Carbonyl Chloride Complexes Research Articles

A CuAAC Click Approach for the Introduction of Bidentate Metal Complexes to a Sulfanilamide-Derived Antibiotic Fragment.

A simple "click-chemistry" approach was employed in order to functionalize the known antibiotic fragment sulfanilamide with a bidentate pyridyl-triazole pocket, which allowed for the synthesis of ruthenium(II) and rhenium(I) carbonyl chloride complexes. Six new complexes were prepared and comprehensively characterized, including five single crystal X-ray structures, photophysical characterization, and testing for antimicrobial activity. Interestingly, functionalization of the pyridine ring with an ortho-hydroxymethyl group resulted in a greater than 100-fold increase in the rate of ligand release in a dimethylsulfoxide solution. Subsequent studies indicated this process could be further accelerated by irradiation with 265 nm light. Structural characterization of four of the complexes indicates that this is the result of a lengthening and weakening of the Re-NPyridine bond (average (Ltri) = 2.19 Å vs LtriOH = 2.25 Å) due to the steric influence of the hydroxymethyl group. The organometallic rhenium(I) pyridyl-triazole functionality maintains its characteristic fluorescent properties despite the presence of the sulfonamide moiety. Two of the compounds showed modest antimicrobial activity against methicillin-resistant Staphylococcus aureus, whereas the structurally similar sulfamethoxazole alone showed no activity under the same conditions.

Synthesis and Characterization of Novel Re(BIAN)(CO)3Cl Derivatives Including the First Example of a Water-soluble Tricarbonyl Rhenium(I) Complex with Bis(imino)acenaphthene Ligands

A series of rhenium(I) carbonyl chloride complexes carrying bis(imino)acenaphthene (BIAN) molecules as p-acceptor ligands was prepared and characterized by various spectroscopic techniques. Among the novel compounds described, the remarkable example of a deeply colored water-soluble rhenium carbonyl derivative is presented. The crystal structures of this family of BIAN compounds are also reported, which confirm the position of the chloro ligand at the tricarbonyl rhenium(I) center. In the case of BIAN ligands carrying bulky substituents in the ortho-position of the arylimino subunits, evidence has been found for an exchange of the halide ligand in solution, which is considered to be of major relevance for catalytic applications. Implications of our results for the fields of photocatalytic CO2 reduction and the controlled release of the gasotransmitter CO in aqueous solution are briefly discussed.

Immobilization of atmospheric nitrogen by lower palladium carbonyl complexes

It has been experimentally shown that the action of nitrogen onto hydrochloric acid solutions containing carbonylchloride complexes of palladium in lower oxidation states at room temperature and atmospheric pressure leads to its immobilization with the formation of ammonia. Some elements of the possible mechanism of the immobilization of nitrogen have been discussed.

Complexes of Ir(III)-octaethylporphyrin with peptides as probes for sensing cellular O2.

IrIII–porphyrins are a relatively new group of phosphorescent dyes that have potential for oxygen sensing and labeling of biomolecules. The requirement of two axial ligands for the IrIII ion permits simple linkage of biomolecules by a one-step ligand-exchange reaction, for example, using precursor carbonyl chloride complexes and peptides containing histidine residue(s). Using this approach, we produced three complexes of IrIII–octaethylporphyrin with cell-penetrating (Ir1 and Ir2) and tumor-targeting (Ir3) peptides and studied their photophysical properties. All of the complexes were stable and possessed bright, long-decay (unquenched lifetimes exceeding 45 μs) phosphorescence at around 650 nm, with moderate sensitivity to oxygen. The Ir1 and Ir2 complexes showed positive staining of a number of mammalian cell types, thus demonstrating localization similar to endoplasmic reticulum and ATP- and temperature-independent intracellular accumulation (direct translocation mechanism). Their low photo- and cytotoxicity allows intracellular oxygen to be probed.

