Polynuclear isocyanide complexes of rhenium

The arylation of carbonylgold chloride with diarylzinc compounds yields either triarylgoldzinc or diarylgoldzinc chlorides, depending on the reactant ratio and the nature of the aryl group. The same reactions with diphenylcadmium and diphenylmercury yield exclusively diphenylgoldcadmium chloride and diphenylgoldmercury chloride, respectively. The reactions of the products with N,N,N′,N′-tetramethylethylenediamine and triphenylphosphine were studied.Phenylgold has been obtained as a very unstable solid from diphenylgoldzinc chloride and diphenylgoldmercury chloride.     

Solid state structure of a rhenium bibenzimidazole complex

Re(CO)₅Br readily forms a complex with 2,2′-bibenzimidazole (bbimH₂) of the general composition (bbimH₂)Re(CO)₃Br, 1. The complex was characterized by NMR, IR, electronic and emission spectroscopy. The orange-brown compound is sparingly soluble in apolar solvents but could be crystallized from a DMF/toluene mixture. An X-ray structural investigation shows that the rhenium ion has a distorted octahedral geometry. Nitrogen atoms of the bibenzimidazole are trans to two carbonyl ligands. The secondary amine protons of the bibenzimidazole ligand form a hydrogen bond to the amide oxygen of a DMF molecule; N3–O4 2.725(7)?Å, N4–O4 2.761(7)?Å. The bending angle of the two benzimidazole units is 168°; the greatest deviation from planarity within the ligand is 0.14?Å. Crystal data: monoclinic, space group P2₁/n, a?=?10.9743(2), b?=?12.9182(2), c?=?15.1864(3)?Å, β?=?91.647(1)°, V?=?2152.06(7)?ų, T?=??90°C, Z?=?4, R ₁?=?0.025, wR ₂?=?0.062 for 4296 reflections with F _o?> 4σ(F _o) out of 4886 independent reflections.     

A complex of gold(I) benzenethiolate with isocyanide: synthesis and crystal and molecular structures

2,6-Dimethylphenyl isocyanide forms complexes with gold( I) chloride (complex 4) and gold(I) benzenethiolate (complex 5) but forms no stable complexes with gold alkanethiolates. A reaction of complex 5 with tetramethylthiuram disulfide yields gold(I) dimethyldithiocar-bamate. Stable gold(III) derivatives cannot be obtained in such a way. Shortened intermolecular Au...Au contacts in complexes 4 and 5 (X-ray diffraction) suggest the presence of “aurophilic” interactions in them.     

Homoleptic phenyl isocyanide complexes of molybdenum and tungsten: zerovalent six-coordinate versus divalent seven-coordinate

Electrochemical and chemical oxidations of Mo(CNPh)₆ and W(CNPh)₆ have been shown to yield seven-coordinate [M(CNPh)₇]²⁺. These catons, stabilized as their PF₆^? salts, can be obtained in yields of 80%. The redox and substitution chemistry of these new complexes have been explored. A convenient synthesis of W(CNPh)₆ has been devised starting from W₂(dmhp)₄ (dmhp is the anion of 2,4-dimethyl-6-hydroxypyrimidine).     

The ground-state average structure of methyl isocyanide

The use of recently determined highly precise inertial data for various isotopic modifications of methyl isocyanide has enabled the ground-state average, or r_z, structure to be determined to within very narrow limits. Harmonic corrections to ground-state rotational constants have been calculated using a high-quality, experimentally determined harmonic force field. The derived zero-point inertial constants are sufficiently accurate to enable changes in the CH bond length and NCH bond angle on deuteration to be determined. The present r_z structure determination is believed to be a physically realistic estimate of the ground-state average geometry of methyl isocyanide.     

Synthesis,structure, and photochemistry of a rhenium(I) enolate complex

The rhenium(I) enolate complex fac-(CO)₃(P(CH₃)₃)₂Re(OC(CH₃)C₅H₄) (4 was prepared from the reaction of (η⁵-C₅H₄C(O)CH₃)Re(CO)₃ (3) with P(CH₃)₃. Compound 4 was characterized structurally in the solid state by X-ray crystallography and in solution by IR and ¹H, ¹³C, and ³¹P NMR spectroscopy. Photolysis of 4 at 337 nm in CH₂Cl₂ solution cleaves the ReO bond: smooth conversionto fac-(CO)₃(P(CH₃)₃)₂ReCl (5) is observed with a quantum yield of 0.04.     

