Nickel Nitrosyl Complexes Research Articles

Heteroleptic nickel complexes of a bulky bis(carbene)borate ligand

Bis(carbene)borate ligand transfer to the nickel nitrosyl synthon Ni(NO)(PPh3)2Br provides the new nickel nitrosyl complex Ph2B(tBuIm)2Ni(NO)(PPh3). The solid state structure reveals a trigonal pyramidal nickel ion with a very long bond to the apical PPh3 ligand. The complex reversibly dissociates PPh3 in solution to afford three-coordinate Ph2B(tBuIm)2Ni(NO), with NMR data providing evidence for PPh3 binding at low temperatures. Ligand transfer to Ni(PMe3)2Cl2 provides the square planar complex, Ph2B(tBuIm)2Ni(PMe3)Cl, which shows no evidence for rearranging to the form a homoleptic complex with two bis(carbene)borate ligands. This complex is a suitable synthon for the [Ph2B(tBuIm)2Ni]+ fragment, as demonstrated by the synthesis of the π-allyl complex Ph2B(tBuIm)2Ni(η3-C7H7). The π-allyl complex reacts with O2 to provide benzaldehyde and an unstable complex that is tentatively identified as the nickel(II) hydroxide [Ph2B(tBuIm)2Ni(μ-OH)]2.

Cyclic gas-phase heterogeneous process in a metal-organic framework involving a nickel nitrosyl complex.

The cubic metal-organic framework MFU-4l ([Zn5Cl4(BTDD)3], H2-BTDD = bis(1H-1,2,3-triazolo[4,5-b],[4',5'-i])dibenzo[1,4]dioxin) featuring large pore apertures can be modified post-synthetically via partial or complete substitution of peripheral metal sites and chloride side-ligands, thus opening a route towards a large variety of functionalized MOFs. In this way, Ni-MFU-4l-nitrite (or Ni-MFU-4l-NO2) with an analytically determined chemical composition [Zn2.6Ni2.4(NO2)2.9Cl1.1(BTDD)3], containing accessible Ni-NO2 units, was prepared. Ni-MFU-4l-NO2 undergoes selective heterogeneous gas-phase reduction by carbon monoxide at 350 °C, leading to formation of Ni-NO units at the peripheral sites of the MFU-4l framework (Ni-MFU-4l-NO). The crystallinity and porosity of the MFU-4l framework are completely retained upon this transformation. The so-formed nickel nitrosyl complex, showing high thermal stability, readily reacts with nitrogen monoxide at room temperature, producing Ni-NO2 units and dinitrogen monoxide (N2O). Hence, the reaction of Ni-MFU-4l-NO2 with CO followed by NO represents a cyclic process with an overall stoichiometry 2NO + CO → N2O + CO2, in which the Ni-MFU-4l framework serves as a catalyst. It can be considered as a model process for the removal of highly toxic NO and CO gases, which are converted to non-toxic CO2 and N2O. Diffuse reflectance infrared Fourier transform spectroscopic studies show that at least 10 cycles can be repeated. The framework's reactivity drops down by ca. 50% after 10 cycles, which is most likely due to the accumulation of highly reactive NO2 and N2O4 contaminants. Therefore, further investigations on characterizing reaction intermediates should be done in order to improve the catalyst's performance. Our results confirm the potential of MFU-4l frameworks as selective single-site catalysts for heterogeneous gas-phase transformations and provide a motivation for further studies.

Distorted tetrahedral nickel-nitrosyl complexes: spectroscopic characterization and electronic structure.

The linear nickel-nitrosyl complex [Ni(NO)(L3)] supported by a highly hindered tridentate nitrogen-based ligand, hydrotris(3-tertiary butyl-5-isopropyl-1-pyrazolyl)borate (denoted as L3), was prepared by the reaction of the potassium salt of the ligand with the nickel-nitrosyl precursor [Ni(NO)(Br)(PPh 3 ) 2 ]. The obtained nitrosyl complexes as well as the corresponding chlorido complexes [Ni(NO)(Cl)(PPh 3 ) 2 ] and [Ni(Cl)(L3)] were characterized by X-ray crystallography and different spectroscopic methods including IR/far-IR, UV-Vis, NMR, and multi-edge X-ray absorption spectroscopy at the Ni K-, Ni L-, Cl K-, and P K-edges. For comparative electronic structure analysis we also performed DFT calculations to further elucidate the electronic structure of [Ni(NO)(L3)]. These results provide the nickel oxidation state and the character of the Ni-NO bond. The complex [Ni(NO)(L3)] is best described as [Ni (II) (NO (-) )(L3)], and the spectroscopic results indicate that the phosphane complexes have a similar [Ni (II) (NO (-) )(X)(PPh 3 ) 2 ] ground state.

