Pentacarbonyl Halides Research Articles

Reactivity of higher technetium carbonyls in CO replacement: A quantum chemical analysis

The CO replacement in higher technetium carbonyls (hexacarbonyltechntium cation, pentacarbonyltechnetium halides, and actually existing and hypothetical technetium tetracarbonyl complexes) was analyzed by quantum-chemical calculations. Dissociative and associative mechanisms of the reaction in a vacuum and in solvents were analyzed using the variational transition state theory. The solvent effect on the process was considered within the framework of PCM model and with explicit inclusion of different numbers of solvent molecules. The dissociative pathway was shown to better agree with the experimental data. Higher kinetic stability of the hexacarbonyl cation compared to pentacarbonyl halides and of pentacarbonyl halides compared to related tetracarbonyl complexes is mainly attributable to energetic features of the five-coordinate transition state (cis labilization effect exerted by π-donor ligands), as in related carbonyl complexes of other dmetals. Reactivity trends observed within the series of technetium pentacarbonyl and tetracarbonyl complexes were discussed.

Multi-step and multi-component organometallic synthesis in one pot using orthogonal mechanochemical reactions

We demonstrate that the mechanochemical strategies for oxidative addition and ligand substitution on organometallic centers can be mutually orthogonal, permitting the rational design of multi-component mechanochemical reaction procedures for assembling complex or solution-sensitive organometallic species from three, four or even five components in one pot. The herein established synthetic procedures represent a new level of complexity in mechanochemical reactions by milling and are the first to combine redox and ligand substitution reactions into mechanochemical strategies for either one-pot sequential (“telescoping”) or one-pot multi-component syntheses. This ability to combine mechanochemical transformations has enabled the solvent-free, room-temperature syntheses of relatively complex organometallics directly for simple zerovalent metal carbonyls as the simplest precursors. In particular, we demonstrate the efficiency of mechanochemical oxidative addition by targeting selected pentacarbonyl halides (fluoride, chloride, bromide, iodide) of rhenium(I) and manganese(I), and illustrate the potential of multi-step organometallic mechanochemistry in the syntheses of selected fac-tricarbonyl complexes of these metals.

Reactivity of Tc(I) tetracarbonyl complexes

Technetium tetracarbonyl complexes [TcBr(CO)4]2 and [TcXan(CO)4] (Xan is methylxanthate), being fairly stable in an inert solvent, undergo rapid decarbonylation in a donor solvent (acetonitrile). The kinetic characteristics of the reaction were determined. The experimental data and results of quantum-chemical calculations allow a conclusion that the reaction, as in the case of pentacarbonyl halides, occurs via dissociative pathway with a lower energy barrier as compared to pentacarbonyl halides. The results obtained were interpreted assuming the formation of unstable complexes of intermediate five-coordinate technetium species with an “inert” solvent molecule and the effect of this phenomenon on the relative stability of the technetium penta- and tetracarbonyl complexes. The technetium complex [TcXan(CO)4] is considerably less stable than its rhenium analog.

Crystal and molecular structure of [TcCl(CO)5] and [TcBr(CO)5]. Correlations with the reactivity and electronic structure

The crystal and molecular structures of [TcCl(CO)5] and [TcBr(CO)5] were determined. The compounds crystallize in the rhombic system, space group Pnma; a = 11.6757(18) and 11.9564(18) A, b = 11.7365(14) and 11.7250(18) A, c = 6.0407(7) and 6.2020(15) A, V = 827.77(19) and 869.5(3) A3, respectively; Z = 4. The structural data for pentacarbonyl halides were compared in the series Mn-Tc-Re and Cl-Br-I. Quantum-chemical calculations of the compounds [TcX(CO)5] (X = F, Cl, Br, I) and of the anion [TcCl3(CO)3]2− were made. A correlation between the geometry, electronic structure, and reactivity of the complexes is considered.

