Rhenium Nitrosyl Complexes Research Articles

3.3.1. Synthesis, Spectroscopy and Structural Analysis of Technetium and Rhenium Nitrosyl Complexes

Here we report an overview of our synthetic, spectroscopic and structural studies of technetium and rhenium nitrosyl complexes. We review the results from various notes and short papers reported over the past 15 years and discuss their significance in terms of radiopharmaceutical design. A single new complex is reported, the Re I -NO complex [Re I Cl 2 (NO)(py-N(Et)-py)], in which the tridentate ligand di-(2-picolyl)(N-ethyl)amine, (py-N(Et)-py), is coordinated in a meridional manner. This complex was synthesized from the reaction of the Re I -nitrosyl complex ReCl 2 (NO)(NCMe) 3 ] and the neutral tri-amine ligand py-N(Et)-py in methylene chloride under argon. The bright red species was isolated chromatographically and recrystallized from CH 2 Cl 2 /MeOH under diethylether. A review of literature values for nitrosyl complexes with various ligands bound to the coordination site trans- to the nitrosyl group shows only minor variations in the M-N-O bond angle.

The synthesis and characterization of rhenium nitrosyl complexes. The X-ray crystal structures of [ReBr2(NO)(NCMe)3], [Re(NO)(N5)](BPh4)2] and [ReBr2(NO)(NCMe){py-CH2-NH∼CH2CH2-N(CH2-py)2}

Reactions of low oxidation state rhenium–nitrosyl complexes with polyamine ligands have been examined. Rhenium(II)–nitrosyl complexes gave an array of unstable products that were difficult to isolate cleanly. The rhenium(I)–nitrosyl complex [ReBr2(NO)(NCMe)3] gave multiple products which were more easily isolated.The major product from the reaction of [ReBr2(NO)(NCMe)3] with the potentially pentadentate ligand N1,N1,N2-tris(2-pyridinylmethyl)-1,2 ethanediamine was the dicationic species [Re(NO)(N5)]2+, which was isolated as the bis-tetraphenylborate salt. The other major product [ReBr2(NO)(NCMe){py-CH2NH∼CH2CH2N(CH2-py)2}], was separated from a number of other neutral species via chromatography. This species contains the same potentially pentadentate ligand, only here it is coordinated through only two of its amine functional groups. Left dangling is the secondary amine and both of its pyridyl groups.Both amine complexes are diamagnetic and both display their respective parent ions in the ESI(+) mass spectra. The dication [Re(NO)(N5)]2+ shows its half mass parent peak at 275 m/z while [ReBr2(NO)(NCMe){py-CH2NH∼CH2CH2N(CH2-py)2}] shows its parent peak at 751 m/z. The infrared spectrum of [ReBr2(NO)(NCMe){py-CH2NH∼CH2CH2N(CH2-py)2}] displays its ν(NO) at 1676cm−1. And the infrared spectrum of [Re(NO)(N5)](BPh4)2 displays its ν(NO) at 1714cm−1.

Rhenium Nitrosyl Complexes for Hydrogenations and Hydrosilylations

The tris(acetonitrile)dibromonitrosylrhenium(I) compound (1a) was obtained by reduction of the paramagnetic [NMe4]2[Re(NO)Br5] salt with Zn in MeCN. Subsequent reaction of 1a with THF produced the THF derivative [Re(NO)(THF)(MeCN)2Br2] (1b). Reaction of 1b with PiPr3, Pcy3, or P(p-tolyl)3 yielded bis(acetonitrile)-cis-dibromo(nitrosyl)-trans-bis(phosphine)rhenium complexes (R = iPr 2a, cy 2b, p-tolyl 2c). Treatment of 2a,b with excess NaBH4 produced the known borohydride complexes [Re(H)(η2-BH4)(NO)(PR3)2] (R = iPr 3a, cy 3b). Replacement of the BH3 moiety of 3a,b in THF by ethylene (1 bar) produced the dihydride complexes [Re(H)2(η2-C2H4)(NO)(PR3)2] (4) (R = iPr a, cy b). Protonation of 4a,b with HBF4·OEt2 afforded H2 and the monohydrido tetrafluoroborato species [Re(H)(NO)(PR3)2(η2-C2H4)(BF4)] (R = iPr 5a, cy 5b). X-ray diffraction studies were carried out on 1a, 2b,c, and 5b. Complexes 4a,b are catalytically active in olefin, imine, and ketone hydrogenations and in olefin and ketone hydrosilylations, as well as in the scrambling of H2/D2 to give HD under mild conditions.

