(10)Å, c = 10.5149(10)Å. α = 115.184(2)°, β = 97.489(2)°, γ = 114.066(2)°, ν = 830.85(14)ų. The obtained solid state structure of (^tBuNH₂)₂Zn(OOCCH₃)₂ shows both inter- and intramolecular NH—O hydrogen bond interactions which are analyzed.     

Carbon-nitrogen bond formation in the reaction of the reaction of diphenyl diazomethane Ph2 CN2 with diiron-carbene complexes (Fe2(CO)7x03BD;-C(R)C(NEt2)x03BD;-C(R)C(NEtx03BC;-C(R)C(NEt2)N(NCPh2)x03BC;-C(R)C(NEtx03BC;-C(R)C(NEt2)NN(CPh2)x03BC;-C(R)C(NEt)]

The diiron ynamine complex [Fe₂(CO)₇{μ-CR)C(NEt₂)}] (1:R=Me,2:R = C₃H₅.3:R=SiMe₃.4:R = Ph) reacts at room temperature with diphenyldiazomethane Ph₂CN₂, in hexane to yield complexes [Fe₂(CO)₆{C(R)C(NEt₂)N (NCPh₂)] (5a:R=Me,6a:R=C₃H₅.7a R=SiMe₃.8a:R=Ph) resulting from the insertion of the terminal nitrogen atom into the Fe=C carbene bond. Insertion the second nitrogen atom and formation of compounds [Fe₂(CO)₆zμ-C(R)C(NEt₂)NN(CPh₂)}] (5b:R=Me,6b:R=C₃H₅,7b:R=SiMe₃,8b:R=Ph) is observed when compounds5a-5a are treated in refluxing hexane. Transformation of compoundsa tob is also obtained at room temperature within a few days. All compounds were identified by their¹H NMR spectra. Compounds6a, 7a, 8a, and8b were characterized by single crystal X-ray diffraction analyses. Crystal data: for6a: space group = P2₁/n,a=12.853(1) A,b=24.800(7) A,c=8.947(6) A,β=99.29(3)°,Z=4, 2227 rellectionsR=0,038; for7a: space group=Pl,a=ll.483(4) A,b=14.975(4) A,c = 17.890(8) A,α = 82.80(3)°,β=94.29(7)°,γ=85.42(2),Z = 4, 5888 reflectionR = 0.035: for8a: space group = Pcab.a = 31.023(8) A.b=20.137(1) A.c=9.686(2) A.Z=8. 1651 reflections,R=0.071; for8b: space group=P2₁/n,a=21.459(4),b=10,100(3) A,c=28,439(8) A,ß=103.86(4)°,Z=8. 2431 reflections.R=0.057.     

Synthesis and characterization of thio-bis(t-butylphosphido) diiron hexacarbonyls,Fe2(CO)6(butP)2Sx (x = 2, 3). Molecular structure of Fe2(CO)6(ButPS2PBut)

Two isomers of dithio-bis(t-butylphosphido)diiron hexacarbonyl, Fe₂(CO)₆(Bu^tP)₂S₂, and trithio-bis(t-butylphosphido)diiron hexacarbonyl, Fe₂(CO)₆(Bu^tP)₂S₃ were isolated from the reaction of the lithio compound Fe₂(CO)₆(bu^tPLi)₂ with sulfur monochloride, S₂Cl₂ at − 10°C. The new complexes were characterized by IR, ¹H NMR and mass spectra and elemental analysis. The crystal and molecular structure of Fe₂(CO)₆(Bu^tPS₂PBu^t) (I) was determined by single crystal X-ray diffraction. Compound I crystallises in the orthorhombic system, space group Pna2₁ with a 2433.1(3), b 906.75(8), c 973.43(7) pm; Z = 4; d_calc 1.61 g cm⁻³; R₁ = 0.044; R₂ = 0.0515. The molecular symmetry of compound I is approximately C_2ν and the axis of the two sulfur atoms lies in the same plane which includes the two phosphorus atoms and the two PC bonds with the Bu^t groups. Reaction of the lithio compound Fe₂(CO)₆(Bu^tPLi)₂ with CH₂I₂ yielded Fe₂(CO)₆(Bu^tP)₂CH₂, along with an iron cluster of unknown structure.     