A solid-state 55Mn NMR spectroscopy and DFT investigation of manganese pentacarbonyl compounds

Central transition (55)Mn NMR spectra of several solid manganese pentacarbonyls acquired at magnetic field strengths of 11.75, 17.63, and 21.1 T are presented. The variety of distinct powder sample lineshapes obtained demonstrates the sensitivity of solid-state (55)Mn NMR to the local bonding environment, including the presence of crystallographically unique Mn sites, and facilitates the extraction of the Mn chemical shift anisotropies, CSAs, and the nuclear quadrupolar parameters. The compounds investigated include molecules with approximate C(4v) symmetry, LMn(CO)(5)(L = Cl, Br, I, HgMn(CO)(5), CH(3)) and several molecules of lower symmetry (L = PhCH(2), Ph(3-n)Cl(n)Sn (n= 1, 2, 3)). For these compounds, the Mn CSA values range from <100 ppm for Cl(3)SnMn(CO)(5) to 1260 ppm for ClMn(CO)(5). At 21.1 T the (55)Mn NMR lineshapes are appreciably influenced by the Mn CSA despite the presence of significant (55)Mn quadrupolar coupling constants that range from 8.0 MHz for Cl(3)SnMn(CO)(5) to 35.0 MHz for CH(3)Mn(CO)(5). The breadth of the solid-state (55)Mn NMR spectra of the pentacarbonyl halides is dominated by the CSA at all three applied magnetic fields. DFT calculations of the Mn magnetic shielding tensors reproduce the experimental trends and the magnitude of the CSA is qualitatively rationalized using a molecular orbital, MO, interpretation based on Ramsey's theory of magnetic shielding. In addition to the energy differences between symmetry-appropriate occupied and virtual MOs, the d-character of the Mn MOs is important for determining the paramagnetic shielding contribution to the principal components of the magnetic shielding tensor.

Synthesis and spectroscopic characterization of Group 15/Group 16 ligand derivatives of manganese(I) and rhenium(I) pentacarbonyl halides: influence of the Group 16 donor atom on thermodynamic and kinetic aspects of the oxidation of metal carbonyl complexes

Preparation de complexes avec les sulfures ou seleniures de phosphine ditertiaire. Etude de l'oxydation electrochimique de M(CO) 3 (dpmE)X. Potentiels d'oxydation

Sulphur–arsenic ligands. Dimethyl(methylthio)arsine complexes of halogenotrimethylplatinum(IV) and tricarbonylhalogenorhenium(I)

Dimethyl(methylthio)arsine, AsMe2(SMe)(L), is a potentially ambidentate ligand with the possibility of arsine and/or sulphur co-ordination to a transition metal. We have investigated the reaction of the ligand for the scission of the tetrameric trimethylplatinum halides, and that for carbon monoxide displacement from the rhenium pentacarbonyl halides. In both of these reactions organic arsines and sulphides individually are known to be effective, producing well characterised stable products. Ligand L reacts with [(PtXMe3)4](X = Cl, Br, or I) and with [ReX(CO)5](X = Cl, Br, or I) to yield respectively fac-[PtXMe3L2] and fac-[ReX(CO)3L2] in good yield. Hydrogen-1 and 13C n.m.r. studies demonstrate that in all complexes the ligand behaves in a monodentate manner with exclusively arsenic–metal bonds. In solution the compounds give no indications of any fluxional behaviour in the temperature range –80 to +80°C. The fac structure of all of these complexes gives rise to the interesting observation that all three methyl groups in the co-ordinated ligand AsMe2(SMe) are non-equivalent.