Unprecedented ROMP Activity of Low‐Valent Rhenium–Nitrosyl Complexes: Mechanistic Evaluation of an Electrophilic Olefin Metathesis System

The reaction of [Re(H)(NO)2(PR3)2] complexes (1 a: R = PCy3; 1 b: R = PiPr3) with [H(OEt2)2][BAr(F)4] ([BAr(F)4] = tetrakis{3,5-bis(trifluoromethyl)phenyl}borate) in benzene at room temperature gave the corresponding cations [Re(NO)2(PR3)2][BAr(F)4] (2 a and 2 b). The addition of phenyldiazomethane to benzene solutions of 2 a and 2 b afforded the moderately stable cationic rhenium(I)-benzylidene-dinitrosyl-bis(trialkyl)phosphine complexes 3 a and 3 b as [BAr(F)4]- salts in good yields. The complexes 2 a and 2 b catalyze the ring-opening metathesis polymerization (ROMP) of highly strained nonfunctionalized cyclic olefins to give polymers with relatively high polydispersity indices, high molecular weights and over 80 % Z configuration of the double bonds in the chain backbone. However, these complexes do not show metathesis activity with acyclic olefins. The benzylidene derivatives 3 a and 3 b are almost inactive in ROMP catalysis with norbornene and in olefin metathesis. NMR experiments gave the first hints of the initial formation of carbene complexes from [Re(NO)2(PR3)2][BAr(F)4] (2 a and 2 b) and norbornene. In a detailed mechanistic study ESI-MS/MS measurements provided further evidence that the carbene formation is initiated by a unique reaction sequence where the cleavage of the strained olefinic bond starts with phosphine migration forming a cyclic ylide-carbene complex, capable of undergoing metathesis with alternating rhenacyclobutane formation and cycloreversion reactions ("ylide" route). However, even at an early stage the ROMP propagation route is expected to merge into an "iminate" route by attack by the ylide function on one of the N(NO) atoms followed by phosphine oxide elimination. The formation of phosphine oxide was confirmed by NMR spectroscopy. The proposed mechanism is supported further by detailed DFT calculations.

Ligand controlled dioxygen oxidation of rhenium nitrosyl complexes

The addition of an excess of phenyldiazomethane to chlorobenzene solutions of the cationic dinitrosyl bisphosphine rhenium(-I) complexes [Re(NO)2(PR3)2][BAr(F)4] (R = Cy 1a, R = (i)Pr 1b) gave the corresponding benzylidene complexes [Re{=CH(C6H5)}(NO)2(PR3)2][BAr(F)4] (2a and 2b) in good yields. The treatment of 2b with dioxygen resulted in the oxidation of one of the nitrosyl ligands into the corresponding eta2-nitrito (3b) and nitrato complexes (4b) both in the solid state and in solution. In the case of the tricyclohexylphosphine derivative 2a the analogous conversion was not observed. A mechanism for the reaction of 2b with O2 is proposed which is based on an initial SET to the O2 molecule and subsequent formation of a peroxynitrite complex followed by the formation of a dinuclear mU-N2O4 intermediate. This in turn would undergo fission of the peroxo bond to afford 3b. A related sequence of steps is anticipated for the transformation of 3b to 4b. Furthermore, a similar mechanism seems reasonable for the seemingly topochemical reaction of 2b to 3b and 4b in the solid state. The initial SET to dioxygen and subsequent formation of the peroxynitrite complex is supported by DFT calculations on the trimethylphosphine model complexes [Re=CH{C6H5})(NO)2(PMe3)2]n+ (n = 1 and 2).

The Synthesis, Crystal, Molecular and Electronic Structure of [ReCl2(NO)(py)3

In line with our investigations of rhenium nitrosyl complexes, we have studied the reaction of [ReCl3(NO)(OPPh3)(PPh3)] with pyridine. The [ReCl2(NO)(py)3] complex obtained in this reaction has been characterised by IR, electronic spectra and magnetochemical measurements; ligand field parameters and the electronic structure have been determined. The crystal and molecular structure of [ReCl2(NO)(py)3] has been solved by the heavy atom method. Crystals of [ReCl2(NO)(py)3] contain distorted octahedral molecules with the pyridine ligands in the mer-arrangement. The nitrosyl group is coordinated linearly to the rhenium atom as NO+.