Ferromagnetic interaction between [Ni(bdt)2]− anions in [Mn2(Saloph)2(μ-OH)][Ni(bdt)2](CH3CN)2

A new molecule-based magnetic material [Mn₂(Saloph)₂(μ-OH)][Ni(bdt)₂](CH₃CN)₂ was prepared by the metathesis of [Mn(Saloph)(H₂O)(ClO₄)] (S = 2) and TBA[Ni(bdt)₂] (S = 1/2). In the crystal, [Ni(bdt)₂]^? anions form square lattices which are separated from each other by the layers of antiferromagnetically coupled binuclear cations [Mn₂(Saloph)₂(μ-OH)]⁺. The magnetic susceptibility of the material coincides with the sum of the S = 2 van Vleck dimer model and S = 1/2 Heisenberg ferromagnetic square lattice model with 2J = ?92.4 and +4.5 K, respectively. The origin of the ferromagnetic interaction can be explained by the T-shaped intermolecular overlap mode of SOMOs which spreads to the ends of [Ni(bdt)₂]^? molecules.     

Redox reaction on treating fac- or mer- [Mo(CO)3(dppm-PP')(dppm-P)] (dppm = Ph2PCH2PPh2) with Hg(SCN)2 and crystal structure of the seven-coordinate product [Mo(CO)2(NCS)2(dppm-PP')(dppm-P)]

[Mo(CO)₂(NCS)₂(dppm-PP')(dppm-P)] (dppm = Ph₂PCH₂PPh₂) is formed in a rapid and clean redox reaction when fac- or mer-[Mo(CO)₃(dppm-PP')(dppm-P)] is treated with Hg(SCN)₂: dppm-chelate ring-opening with formation of a heterobimetallic species is not observed. The X-ray crystal structure of the product shows the molecule to contain seven-coordinate Mo(II) with “cis” CO groups, both monodentate and chelating dppm ligands, and with N-bonded NCS groups. The coordination geometry is intermediate between a capped trigonal prism and a capped octahedron. Crystals of [Mo(CO)₂ (NCS)₂(dppm-PP')(dppm-P)] are orthorhombic, space group Pna2₁, with a = 21.583(7) Å, b = 12.775(4) Å, c = 18.484(5) Å, and Z = 4; the final R factor was 0.046 for 3181 observed reflections.     

Synthesis and reactions of trans-dicarbonyl bis-[1,2-bis(dimethylphosphino)ethane] vanadium(O): X-ray crystal structures of trans-V(CO)2(dmpe)2 [cis-V(CO)2(dmpe)2(CH3CN)]BPh4 and cis-V(CO)2(dmpe)2(O2CEt)

Interaction of trans-VCl₂(dmpe)₂ with sodium amalgam in tetrahydrofuran under CO gives trans-V(CO)₂(dmpe)₂. The latter is oxidized by Ag⁺ in acetonitrile to give [cis-V(CO)₂(dmpe)₂(CH₃CN)]⁺, isolated as the tetraphenylborate. Interactions with acids (HX) gives neutral complexes of the type V(CO)₂(dmpe)₂X (X = Cl, MeCO₂, EtCO₂, CF₃CO₂, PhPO₂H or NH₂SO₃); the chloride can be exchanged with N₃⁻ or CN⁻ in methanol. X-ray structural studies confirm the trans stereochemistry for V(CO)₂(dmpe)₂ and the seven-coordination of V^I in both [V(CO)₂(dmpe)₂(CH₃CN)][BPh₄] and V(CO)₂(dmpe)₂(O₂CEt), which have a pseudo octahedral geometry with the two carbonyls occupying a “split” axial site. ⁵¹V NMR and other spectra are reported.     

