Triphenyl phosphine complex of cyclopentadienyl(manganese dicarbonyl triphenyl phosphine) gold

Conclusions The triphenyl phosphine complex of cyclopentadienyl (manganese dicarbonyl triphenyl phosphine) gold was obtained.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2641–2642, November, 1973.     

Platinum and rhenium phosphine carbonyl thiolate complexes

The heterometallic complex (CO)₃(PPh₃)Re(μ-SPr)Pt(PPh₃)(CO) (I) was formed in the reaction of Re₂(μ-SPr)₂(CO)₈ with (PPh₃)₂Pt(C₂Ph₂), together with (CO)₃(PPh₃)Re(μ-SPr)₂Re(CO)₄ (II), which was also prepared by an alternative synthesis. Compounds I and II were characterized by X-ray diffraction. In I, the Re-Pt single bond, 2.7414(5) Å, is supplemented by a thiolate bridge with shortened bonds: Pt-S (2.336(2) Å) and Re-S (2.449(2) Å). The Re-P (2.469(2) Å) and Pt-P (2.329(2) Å) bonds are also shortened. Complex II resulting from replacement of one CO group in the starting rhenium complex by triphenylphosphine has no M-M bond, and the Re-S and Re-P bond lengths (2.511(2)–2.527(2) and 2.517(3) Å) are close to the length of single bonds. It is assumed that the platinum atom in I is attached to the formally double bond Re ? SPr arising upon dissociation of Re₂(μ-SPr)₂(CO)₈.     

Rapid phosphine exchange on 1.5-nm gold nanoparticles

Triphenylphosphine-cappped, 1.5-nm gold nanoparticles "Au(101)(PPh(3))(21)Cl(5)" prepared following Hutchison's procedure (Weare, W. W.; Reed, S. M.; Warner, M. G.; Hutchison, J. E. J. Am. Chem. Soc. 2000, 122, 12890) undergo rapid exchange of capping ligand phosphine with dissociated and added phosphine in dichloromethane solvent at 298 K. Remarkably, while the (1)H NMR spectrum resonances of the attached phosphine are broad, characteristic of a range of incompletely averaged environments, the (31)P NMR spectrum (observable only at 213 K and below) exhibits a single, narrow resonance indicating that all of the phosphorus atoms are magnetically equivalent.     

High-nuclearity close-packed palladium-nickel carbonyl phosphine clusters: heteropalladium

[Pd(16)Ni(4)(CO)(22)(PPh(3))(4)](2)(-) (1) and [Pd(33)Ni(9)(CO)(41)(PPh(3))(6)](4)(-) (2) were obtained as the two major products from the reduction of PdCl(2)(PPh(3))(2) with [Ni(6)(CO)(12)](2)(-). Their crystal structures as [PPh(4)](+) salts were unambiguously determined from CCD X-ray crystallographic analyses; the resulting stoichiometries were ascertained from elemental analyses. Infrared, multinuclear (1)H, (31)P[(1)H] NMR, UV-vis, CV, variable-temperature magnetic susceptibility, and ESI FT/ICR mass spectrometric measurements were performed. The Pd(16)Ni(4) core of 1 ideally conforms to a ccp nu(3) tetrahedron of pseudo-T(d)() (4 3m) symmetry. Its geometry normal to each tetrahedral Pd(7)Ni(3) face (i.e., along each of the four 3-fold axes) may be viewed as a four-layer stacking of 20 metal atoms in a ccp [a(Ni(1)) b(Pd(3)) c(Pd(6)) a(Pd(7)Ni(3))] sequence. A comparative analysis of the different ligand connectivities about the analogous metal-core geometries in 1 and the previously reported [Os(20)(CO)(40)](2)(-) has stereochemical implications pertaining to the different possible modes of carbon monoxide attachment to ccp metal(111) surfaces. The unique geometry of the Pd(33)Ni(9) core of 2, which has pseudo-D(3)(h)() (6 2m) symmetry, consists of five equilateral triangular layers that are stacked in a hcp [a(Pd(7)Ni(3)) b(Pd(6)) a(Pd(7)Ni(3)) b(Pd(6)) a(Pd(7)Ni(3))] sequence. Variable-temperature magnetic susceptibility measurements indicated both 1 and 2 to be diamagnetic over the entire temperature range from 5.0 to 300 K. Neutral Pd(12)(CO)(12)(PPh(3))(6) (3) and [Pd(29)(CO)(28)(PPh(3))(7)](2)(-) (4) as the [PPh(4)](+) salt were obtained as minor decomposition products from protonation reactions of 1 and 2, respectively, with acetic acid. Compound 3 of pseudo-D(3)(d)() (3 2/m) symmetry represents the second highly deformed hexacapped octahedral member of the previously established homopalladium family of clusters containing uncapped, monocapped, bicapped, and tetracapped Pd(6) octahedra. The unprecedented centered 28-atom polyhedron for the Pd(29) core of 4 of pseudo-C(3)(v)() (3m) symmetry may be described as a four-layer stacking of 29 metal atoms in a mixed hcp/ccp [a(Pd(1)) b(Pd(3)) a(Pd(10)) c(Pd(15))] sequence.     