New synthetic routes to some nitrosyl rhenium complexes. Crystal, molecular and electronic structure of [ReCl 3(NO)(PPh 3) 2] and [ReCl 2(CO)(NO)(PPh 3) 2] complexes

The reactions of the nitrosyl rhenium(II) complex [ReCl 3(NO)(OPPh 3)(PPh 3)] with triphenylphosphine, NaBH 4 in the presence of PPh 3, and CO in the presence of PPh 3 were examined. The rhenium nitrosyl complexes [ReCl 3(NO)(PPh 3) 2] ( 1), [ReCl 2(CO)(NO)(PPh 3) 2] ( 2) and [ReH 2(NO)(PPh 3) 3]·1/2C 6H 6 ( 3) obtained were characterised by IR, UV–Vis, NMR ( 1H and 31P) and magnetochemical measurements. For 1 and 2, the electronic, crystal and molecular structures were determined.

Preparation and reactions of half-sandwich rhenium nitrosyl complexes containing a tethered amino ligand

The aminorhenium nitrosyl complex [ η 5: η 1-C 5H 4CH 2CH 2N(CH 3) 2Re(NO)(CO)] +BF 4 − ( 5a), in which the ligating amino group was connected to the cyclopentadienyl ring, was prepared by reacting the η 5-C 5H 4CH 2CH 2N(CH 3) 2Re(NO)(CO)Br ( 4) with AgBF 4. Reaction of 5a with alkylmetal reagents provided the acyl complex η 5: η 1-C 5H 4CH 2CH 2N(CH 3) 2Re(NO)COR ( 8) (R  n-butyl, methyl, ethyl, isopropyl, benzyl). Solid state structures of 5b (X −  BPh 4 −) and the acetyl complex 8b were characterized by single-crystal X-ray analyses.

Syntheses of low-valent nitrosyl complexes of rhenium and X-ray structure of trans-[ReCl(NO)(Ph 2PCH 2CH 2PPh 2) 2][NO 3] 2 with nitrosyl derived nitrates

The nitrosyl complexes trans-[ReCl(NO)(dppe) 2]A 2 ( 1; A  BF 4 or NO 3; dppe  Ph 2PCH 2CH 2−PPh 2) and trans-[ReCl(NO)(dppe) 2][BF 4] ( 2) have been prepared from the reactions of NO[BF 4] or NO with trans-[ReCl(N 2)dppe) 2]. An unusual facile oxidation of NO to nitrate is involved in the formation of ( 1, A  NO 3), the X-ray structure of which is reported.

Nitrosyl complexes of rhenium. 3. The synthesis and substitution reactions of [ReH(CH3OH)(NO)(PPh3)3]ClO4 derived from the reaction of ReH2(NO)(PPh3)3 with HClO4. Members of the series ReHX(NO)(PPh3)3

ReH2(NO)(PPh3)3 reacts with alcoholic HClO4 to yield the solvated cation, [ReH(ROH)(NO)(PPh3)3]ClO4 (R = CH3, C2H5) which can be isolated as an explosive solid (R = CH3 only). In the solid state, the perchlorate counter ion is hydrogen bound to the ligated alcohol, as observed for [ReH(CH3OH)(CO)(NO)(PPh3)2]ClO4. This latter complex also results from the reaction of [ReH(CH3OH)(NO)(PPh3)3]ClO4 with CO under ambient conditions. On reaction with p-tolylisocyanide (RNC), however, substitution is also accompanied by dihydrogen elimination to give [Re(OR)(NO)(CNR)2(PPh3)2]ClO4, irrespective of the mole ratio of the reactants. In contrast, [ReH(CH3OH)(NO)(PPh3)3]ClO4 reacts with coordinating anions with loss of methanol to give air-sensitive ReHX(NO)(PPh3)3 (X = OCH3, F, Cl, Br, I, N3, NCO, SCN), of which only those with X = Cl, Br, N3 were characterized in solution. The compounds ReHX(NO)(PPh3)3 are similar to their osmium analogues in having a labile third phosphine. Thus, reaction with neutral ligands such as CO or RNC leads to the series of neutral rhenium hydrido nitrosyls ReHX(L)(NO)(PPh3)2. Prior to this work, the only known examples from this series were those with L = CO, X = H, F, OCH3. Interestingly, the isomer of ReHF(CO)(NO)(PPh3)2 isolated in this work differs from that previously isolated (from the reaction of [ReF(CO)(NO)(PPh3)3]+ with [Formula: see text]) in having F trans to NO. All structural assignments have been made on the basis of elemental analyses, infrared spectroscopy, 1H and 31P nmr spectroscopy and deuteration studies, where appropriate. Keywords: hydrido, nytrosyl, rhenium, complexes.