The structure of rhenium pentacarbonyl chloride, Re(CO)5Cl

M r= 361-7, orthorhombic, Pnma, a = 11.686(2), b= 11.661 (3), c=6.069(2)/~, V= 827.1 (6)/~3, Z=4, D x= 1.444gcm -3, 2(MoKct) = 0.7093 ,/k,/~(Mo K0t) = 8.816 cm -1, F(000) = 648.0, T = 296 K, R = 0.022 for 600 (I > 3e) reflections. The molecules are discrete monomeric units having required mirror symmetry but non-crystallographic 4mm symmetry. Important distances are: Re-Cl 2.515 (2) A; Re-C(cis to C1) 2.005 (7) and 2.031 (8) A; Re-C(trans) 1.912 (14) A. Introduction. The pentacarbonyl halides, M(CO)sX, with M = Mn, Tc and Re and X = C1, Br, I, have long been of interest for the study of bonding in metal carbonyls and their spectra have been extensively investigated (Wozniak & Sheline, 1972; Ceasar, Milazzo, Cihonski & Levenson, 1974; Hall, 1975; Wrighton, Morse, Gray & Ottesen, 1976; Behrens, 1978). In view of this it is surprising that their structures have not been studied much. Only that of MnCI(CO) 5 has been determined accurately and reported (Greene & Bryan, 1971). That of Re(CO)sI has also been determined (Russell & Ruff, 1982). In the course of some chemical studies we found ourselves with a very nicely diffracting crystal of Re(CO)sCI mounted and aligned and we considered it worth while to carry through the structure determination. Experimental. Material from reaction of

The use of core binding energies in the assignment of the ultraviolet photoelectron spectra of the manganese pentacarbonyl halides

The use of core binding energies in the assignment of the ultraviolet photoelectron spectra of the manganese pentacarbonyl halides

Paramagnetic transition-metal carbonyls and cyanides. Part 7. Electron addition to pentacarbonyl halides of chromium, molybdenum, tungsten, and rhenium induced by ionizing radiation. An electron spin resonance study

Exposure of tetra-alkylammonium salts of [Cr(CO)5I]–, [Mo(CO)5I]–, and [W(CO)5I]–, and dilute solutions of [Re(CO)5Br] and [Re(CO)5I] in methyltetrahydrofuran (mthf), to 6OCo γ-rays at 77 K gave electron-addition products characterized by large hyperfine coupling to the halogen and metal nuclei. Orbital populations for the extra electrons estimated therefrom showed trends characteristic of antibonding electrons, and in all cases the extra electron appears to be accommodated in the metal–halogen σ* orbital comprising primarily (dz2–pz). For the tungsten complex, a species exhibiting additional hyperfine coupling to a single proton was also detected. A species previously assigned the formula [Cr(CO)5I] was prepared, but gave no detectable e.s.r. spectrum.

Kinetics of Reactions of Manganese Pentacarbonyl Halides with Cyanide

The kinetics of the reactions of the manganese pentacarbonyl halides Mn(CO) 5X, X = Cl, Br, or I, with cyanide to give the [Mn(CO) 4(CN) 2] − anion are reported. The respective rate laws and rate constants indicate that the intermediate in their reaction of Mn(CO) 5Cl is Mn(CO) 5(CN), but that the intermediates in the reactions of Mn(CO) 5Br and Mn(CO) 5I are the [Mn(CO) 4 (CN)Br] − and [Mn(CO) 4(CN)I] − anions respectively.

ChemInform Abstract: PARAMAGNETIC TRANSITION METAL CARBONYLS AND CYANIDES. PART III. ELECTRON SPIN N RESONANCE STUDIES OF MANGANESE PENTACARBONYL HALIDES AFTER HIGH‐ENERGY IRRADIATION

Chemischer InformationsdienstVolume 7, Issue 45 Physical Organic Chemistry ChemInform Abstract: PARAMAGNETIC TRANSITION METAL CARBONYLS AND CYANIDES. PART III. ELECTRON SPIN N RESONANCE STUDIES OF MANGANESE PENTACARBONYL HALIDES AFTER HIGH-ENERGY IRRADIATION O. P. ANDERSON, O. P. ANDERSONSearch for more papers by this authorS. A. FIELDHOUSE, S. A. FIELDHOUSESearch for more papers by this authorC. E. FORBES, C. E. FORBESSearch for more papers by this authorM. C. R. SYMONS, M. C. R. SYMONSSearch for more papers by this author O. P. ANDERSON, O. P. ANDERSONSearch for more papers by this authorS. A. FIELDHOUSE, S. A. FIELDHOUSESearch for more papers by this authorC. E. FORBES, C. E. FORBESSearch for more papers by this authorM. C. R. SYMONS, M. C. R. SYMONSSearch for more papers by this author First published: November 9, 1976 https://doi.org/10.1002/chin.197645044AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume7, Issue45November 9, 1976 RelatedInformation