Ruthenium(II) carbonyl chloride complexes containing pyridine-functionalised bidentate N-heterocyclic carbenes: Synthesis, structures, and impact of the carbene ligands on catalytic activities

A series of new ruthenium(II) carbonyl chloride complexes with pyridine-functionalised N-heterocyclic carbenes [Ru(Py-NHC)(CO) 2Cl 2], [Py-NHC = 3-methyl-1-(2-pyridyl)imidazol-2-ylidene, 1 ( 1a and 1b); 3-methyl-1-(2-picoyl)imidazol-2-ylidene, 2 ( 2a and 2b); 3-methyl-1-(2-pyridyl)benzimidazolin-2-ylidene, 3 ( 3b); 3-methyl-1-(2-picoyl)benzimidazolin-2-ylidene, 4 ( 4a and 4b); 1-methyl-4-(2-pyridyl)-1,2,4-triazoline-5-ylidene, 5 ( 5a and 5b)] have been prepared by transmetallation from the corresponding silver carbene complexes and characterized by NMR, IR spectroscopy and elemental analysis. In these complexes with bidentate Py-NHC ligands, one CO ligand is trans to the Py ligand. In 1a, 2a, 4a, and 5a, the NHC ligand is trans to the other CO ligand, thus leaving the two Cl − ligands trans to each other. In 1b, 2b, 3b, 4b, and 5b, the NHC ligands are trans to one Cl − ligand, and the two Cl − ligands are cis to each other. The structures for 1b, 2b, 3b and 4b have been determined by single-crystal X-ray diffraction. These complexes are efficient catalysts in the transfer hydrogenation of acetophenone and their catalytic activities are found to be influenced by electronic effect of the N-heterocyclic carbene ligands.

Electrogenerated chemiluminescence from osmium(II) polypyridine carbonyl chloride systems

The spectroscopy, electrochemistry and electrogenerated chemiluminescence (ECL) of four osmium(II) phenanthroline carbonyl chloride complexes are reported. Three of these compounds also contain diphosphine chelating ligands. ECL is generated in acetonitrile solutions with tri- n-propylamine (TPrA) as an oxidative–reductive coreactant. ECL efficiencies ( ϕ ecl = photons emitted per redox event) between 0.011 and 0.13 were obtained in air saturated and deoxygenated solutions with Ru(bpy) 3 2+ (bpy = 2,2′-bipyridine) as a relative standard ( ϕ ecl = 1). The ECL intensity peaks at a potential corresponding to oxidation of both TPrA and the osmium systems, while ECL spectra (obtained using absorption filters) are similar to photoluminescence spectra, indicating that emission is from the excited states of the osmium complexes.

Synthesis, structure and catalytic activities for the hydrogen transfer reactions of the ruthenium(II) carbonyl chloride complexes with pyridine-2,6-diimine

Abstract Two Ru(II) carbonyl chloride complexes with pyridine-2,6-diimine, (L)Ru(CO)Cl2 (L = 2,6-diacetylpyridinebis(2,4,6-trimethylanil), 1; L = 2,6-diacetylpyridinebis(2,6-diisopropylanil), 2) have been synthesized and characterized. The structure of compound 1 has been determined by X-ray crystallography, which show the distorted octahedral geometry around Ru(II). Complexes 1 and 2 have been proved to be active in the transfer hydrogenation of acetophenone by propan-2-ol.

Synthesis, structures and catalytic activities of ruthenium(ii) carbonyl chloride complexes containing pyridine-functionalised N-heterocyclic carbenes

A series of ruthenium(II) carbonyl chloride complexes with pyridine-functionalised N-heterocyclic carbenes, trans(Cl)- and cis(Cl)-[Ru(Py-NHC)(CO)2Cl2] [Py-NHC = 3-tert-butyl-1-(2-pyridyl)imidazol-2-ylidene, 1a and 1b; 3-n-butyl-1-(2-pyridyl)imidazol-2-ylidene, 2a and 2b; 3-tert-butyl-1-picolylimidazol-2-ylidene, 3a and 3b; 3-n-butyl-1-picolylimidazol-2-ylidene, 4a and 4b; 3-benzyl-1-picolylimidazol-2-ylidene, 5a and 5b] have been prepared by transmetallation from the corresponding silver carbene complexes and characterised by elemental analyses, infrared and 1H and 13C NMR spectroscopies. The yields of trans(Cl)- and cis(Cl)-isomers could be controlled by altering the reaction conditions: the trans-isomers were kinetically formed as the main products in 60-70% yield in CH2Cl2 at ambient temperature while the thermodynamic cis-isomers were obtained as the major products in 70-80% yield in toluene at refluxing temperature. The trans-isomer was transformed into the thermodynamic cis-isomer by heating in CH2Cl2 in a Teflon-lined stainless autoclave for 24 h at 120 degrees C. The molecular structures of 1a, 1b, 2b, and 4b have been determined by single-crystal X-ray diffraction. These complexes showed catalytic activities in hydrogen transfer reactions of ketones.