ChemInform Abstract: Nitrosyl Complexes of Rhenium. Part 2. Neutral and Cationic Monohydride Complexes of Rhenium(I) Resulting from the Reaction of ReH2(NO)(PPh3)3 with Perchloric Acid.

AbstractDas Re‐dihydrid (I) reagiert mit HClO4 in Gegenwart von CO unter Abspaltung nur eines Hydrid‐Liganden.

Nitrosyl complexes of rhenium. 2. Neutral and cationic monohydride complexes of rhenium(I) resulting from the reaction of ReH2(NO)(PPh3)3 with perchloric acid

The rhenium dihydride complex ReH/sub 2/(NO)(PPh/sub 3/)/sub 3/ reacts with HClO/sub 4/ in the presence of CO with the cleavage of only one hydride ligand. Control of the degree of acidity and the solvent system leads to isolation of compounds such as ReH(OR)(CO)(NO)(PPh/sub 3/)/sub 2/ (R = Me, Et) and (ReH(CO)(NO)(PPh/sub 3/)/sub 3/)ClO/sub 4/. The alkoxide complexes are protonated by HClO/sub 4/ to yield alcohol complexes ReH(ROH.OClO/sub 3/)(CO)(NO)(PPh/sub 3/)/sub 2/. Heating ReH(MeOH.OClO/sub 3/)(CO)(NO)(PPh/sub 3/)/sub 2/ in methanol results in the formal 1,2-elimination of dihydrogen with formation of Re(OMe)(OClO/sub 3/)(CO)(NO)(PPh/sub 3/)/sub 2/. A similar elimination reaction occurs when the alcohol complexes are reacted with halide ions to give ReX(OR)(CO)(NO(PPh/sub 3/)/sub 2/ (X = Cl, Br, I). Reacting the alcohol complexes with base or NaBH/sub 4/ however, regenerates ReH(OR)(CO)(NO)(PPh/sub 3/)/sub 2/. The perchlorate complex, Re(OMe)(OClO/sub 3/)(CO)(NO)(PPh/sub 3/)/sub 2/ reacts with NaBH/sub 4/ to give ReH/sub 2/(CO)(NO)(PPh/sub 3/)/sub 2/ via a borohydride complex. The chloro-alkoxy complexes ReCl(OR)(CO)(NO)(PPh/sub 3/)/sub 2/ also react with HClO/sub 4/ to give alcohol complexes. All structural assignments have been made on the basis of elemental analysis, infrared spectroscopy, /sup 1/H NMR spectroscopy, and deuteration studies. 14 references, 2 figures, 2 tables.

Rhenium nitrosyl complexes with simple and with sterically demanding aromatic thiolate ligands: X-ray crystal structures of [PPh4][Re2(SC6H4Me-4)7(NO)2]·CH2Cl2and [Re(SC6H3Pri2-2,6)4(NO)

Download options Please wait... Article information DOI https://doi.org/10.1039/DT9850001533 Article type Paper Download Citation J. Chem. Soc., Dalton Trans., 1985, 1533-1541 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Rhenium nitrosyl complexes with simple and with sterically demanding aromatic thiolate ligands: X-ray crystal structures of [PPh4][Re2(SC6H4Me-4)7(NO)2]·CH2Cl2 and [Re(SC6H3Pri2-2,6)4(NO)] P. J. Blower, J. R. Dilworth, J. P. Hutchinson and J. A. Zubieta, J. Chem. Soc., Dalton Trans., 1985, 1533 DOI: 10.1039/DT9850001533 To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author Philip J. Blower Jonathan R. Dilworth John P. Hutchinson Jon A. Zubieta