Hindered axial-equatorial carbonyl exchange in an Fe(CO)(4)(PR(3)) complex of a rigid bicyclic phosphine

Variable-temperature (13)C NMR spectra for a series of Fe(CO)(4)(PR(3)) complexes ligated by phosphatri(3-methylindolyl)methane (1), phosphatri(pyrrolyl)methane (2), P(N-3-methylindolyl)(3) (3), and P(N-pyrrolyl)(3) (4) are reported. Ligand 2 was prepared by reaction of tri(pyrrolyl)methane with PCl(3) in THF and Et(3)N. Compound 2 is stable to methanolysis, hydrolysis, and aerial oxidation at room temperature. Reactions of 2 with selenium powder and Rh(acac)(CO)(2) yield phosphatri(pyrrolyl)methane selenide (5) and Rh(acac)(CO)(2) (6), respectively. The carbonyl stretching frequency in the IR spectrum of 6 and the magnitude of (1)J(Se)(-)(P) in the (31)P NMR spectrum of 5 indicate that 2 is a strong pi-acid and a weak sigma-base, commensurate with its lack of reactivity with CH(3)I. The trend in the decreasing basicity of 2 and related phosphines and phosphites was determined to be P(NMe(2))(3) > 3 > 4 > 1 > P(OPh)(3) > 2. IR data for a series of Rh(acac)(CO)(PR(3)) complexes indicate the trend in decreasing pi-acceptor ability to be 2 approximately 1 > 4 > P(OPh)(3) > 3 > PPh(3). Phosphines 1-4 were reacted with Fe(2)(CO)(9) to yield Fe(CO)(4)(1) (7), Fe(CO)(4)(2) (8), Fe(CO)(4)(3) (9), and Fe(CO)(4)(4) (10), respectively. IR data for 7-10 support the trend in pi-acidity listed above. Variable-temperature (13)C NMR spectra for compounds 8-10 show a single doublet resonance for the carbonyls in the temperature range from -80 to 20 degrees C indicative of rapid intramolecular rearrangement of carbonyls between axial and equatorial sites. However, the (13)C NMR spectrum for 7 shows slowed axial-equatorial carbonyl exchange at 20 degrees C. The limiting slow-exchange spectrum is observed at -20 degrees C. Hindered carbonyl exchange in 7 is attributed to the rigid 3-fold symmetry and steric bulk of 1. In addition to characterization of the new compounds by NMR ((1)H, (13)C, and (31)P) spectroscopy, IR spectroscopy, mass spectrometry, and elemental analysis, compounds 2, 7, 9, and 10 were further characterized by X-ray crystallography.     

A novel ring substitution reaction in a cyclopentadienylruthenium phosphine complex

The reaction between hexafluoroacetone and Ru(PPh₃)₂(π-C₅H₅)[σ-C₂(CO₂Me)₂H] affords a $\text{1}\text{1}$ adduct, containing a coordinated ester group and an intramolecular hydrogen bond; formal insertion of (CF₃)₂CO into a CH bond of the cyclopentadienyl group has also occurred.     

Catalytic cyanomethylation of carbonyl compounds and imines with highly basic phosphine

A highly basic phosphine, tris(2,4,6-trimethoxy phenyl)phosphine (TTMPP), catalyzes cyanomethylation using trimethylsilylacetonitrile (TMSCH₂CN) to give the corresponding products in good to high yields, with both carbonyl compounds and imines.     

Cationic cobalt(I) carbonyl compounds containing complexed cyclobutadienes

The first examples of cationic carbonyl complexes of cobalt-containing substituted cyclobutadiene ligands are reported. The carbon monoxide ligands in these complexes are labile, and can be displaced by benzene.     

Field-induced CO adsorption and formation of carbonyl waves on gold nanotips

We report a study of the adsorption and reaction of CO on a gold nanotip in high electrostatic fields. Field ion microscopy is used to investigate the emergence of a Au-carbonyl wave that is made visible with oxygen as the imaging gas. We set up a simple kinetic model that reproduces the adsorption wave and confirms that the presence of oxygen merely serves as an imaging gas and does not lead to field-induced oxidation of CO.     