Synthesis, molecular and crystal structure of bis(triethanolamine)manganese(II) saccharinate: a seven-coordinate manganese complex with tri- and tetradentate triethanolamine ligands

The synthesis, molecular and crystal structure of bis(triethanolamine)Mn(II) saccharinate, [Mn(tea)₂](sac)₂ are reported. The configuration of the tea ligands results in an unusual example of coordination number seven for the Mn(II) ion. The two triethanolamine (tea) ligands coordinate to the Mn(II) ion forming a monocapped trigonal prism geometry, in which one of the tea ligands behaves as a tridentate ligand, while the other one acts as a tetradentate donor. The free and coordinated hydroxyl hydrogens of the tea ligands are involved in hydrogen bonding with the amine nitrogen, carbonyl and sulfonyl oxygens of the neighbouring sac ions to form a three-dimensional infinite network. A weak π–π interaction between the phenyl rings of the sac ions also occurs.     

High yield synthesis,molecular structure and n.m.r. studies of the seven-coordinate complex [WI2(CO)3(PEt3)2]

The reaction of [WI2(CO)3(NCMe)2] with two equivalents of PEt3 in Et2O/CH2Cl2 gives the MeCN-displaced product [WI2(CO)3(PEt3)2] (1) in high yield. The crystallographically determined solid state structure of (1) shows the complex to be capped octahedral with a carbonyl ligand capping an octahedral face containing the two octahedral carbonyls and one PEt3 group. The other face contains the two iodo ligands trans to carbonyl groups, and the second PEt3 ligand trans to the first PEt3 group. The low temperature (-30°C) 13C-{1H}-n.m.r. spectrum of (1) correlates with the solid state structure, and the fluxional properties of (1) have been investigated by VT 31P-{1H}-n.m.r.spectroscopy. This revised version was published online in June 2006 with corrections to the Cover Date.     

Synthesis and crystal structure of a rhenium(V) complex containing a tridentate imido-coordinated Schiff base

The complex salt trans-[Re(mps)Cl(PPh₃)₂](ReO₄) (1) (H₃mps?=?N-(2-amino-3-methylphenyl)salicylideneimine) was prepared by reaction of trans-[ReOCl₃(PPh₃)₂] with a twofold molar excess of H₃mps. The compound was characterized by spectroscopy and X-ray crystallography. The results show that the trianionic ligand mps acts as a tridentate chelate via the doubly deprotonated amino nitrogen (which is present in 1 as an imide), the neutral imino nitrogen and the deprotonated phenolic oxygen atoms. The imido nitrogen and phenolate oxygen atoms coordinate trans to each other in a distorted octahedral geometry around the rhenium(V) centre.     

A luminescent rhenium(I) complex of 2,7-dimethyl-1,8-naphthyridine: synthesis,spectroscopy and X-ray crystal structure

2,7-Dimethyl-1,8-naphthyridine (L¹) reacts with pentacarbonylchlororhenium in toluene or chloroform to give the target complex fac-{ReCl(CO)₃(L¹)}. X-ray crystallographic data were obtained for fac-{ReCl(CO)₃(L¹)}. The structural and ¹H NMR data suggest that the ligand coordinates to the rhenium in a bidentate fashion in both solid and solution states. The complex was also found to be luminescent in both solution and solid states. The fluxionality of the ligand in solution causes ligand-centred emission to be observed in solution, whereas only ³MLCT emission was observed in the solid state. Although the complex was air-stable, the lability of L¹ was studied in ¹H NMR experiments where CD₃OD induced complete ligand dissociation over the course of 24 h, and also in reaction of fac-{ReCl(CO)₃(L¹)} with one equivalent of 2,2′-bipyridine in chloroform which resulted in quantitative ligand exchange. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Simple synthesis of an allenylidene heptavalent rhenium(d0) complex

This paper reports a simple way to synthesize an allenylidene rhenium(VII) complex. The diimido adamantyl-thiolato allenylidene rhenium(VII) complex 2 was obtained through a metathetical reaction of phosphonioalkylidyne rhenium complex 1 with diphenylketene and also structurally analyzed with X-ray diffraction. Complex 2 is the first d0 allenylidene complex with structure information.     