Nitrosyl complexes of rhenium. Synthesis of some fluoro complexes of rhenium(I), including the novel cationic complex fluorocarbonylnitrosyltris(triphenylphosphine)rhenium(I) tetrafluoroborate

Nitrosyl complexes of rhenium. Synthesis of some fluoro complexes of rhenium(I), including the novel cationic complex fluorocarbonylnitrosyltris(triphenylphosphine)rhenium(I) tetrafluoroborate

ChemInform Abstract: NITROSYL COMPLEXES OF RHENIUM. PART 3. CRYSTAL AND MOLECULAR STRUCTURE OF TETRAETHYLAMMONIUM TETRACHLORONITROSYL(PYRIDINE)RHENATE(1‐)

Chemischer InformationsdienstVolume 9, Issue 39 Physical Organic Chemistry ChemInform Abstract: NITROSYL COMPLEXES OF RHENIUM. PART 3. CRYSTAL AND MOLECULAR STRUCTURE OF TETRAETHYLAMMONIUM TETRACHLORONITROSYL(PYRIDINE)RHENATE(1-) G. CIANI, G. CIANISearch for more papers by this authorD. GIUSTO, D. GIUSTOSearch for more papers by this authorM. MANASSERO, M. MANASSEROSearch for more papers by this authorM. SANSONI, M. SANSONISearch for more papers by this author G. CIANI, G. CIANISearch for more papers by this authorD. GIUSTO, D. GIUSTOSearch for more papers by this authorM. MANASSERO, M. MANASSEROSearch for more papers by this authorM. SANSONI, M. SANSONISearch for more papers by this author First published: September 26, 1978 https://doi.org/10.1002/chin.197839071AboutPDF 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. Volume9, Issue39September 26, 1978 RelatedInformation

Nitrosyl complexes of rhenium(II). Charge distribution study of tetraethylammonium salts of penthalonitrosylrhenate(II) and of its monosubstituted derivatives

Abstract The charge distribution in [Re(NO)X 5 ] −− and [Re(NO)X 4 L] − (L = π acceptor ligand) is discussed in the light of the results from spectroscopic, spectrosmagnetic and polarographic techniques. The limits of the contributions from the different techniques and the possibility to compare the results are also considered.

Nitrosyl complexes of rhenium. Crystal and molecular structures of the tetraethylammonium salts of tetrabromo(ethanol)nitrosylrhenate-(II) and of acetonitriletetrabromonitrosylrhenate(II)

The crystal and molecular structures of the title compounds, [NEt4][Re(NO)Br4(EtOH)](I) and [NEt4][Re(NO)-Br4(MeCN)](II), have been determined by the heavy-atom method from three-dimensional X-ray data collected by counter methods. Both compounds are orthorhombic. Compound (I) crystallizes in space group Pbca, Z= 8, with cell constants a= 16.41 (2), b= 1 3.81 (1), and c= 16.91 (2)Å; compound (II) is in space group Pn21a, Z= 4, with cell constants a= 13.12(1), b= 8.71(1), and c= 17.25(2)Å. Least-squares refinements gave R 0.038 (I) and 0.030 (II), based on 837 and on 930 independent reflections. The anions display distorted octahedral geometry, with solvent molecules co-ordinated trans to nitrosyl groups. Mean Re–Br distances are 2.516 (I) and 2.511 Å(II). The nitrosyl groups are linked in an essentially linear manner, as NO+ ligands. The Re–O(EtOH)[2.161(15)Å] and Re–N(MeCN)[2.153(11)Å] distances are longer than expected for single bonds, and this together with distortions of the octahedral geometry is discussed in comparison with the structures of similar compounds.

Thermal study on some Nitrosyl Complexes of Rhenium

AbstractStudy of the thermal decomposition of (MH)2[ReCl5(NO)] where M stands for pyridine, 2,2′ dipyridyl and 1,10 phenanthroline in carbon dioxide atmosphere is described. Pyridine compound produces pyH[ReCl4py(NO)] at 250°C and [ReCl3py2(NO)] at 400°C. Dipyridyl and phenanthroline compounds produce [ReCl3(dipy)(NO)] and [ReCl3(phen)(NO)] at 210°C and 220°C respectively. The acid H[ReCl4py(NO)] decomposes under similar condition at 200°C to produce [ReCl3(NO)] and [ReCl3py2(NO)] in equivalent quantities.