Crystal structures and magnetic properties of (m- or p-MPYNN)2 NiII(tdas)2

Novel Ni^II(tdas)₂ complexes, (m- or p-MPYNN)₂Ni(tdas)₂ (MPYNN=N-methylpyridinium α-nitronyl nitroxide and tdas=1,2,5-thiadiazole-3,4-dithiolate), were prepared. The Ni(tdas)₂ anions are located on the lattice points and at the lattice center in the crystal of (m-MPYNN)₂Ni(tdas)₂. The m-MPYNN cations form a centrosymmetric dimer, and the anion is sandwiched by a pair of the dimers, forming alternate stacks along the a axis. In the crystal of the (p-MPYNN)₂Ni(tdas)₂ complex, the Ni(tdas)₂ anions are located on the lattice points and at the center of the bc plane. The anion is surrounded by four p-MPYNN cations. The p-MPYNN cations also form a centrosymmetric dimer. Each cation has a short contact with a different Ni(tdas)₂ anion. The magnetic susceptibilities of both complexes decrease with decreasing temperature, indicating antiferromagnetic interaction within the radicals. The behavior of (m- and p-MPYNN)₂Ni(tdas)₂ was understood with the singlet–triplet model and the Curie–Weiss law.     

Preparation of dimethyl (R)- and (S)-2-(2-aminophenyl)-2-hydroxyethylphosphonate from anthranilic acid

An efficient synthesis of both enantiomers of dimethyl δ-amino-β-hydroxyethylphosphonate 6 has been achieved starting from anthranilic acid, through the resolution of dimethyl (±)-2-(2-N,N-dibenzylaminophenyl)-2-hydroxyethylphosphonate 9 with (S)-O-methylmandelic acid. The absolute configuration of the enantiomers 9 was assigned by the Dale and Mosher approach using the extended Newman projections and molecular mechanics.     

Lifetime of the He2(e), He2(d) and He2(f) states

Starting from the He₂(a) state absorption and induced fluorescence experiments were performed using a narrow band dye laser. The saturation intensity for the He₂(e)←He₂(a) transition yields a radiative lifetime of τ=(67±10) ns. Time resolved measurements of the laser induced fluorescence yield the radiative lifetimes for the states He₂(e): (57±10) ns, He₂(d): (25±5) ns and He₂(f): (19±5) ns. From the time integrated fluorescence data the collisional quenching rates between the above states were determined.     

Host-Guest Interactions between Calixarenes and Cp(2)NbCl(2)

The possible inclusion complexes of Cp₂NbCl₂ into calixarenes hosts have been investigated. The existence of a true inclusion complex in the solid state was confirmed by a combination of NMR, ab-initio calculations, thermogravimetric analysis, FTIR, Raman and PXRD. Ab-initio calculations, ¹H NMR solution and solid state ¹³C CP-MAS NMR results demonstrated that p-sulfonic calix[6]arene does form an inclusion complex with Cp₂NbCl₂. Raman spectroscopy showed, for the inclusion compound of p-sulfonic calix[6]arene-Cp₂NbCl₂, a band between 500 and 850 cm⁻¹ characteristic of Nb-O vibration. This result suggests that Nb(V) may engage in coordination with the oxygen of the sulfonate group, as part of the host-guest interaction. However, it is important to mention that the niobocene dichloride (Cp₂NbCl₂) dissolves in water and undergoes oxidation and hydrolysis processes to yield Cp₂NbCl₂(OH) species. For that reason this band does not exclude that the Nb-O band belongs to Cp₂NbCl₂(OH). Solid State ¹³C CP-MAS NMR and solution ¹H NMR spectroscopies together with ab-initio results showed that Cp₂NbCl₂ is included in the p-sulfonic calix[6]arene cavity, with both Cp rings inside the cavity. In contrast, the solution ¹H NMR results demonstrated that calix[6]arene does not form inclusion complex with Cp₂NbCl₂ in CDCl₃ solution. Cp₂NbCl₂ is not included in the calix[6]arene cavity, possibly due to the lack of sulfonate heads which promote Nb-O interactions and assist the inclusion of Cp₂NbCl₂ into the cavity.     