Facile synthesis of a chiral auxiliary bearing the isocyanide group

The synthesis of a chiral isocyanide possessing the easily cleaved menthoxy group is reported. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:561–562, 2001     

Preparation and x-ray crystal structure of a seven-coordinate cobalt(II) complex with 2,6-diacetylpyridine bis(2-picolinoylhydrazone)

Summary A new seven-coordinate cobalt(II) complex has been synthesized with 2,6-diacetylpyridine bis(2-picolinoylhydrazone) (H₂dappc) and its crystal and molecular structure has been determined by x-ray diffraction methods from counter data and refined toR 0.0449 for 2128 observed reflections. The complex crystallizes in a triclinic cell, space group P¯1, with dimensions:a=13.759(8),b=7.685(3),c=13.816(7) Å, =86.50(5), =66.48(5), =85.28(5)° andZ=2. The complete structure consists of [Co(H₂dappc)(OH₂)₂] cations, chloride anions and solvating H₂O molecules, interlinked by hydrogen bonds. The geometry around the cobalt is that of a distorted pentagonal bipyramid with the H₂dappc ligand forming the equatorial plane and two H₂O molecules occupying the axial positions.     

One-pot synthesis of oxazoles using isocyanide surrogates

We wish to present herein a simple one-pot synthesis of 2,5-disubstituted oxazoles, starting from benzyl halides and acyl chlorides. The in situ formation of isocyanides, followed by the addition of an acyl chloride in the presence of a base leads to the desired oxazoles in good yields.     

Insertion and reduction chemistry of isocyanide with a cyclometalated ditantalum hydride complex

Reaction of a ditantalum hydride complex with isocyanide is reported. The hydride complex underwent single and double isocyanide insertion into Ta-H bonds, giving iminoformyl and imine-iminoacyl complexes. The transformation of the iminoformyl complex into the amido-carbyne complex was also observed.     

Characterization and alkane oxidation activity of a diastereopure seven-coordinate iron(III) alkylperoxo complex

Spectroscopic characterization and alkane oxidation studies of a diastereopure seven-coordinate high-spin iron(iii) alkylperoxo complex based on the chiral N,N',N-bis(l-prolinate)pyridine ligand Py(ProMe)(2) () are reported.     

Synthesis and molecular structure of chlorotris(trimethylsilylmethyl)trimethylsilyl-methylidyne rhenium(VII)

The complex Re(CSiMe₃)(CH₂SiMe₃)₃Cl has been isolated as yellow crystals in low yield from the reaction of ReCl₄(THF)₂ with Me₃SiCH₂MgCl and characterised by X-ray crystallography. The molecule has a trigonal bipyramidal geometry with the alkylidyne and chlorine ligands axial.     

Indazaboles—synthesis and molecular structure

The reaction of 1‐trimethylsilyl‐indazole with boranes affords indazaboles accompanied by elimination of trimethysilane. Thus, the two isomers of parent indazabole are formed in a 1:1 ratio using borane in THF (BH₃/THF), characterized by NMR spectroscopy in solution (¹H, ¹¹B and ¹³C NMR). In contrast, the analogous reaction with 1,2‐bis(tetramethylene)diborane(6) proceeds to give a single isomer of the B‐alkylated indazabole via symmetric ring cleavage of the diborane(6), as shown by NMR in solution and X‐ray structural analysis in the solid state. The molecular structure is fluxional in solution. In the solid state, the central B₂N₄ ring adopts a distorted boat conformation. Calculated gas phase geometries of the parent indazaboles and of the B‐alkylated indazabole were optimized by DFT methods at the B3LYP/6‐311 + G(d,p) level of theory. Copyright © 2010 John Wiley & Sons, Ltd.