ChemInform Abstract: KINETICS OF REACTION OF RHENIUM PENTACARBONYL HALIDES WITH CYANIDE ION IN AQUEOUS METHANOL

The reactions of rhenium pentacarbonyl halides with a large excess of cyanide ion in aqueous methanolic solution follow a kinetic pattern characteristic of consecutive first-order processes [equation (i)]. Rate laws and kinetic [Re(CO)5X] [graphic omitted] [Re(CN)(CO)4X]– [graphic omitted] [RE(CN)2(CO)4]–(i) parameters are reported for these reactions, with X = Cl, Br, or I.

Paramagnetic transition-metal carbonyls and cyanides. Part III. Electron spin resonance studies of manganese pentacarbonyl halides after high-energy irradiation

Exposure of the manganese pentacarbonyl halides [Mn(CO)5X](X = Cl, Br or I), to 60Co γ-rays at 77 K gives an S=½ centre having a g ca. 2 and a large hyperfine coupling to 55Mn and the halogen nuclei. The results are interpreted in terms of electron addition into a σ* orbital involving mainly the metal dz2 and halide pz orbitals. A second centre having two apparent g values in the g= 6 region is also formed for all the three complexes. These again exhibit hyperfine coupling to 55M and to the halogen nuclei. Various structures are considered, and it is concluded that the most reasonable are cations formed by loss of an electron and one or more carbonyl groups with unpairing of the remaining electrons to give S=5//2.

Kinetics of reaction of rhenium pentacarbonyl halides with cyanide ion in aqueous methanol

The reactions of rhenium pentacarbonyl halides with a large excess of cyanide ion in aqueous methanolic solution follow a kinetic pattern characteristic of consecutive first-order processes [equation (i)]. Rate laws and kinetic [Re(CO)5X] [graphic omitted] [Re(CN)(CO)4X]– [graphic omitted] [RE(CN)2(CO)4]–(i) parameters are reported for these reactions, with X = Cl, Br, or I.

Insertion reactions of diazocyclopentadienes with halo—transition metal complexes

The reactivity of diazocyclopentadiene and diazotetraphenylcyclopentadiene, known precursors of interesting carbenes, towards some rhodium, iridium and manganese complexes has been investigated. It was found that reactions of halo-bridged-dirhodium species and manganese pentacarbonyl halides with diazocyclopentadienes at room temperature yielded halo-substituted cyclopentadienyl complexes. This reaction can be considered an insertion of the diazo species into the metal halogen bond accompanied by loss of dinitrogen. The intermediacy of free carbenes is considered unlikely.

Synthesis and characterization of 8-quinolinolato and 1,1,1-Trifiuoropentane-2,4-dionato complexes of manganese(I)