Addition of C2(CO2Me)2 to trans-MeIr(CO)(PPh3)2. Formation and isomerization of MeIr(CO)(PPh3)2[C2(CO2Me)2], and crystal structure of the thermodynamic isomer

The reaction of C₂(CO₂Me)₂ with trans-MeIr(CO)(PPh₃)₂ leads to a kinetic isomer which has been characterized by ¹H and ³¹P NMR and infrared spectra and to a thermodynamic isomer which has been characterized by ¹H and ³¹P NMR, infrared, microanalysis and X-ray crystallography. The isomerization occurs readily in solution at room temperature; somewhat more slowly at −20°C. The thermodynamically stable isomer of MeIr(CO)(PPh₃)₂[C₂(CO₂Me)₂] crystallizes in the centrosymmetric monoclinic space group P2₁/c with a 14.847(2), b 16.648(2), c 15.656(3) Å, β 90.595(14)°, V 3869.7(11) ų and Z = 4. Single-crystal X-ray diffraction data were collected with a Syntex P2₁ automated diffractometer (Mo-K_α radiation, 2θ 5–40°) and the structure was solved and refined to R_F 8.6% for all 3631 independent data (R_F 4.0% for those 2318 data with |F_o| > 6σ(|F_o|)). The Ir^I center has a trigonal-bipyramidal environment with the methyl ligand and one PPh₃ ligand occupying axial sites (Ir-Me 2.193(14), Ir-P(1) 2.425(4) Å). The C₂(CO₂Me)₂ ligand is π-bonded to the iridium atom and lies with its triple bond parallel to the equatorial coordination plane; the equatorial ligands are completed by the second PPh₃ ligand (Ir-P(2) 2.402(3) Å) and a CO ligand (Ir-CO 1.812(15) Å).     

Reactions of the Dirhenium(II) Complexes Re2 X 4(μ-dppm)2 (X=Cl, Br; dppm=Ph2PCH2PPh2) with Isocyanides. Part XV: A Fifth Structural Isomer of the [Re2Cl3(μ-dppm)2(CO)(CNXyl)2]+ Cation (Xyl = 2, 6-Dimethylphenyl)

The reaction of the unsymmetrical, coordinatively unsaturated dirhenium(II) complex [(XylNC)(OC)CIRe(μ-dppm)₂ReCl₂]O₃SCF₃ (dppm = Ph₂PCH₂PPh₂) with one equivalent of XylNC in CH₂Cl₂ affords a fifth structural isomer of the [Re₂Cl₃(μ-dppm)₂(CO)(CNXyl)₂] ⁺ cation; this is believed to have a CO-bridged structure of the type [(XylNC)ClRe(μ-Cl)(μ-CO)(μ-dppm)₂ReCl(CNXyl)]⁺. The latter complex reacts with a further equivalent of XylNC in the presence of Tl⁺ to form the [Re₂Cl₂(μ-dppm)₂(CO)(CNXyl)₃]²⁺ cation, which has been shown by IR spectroscopy, and by the X-ray crystallographic characterization of its neutral congener Re₂Cl₂(μ-dppm)₂(CO)(CNXyl)₃, to contain a very weak and unsymmetrical CO bridge.     

Unexpected formation of anti-1,2-W2(SBut)2(NMe2)4 in the thiolysis of gauche-1,2-W2Cp2(NMe2)4 and W2COT(NMe2)4 with ButSH

Thiolysis of W₂Cp₂(NMe₂)₄ and W₂COT(NMe₂)₄ with excess Bu^tSH leads to cleavage of the respective carbocyclic rings from the ditungsten center and formation of the compound anti-1,2-W₂(SBu^t)₂(NMe₂)₄ which was characterized via a single-crystal X-ray diffraction study. This product was found to be isostructural with its dimolybdenum analogue. The compound is a prototypical ethane-like dimer having a WW bond distance of 2.3011(3) Å and thiolate ligands in an anti configuration about the WW bond. The thiolysis reactions for both dimethylamide precursors are contrasted with the results of their respective alcoholysis reactions.     