Use of phosphine gold acetylides [(R3P)AuCCR] to form phosphine gold derivatives of tetra-iron and penta-iron clusters

Five new gold acetylides, [AuCCR], with hydroxyl or amino functions in the organic radical R have been prepared. From these, nine phosphine complexes [(R₃P)AuCCR] with R = Ph or Cy were synthesised. Reactions between the phosphine gold acetylides [(Ph₃P)AuCCC(Me)(OH)Et] or [(Cy₃P)AuCCC(Me)(OH)Et] and the iron carbonyl cluster [Et₄N][Fe₄N(CO)₁₂] gave both neutral [(R₃P)AuFe₄N(CO)₁₂] and ionic compounds [(R₃P)₂Au][Fe₄N(CO)₁₂]. Reaction with the penta-iron cluster [Et₄N][Fe₅N(CO)₁₄] afforded [(R₃P)₂Au][Fe₅N(CO)₁₄], [(R₃P)₂Au][Fe₄N(CO)₁₂] and [(R₃P)AuFe₄N(CO)₁₂]. The gold-iron clusters were characterised with spectroscopic methods (IR, NMR and Mössbauer) and in the case of [(Cy₃P)AuFe₄N(CO)₁₂] a single-crystal X-ray analysis.     

Isolable, gold carbonyl complexes supported by N-heterocyclic carbenes

Cationic gold carbonyl complexes supported by N-heterocyclic carbene ligands, SIDipp and IDipp, have been synthesized. [(SIDipp)Au(CO)][SbF(6)] has a linear, two-coordinate gold center. [(SIDipp)Au(CO)][SbF(6)] and [(IDipp)Au(CO)][SbF(6)] display ?ν(CO) values at 2197 and 2193 cm(-1), respectively. Computational studies on [(SIMe)Au(CO)](+) indicate the presence of a strong Au(I)-CO bond.     

Mixed schiff base,carbonyl(phosphine)rhenium(I) complexes

Summary The Re(CO)₂(L)P₂ complexes (L=N-methylsalicylideneiminate,N-phenylsalicylideneiminate, halfN,N-ethylenebis(salicylideneiminate) or 8-hydroxyquinolinate; P=dimethyl(phenyl)phosphine or triphenylphosphine) were synthesized from the ReCl(CO)₃P₂ complexes and characterized by elemental analysis, i.r. and¹H n.m.r. spectroscopy.     

Tertiary phosphine complexes of cyclopentadienylmolybdenum carbonyl halides. Stereoselective syntheses and isomer separations

Pure cis and trans isomers of CpMo(CO)₂(L)X (Cp = η⁵-C₅H₅, L = PPh₃ or PBu₃, X = Br, or I) have been separated by chromatography and characterized by infrared and proton NMR spectroscopy. The reactions of trans-CpMo(CO)₂(L)CH₃ with HgX₂ (X = Cl, Br, I, SCN) afford cis-CpMo(CO)₂(L)X in high yield. Both linkage isomers are obtained in the reaction with Hg(SCN)₂, L = PPh₃. The mercuric halides react with CpMo(CO)₂(L)COCH₃ to form the metalmetal bonded derivatives trans-CpMo(CO)₂(L)HgX. Reactions of CpMo(CO)₂(L)CH₃ or CpMo(CO)₂(L)COCH₃ with bromine or iodine yield the halide complexes CpMo(CO)₂(L)X (X = Br and I, respectively), the product mixtures containing high proportions of the trans isomers.     

Cationic carbonyl complexes of manganese (I) with nitriles and dinitriles

The reaction of Mn(CO)₅OClO₃ with nitriles,L, and dinitriles,L-L, in a wide variety of conditions affords cationic pentacarbonyls, [Mn(CO)₅(L)] ClO₄ and [Mn (CO)₅(L-L)] ClO₄ and fac-tricarbonyls, [Mn (CO)₃ (L)₃] ClO₄ and [(CO) ₃Mn (μ L-L) ₃Mn (CO)₃] (ClO₄)₂     

Biocompatible polymers for antibody support on gold surfaces

The elimination or minimization of non-specific protein adsorption from serum is critical for the use of surface plasmon resonance (SPR) sensors for in vitro and in vivo analysis of complex biological solutions. The ultimate goals in this application are to minimize non-specific adsorption of protein and to maximize analyte signal. A reduction of the non-specific protein adsorption from serum of up to 73% compared to carboxymethylated-dextran 500 kDa (CM-dextran) was achieved following a survey of eight biocompatible polymers and 10 molecular weights of CM-dextran. These coatings minimize non-specific adsorption on the sensor while also serving as immobilization matrices for antibody fixation to the probes. Polymers including polysaccharides: CM-dextrans, CM-hyaluronic acid, hyaluronic acid, and alginic acid were investigated. Humic acid, polylactic acid, polyacrylic acid, orthopyridyldisuldfide–polyethyleneglycol–N-hydroxysuccinimide (OPSS–PEG–NHS), and a synthesized polymer; polymethacrylic-acid-co-vinyl-acetate (PMAVA) were also used. The non-specific protein adsorption reduction was measured over a 14 day period at 0 °C for each polymer. Calibration curves using some of these polymers were constructed to show the performance and low detection limit possibilities of these new antibody supports. For many of the polymers, this is the first demonstration of employment as an antibody support for an optical or surface active sensor. CM-dextran is the polymer offering the largest signal for the antigen detection. However, the biocompatible polymers demonstrate a greater stability to non-specific binding in serum. These biocompatible polymers offer different alternatives for CM-dextran.