Iron Complexes Containing the Tripodal Tetraphosphine Ligand P(CH(2)CH(2)PMe(2))(3).

The preparation and characterization of iron(II) complexes containing the tripodal tetraphosphine ligand tris[2-(dimethylphosphino)ethyl]phosphine, P(CH(2)CH(2)PMe(2))(3) (PP(3), 1), are reported. The complex FeCl(2)(PP(3)) (2) was formed by the reaction of PP(3) with anhydrous iron(II) chloride. The complexes FeHCl(PP(3)) (3) and FeH(2)(PP(3)) (4) were formed by the reaction of 2 with lithium aluminum hydride. Likewise, the complexes FeMeCl(PP(3)) (5) and FeMe(2)(PP(3)) (6) were formed by the reaction of 2 with methyllithium or dimethylmagnesium. Reaction of 2 with CO afforded a mixture of isomeric carbonyl chloride complexes [Fe(CO)Cl(PP(3))](+) (7 and 8). Reaction of 2 with PPh(3) afforded [Fe(PPh(3))Cl(PP(3))](+) (9). The air-sensitive complexes 2-9 were characterized by multinuclear NMR spectroscopy, and 9 was characterized by X-ray crystallography. Crystals of 9 (BPh(4) salt), C(54)H(65)BClFeP(5), M 971.09, are monoclinic, space group P2(1)/c, a = 13.246(3) Å, b = 30.314(2) Å, c = 14.338(2) Å, beta = 100.92(2) degrees, Z = 4; R = 0.058.

Di- and tri-nuclear osmium carbonyl chloride complexes: x-ray structures of Os2(CO)8Cl2 and Os3(CO)12Cl2

Os2(CO)8Cl2(1) is orthorhombic P212121 witha=9.3599(9),b=9.879(2),c=16.014(3)A, V=1480A3, Dc=3.03 Mgm−3 for Z=4. Structure solved by Patterson methods. Final R=0.038, Rw=0.038 [w=(σ2F)] for 1270 observed reflections and 141 parameters. Os3(CO)12Cl2(2) is monoclinic C2/m witha=12.105(3), b=10.612(3),c=8.798(1) A, β=117.02(2)°, V=1006A3, Dc=3.22 Mgm−3 for Z=2. Structure solved by Patterson methods. Final R=0.036, Rw=0.037 (w=(σ2F)−) for 821 observed reflections and 75 parameters.

Synthesis of Ruthenium(II) Carbonyl Chloride Complexes Containing N-Donor Bidentate Ligands

Abstract A series of new Ru(CO)2Cl2L compounds (L=bidentate N-donor ligand) have been prepared by the reaction of [Ru(CO)2Cl2]n with L in methanol. The complexes have been characterized by elemental analysis, conductivity measurements and spectroscopic data and have trans-chlorines and cis-carbonyl ligands.

Dependence of iridium Mössbauer isomer shifts on oxidation state: an inversion for low valent carbonyl complexes

The 193Ir Mössbauer isomer shifts of a set of closely related iridium carbonyl chloride complexes with oxidation states +1, +1.1, +1.4, and +2 have been found to decrease with increasing oxidation state. This is the inverse of the normal trend due to decreased shielding of the s electrons from the nuclear charge by removal of d electrons, and is attributed to the combined effect of strong π-backbonding and 6s character in the nominally 5d electrons removed in changing the oxidation state. An inverted isomer shift-oxidation state dependence is predicted for d m ( m > 7) metal complexes with strong π-acceptor ligands.