Mononuclear rhenium(III) and rhenium(II) complexes of 1,2-bis(diphenylphosphino)ethylene: The structure of trans-ReCl2(dppee)2

The mononuclear rhenium(III) complexes trans-[ReX₂(dppee)₂]X · nH₂O (X = Cl or Br, dppee = Ph₂PCHCHPPh₂) have been prepared by the reaction of (n-BU₄N)₂Re₂X₈ with dppee in methanol-conc. HX; in the case of X = Cl, ethanol may also be used as the reaction solvent. These salts undergo anion exchange reactions with ClO₄⁻ and/or PF₆⁻. The rhenium(II) complex trans-ReCl₂(dppee)₂ can be prepared by the cobaltocene reduction of trans-[ReCl₂(dppee)₂]Cl · 4H₂O and the reaction of Re₂Cl₆(PBu₃)ⁿ₂ with dppee in refluxing ethanol. The spectroscopic and electrochemical properties of [ReX₂(dppee)₂]⁺ have been investigated. Cyclic voltammetry (in 0.1 M tetra-n-butyl-ammonium hexafluorophosphate-CH₂Cl₂ with a Pt-bead electrode) shows reversible redox processes at E_1/2(ox) ca +1.5 V, E_1/2(red) ca −0.2 V, and E_1/2(red) ca −1.4 V vs Ag-AGCl that correspond to the Re(IV)-Re(III), Re(III)-Re(II) and Re(I)-Re(l) couples, respectively. The single-crystal X-ray crystal structure of trans-ReCl₂(dppee)₂ has confirmed its octahedral geometry. This complex crystallizes in the monoclinic space group P2₁/c with the following unit-cell dimensions: a = 11.321(2)Å, b = 13.011(2)Å, c = 17.242(3)Å, β = 95.79(2)°, V = 2527(1)ų, and Z = 2. The structure was refined to R = 0.041 (R_w = 0.070) for 2430 data with F² > 3.0σ(F²). The ReCl and ReP distances are 2.422(2) and 2.405(2)Å, respectively.     

Crystal structure of tris(ethylenediamine)cobalt(III) (aqua)hexachloromercurate(II) chloride [Co(En)3]2[Hg2(H2O)Cl6]Cl4

The compound [Co(En)₃]₂[Hg₂(H₂O)Cl₆]Cl₄ (I, En is ethylenediamine) has been synthesized and studied by X-ray diffraction. The crystals of I (a = 21.8745(14) Å, b = 10.6008(6) Å, c=15.4465(12) Å, space group Pna2₁) consist of tris(ethylenediamine)cobalt(III) complexes (the unit cell contains two [Co(En)₃]³⁺ cations of opposite chirality). [Hg₂(H₂O)Cl₆]^2? anions, and isolated chloride ions. The complex anion consists of the tetrahedral [HgCl₄]^2? group (Hg-Cl, 2.44–2.56 Å) and the hydrated molecule [Hg(H₂O)Cl₂] (Hg-Cl, 2.301 and 2.308 Å; Hg-O, 2.788 Å) combined by weak Hg-Cl interactions (2.915 and 3.220 Å).     

Crystal structure of calcium dihydroethylenediaminetetraacetate(2-) dihydrate Ca(H2Edta)·2H2O

The crystals of Ca(H₂Edta)·2H₂O (orthorhombic system, a = 8.5919(7) Å, b = 17.807(2) Å, c = 18.941(2) Å; Z = 8, space group Pbca) precipitate from solutions of Na₂H₂Edta·2H₂O and CaCl₂. The Ca atom is surrounded by the oxygen atoms of the water molecule and the carboxyl groups of the five neighboring H₂Edta^2? anions with protonated nitrogen atoms (distorted octahedron). As a result, a three-dimensional framework of [Ca(H₂O)H₂Edta)] with built-in crystal water molecules is formed.     

Crystal structure refinement for trans-[Pd(NO3)2(H2O)2]

Single crystals of trans-[Pd(NO₃)₂(H₂O)₂] were obtained, and the crystal structure of this complex, previously obtained for polycrystals, was refined. Crystal data (BRUKER X8APEX diffractometer): a = 4.9973(7) Å, b = 10.5982(14) Å, c = 11.7008(17) Å, V = 619.70(15) ų, space group Pbca, Z = 4, d _calc = 2.856 g/cm³. The structure is composed of neutral complexes with a trans configuration. The square plane environment of the Pd atom is formed by four oxygen atoms (Pd-O(NO₃) 1.999(5) Å, Pd-O(H₂O) 2.030(5) Å) and completed to a distorted bipyramid by two intramolecular contacts (Pd…O(NO₃) 2.926 Å). The shortest hydrogen bonds are O…H 2.72 Å.