Reactions of manganese(I) pentacarbonyl halides with sodium quinolinolate (oxine) and thallium(I) 1,1,l-trifluoropentane.2,4-dionate (tfac) have afforded two new manganese(I) tetracarbonyl complexes, Mn(CO) 4(oxine) and Mn(CO) 4(tfac), respectively, as yellow-orange crystalline solids. These complexes undergo facile substitution of carbon monoxide with various monodentate ligands to yield the tricarbonyls Mn(CO) 3L(oxine) and Mn(EO) 3L (tfac) (L= C 5H 5N, 4-CH 3C 5H 4N, p-CH 3C 6H 4 NH 2 p-FC 6H 4NH 2, As(C 6H 5) 3,or P(C 6H 11 3) and the dicarbonyls Mn(CO)2L′(oxine) and Mn(CO)2 L′(tfac) (L′= P(n-C 4H 9) 3, P(C 6H 5) 3 P(OCH 3) 3, P(O-n-C 4H 9)3, or P(OC 6-H 5 3). The dicarbonyls Mn (CO) 2L′2 (oxine) can be also obtained by reaction of Mn (CO) 3(C 5H 5N)(oxine) with excess L′. At 25°C, the bidentate ligand 1,2-bis(diphenylphosphino) ethane (diphos) displaces two carbonyl groups from Mn(CO) 4, (oxine) to yield Mn (CO) 2 Mn(Co) 2(diphos)(oxine), but there is no reaction between Mn (CO) 4 (oxine) and o-phenanthroline or 2,2′-bipyridine (bipy). The complexes Mn(CO) 3(C 5H 5N 5) 2(tfac) and Mn(CO) 3 (bipy)(tfac), each containing a monodentate, carbon-bonded 1,1,1-trifluoropentane-2,4-dionato ligand, were prepared by treatment of Mn(CO) 3(C 5H 5N) 2Cl and Mn(CO) 3(bipy)Cl, respectively, with Tl(tfac). Some spectroscopic (infrared, 1H NMR, mass spectral) and chemical properties of the new complexes are presented and discussed.

Rhenium(I) complexes of (2-cyanoethyl)diphenylphosphine

Rhenium pentacarbonyl halides react with (2-cyanoethyl) diphenylphosphine (L) to yield complexes of the stoichiometry [Re(CO) 3LX] n . The infrared spectra of the complexes are consistent with structures containing terminal halogens and bridging L groups. Molecular weight studies indicate that n is two for solutions of 10 −3 M. The nitrile portion of the ligand is readily displaced by σ donor ligands to yield complexes in which L functions as a monodentate phosphine.

Single-Crystal Broad-Line 59Co and 55Mn NMR in CoMn(CO)9

The 59Co and 55Mn NMR was studied in a single crystal and solution of CoMn(CO)9. Two pairs of independent crystallographic sites were found related by the twofold axis and the mirror plane of the monoclinic crystal. The z axes of the 59Co and 55Mn electric-field-gradient tensors were found to be coaxial. The 59Co quadrupole coupling parameters were determined to be (1) e2qQ/h=129.15 MHz, η=0.1558 and (2) e2qQ/h=128.44 MHz, η=0.0937. The z component of the chemical shift was found to be identical with that for the compounds X3MCo(CO)4 (M is Si, Ge, Sn, and Pb; X is Cl, Br, I, C6H5) which have near C3ν symmetry. The 55Mn quadrupole coupling parameters were determined as (1) e2qQ/h= ∼ 20 MHz, η undetermined and (2) e2qQ/h=19.940 MHz, η=0.004. The z component of the chemical shift was found to be identical with that for the manganese pentacarbonyl halides which have approximate C4ν symmetry. The structure of CoMn(CO)9 has not been determined by x-ray crystallography as it always forms twin crystals, but the quadrupole coupling and chemical shift give evidence that there is threefold symmetry at the 59Co site and fourfold symmetry at the 55Mn site. Because the z axes of the electric-field-gradient tensors at the 55Mn and 59Co site are coaxial, they are assumed to lie along the Co–Mn bond. Information about the packing of the molecules in the crystal is therefore obtained. The bonding in CoMn(CO)9 was compared to the compounds Mn(CO)5MX3 and Co(CO)4MX3. The electrons forming the Co–Mn bond were found to be unequally shared by the two metal atoms with Co having the larger MO coefficient.

Reactions of manganese and rhenium pentacarbonyl halides with acetonitrile

Manganese and rhenium pentacarbonyl halides react with acetonitrile to give binuclear derivatives of the type [M(CO) 3X(MeCN)] 2, (X = Cl, Br, I). From Ir evidence these compounds are formulated as octahedral dimers of C 2 h symmetry with bridging halogen atoms and σ-bonded nitrile groups. The reaction between In 2(CO) 8Br 2 and acetonitrile similarly gives Mn 2(CO) 6Br 2(MeCN) 2.