Mechanistic Insights into the Formation of N2O by a Nickel Nitrosyl Complex

Reaction of [Ni(NO)(bipy)(Me2phen)][PF6] with 1 equiv of nitric oxide (NO) in CH2Cl2 results in the formation of N2O and [{(Me2phen)Ni(NO)}2(μ-η(1)-N:η(1)-O)-NO2)][PF6] (3), along with the known complex, [Ni(bipy)3][PF6]2 (4). The isolation of complex 3, which contains a nitrite ligand, demonstrates that the reaction of [Ni(NO)(bipy)(Me2phen)][PF6] with exogenous NO results in NO disproportionation and not NO reduction. Complex 3 could also be accessed by reaction of [Ni(NO)(Me2phen)][PF6] (5) with (Me2phen)Ni(NO)(NO2) (7) in good yield. Complexes 3, 5, and 7 were fully characterized, including analysis by X-ray crystallography in the case of 3 and 7. Furthermore, addition of 0.5 equiv of bipy to [Ni(NO)(bipy)][PF6] results in formation of the hyponitrite complex, [{(bipy)Ni(κ(2)-O2N2)}η(1):η(1)-N,N-{Ni(NO)(bipy)}2][PF6]2 (9), in modest yield. Importantly, the hyponitrite ligand in 9 is thought to form via coupling of two NO(-) ligands and not by coupling of a nucleophilic nitrosyl ligand (NO(-)) with an electrophilic nitrosyl ligand (NO(+)). X-ray crystallography reveals that complex 9 features a new binding mode of the cis-hyponitrite ligand.

Nitric Oxide Release from a Nickel Nitrosyl Complex Induced by One-Electron Oxidation

Reaction of [Ni(NO)(bipy)][PF6] (2) with AgPF6 or [NO][PF6] in MeCN results in formation of [Ni(bipy)x(MeCN)y](2+) and release of NO gas in moderate yields. In contrast, the addition of the inner sphere oxidant Ph2S2 to 2 does not result in denitrosylation. Instead, the diphenyldisulfide adduct [{(bipy)(NO)Ni}2(μ-S2Ph2)][PF6]2 (3) is formed in good yield. However, oxidation of 2 with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) does results in cleavage of the Ni-NO bond and generation of NO. The metal-containing product, [(bipy)Ni(η(2)-TEMPO)][PF6] (4), can be isolated as an orange-brown solid in excellent yields. In the solid state, complex 4 contains a side-on bound TEMPO(-) ligand, which is characterized by a long N-O bond length [1.383(2) Å]. The contrasting reactivity of Ph2S2 and TEMPO likely relates to their different redox potentials, as Ph2S2 is a relatively weak oxidant. Finally, the addition of pyridine-N-oxide to 2 results in the formation of the adduct, [(bipy)Ni(NO)(ONC5H5)][PF6] (5). No evidence of NO release is observed in this reaction, probably because of the low one-electron (1e(-)) reduction potential of pyridine-N-oxide.

Structure and bonding of three-coordinate N-heterocyclic carbene nickel nitrosyl complexes: Theoretical study

The structure and bonding of the for C3N3H2X2Ni(Cp)NO (X = H, F, Cl, Br) and their linkage isomers C3N3H2X2Ni(Cp)ON has been studied by carrying out density functional theory. The bonding nature of NiC bonds has been further explored by means of AIM method and natural bond orbital (NBO) analysis. Nucleus-independent chemical shift (NICS) values calculated at several points above ring center indicate aromaticity of heterocyclic cycle. Also, the effect of substitution (X = F, Cl, Br, CN) in N-heterocyclic carbene on the properties of complex has been shown.

Three-Coordinate N-Heterocyclic Carbene Nickel Nitrosyl Complexes

The N-heterocyclic carbene IPr serves as a supporting ligand in a series of low-coordinate nickel nitrosyl complexes which display a range of nitrosyl bonding modes. Attempts to form a cationic two-coordinate nickel nitrosyl led to the three-coordinate {[IPr][IPr′]Ni(NO)}+[BArF4]−, in which one of the IPr ligands exhibits unusual C(5) coordination.

Nickel nitrosyl complexes in a sulfur-rich environment: The first poly(mercaptoimidazolyl)borate derivatives

The diamagnetic nickel mononitrosyl complexes (Tm R)Ni(NO) (R = Bu t , p-Tol) and (Bm R)Ni(PPh 3)(NO) (R = Me, Bu t ) have been readily prepared from Ni(PPh 3) 2(NO)Br and the appropriate Na(Tm R) or Na(Bm R) reagents, respectively. These species constitute the first nickel nitrosyl complexes supported by these ligand systems. An X-ray diffraction study of (Tm p-Tol )Ni(NO) confirmed its pseudo-tetrahedral geometry and the presence of a nearly linear nitrosyl ligand. In contrast, (Bm Me)Ni(PPh 3)(NO) can be best described as having a trigonal pyramidal geometry, a spatial arrangement unprecedented in nickel nitrosyl chemistry, which is facilitated by the disposition of the Bm Me ligand and the presence of a weak intramolecular Ni⋯H–B interaction opposite to the apical triphenylphosphine ligand.

Synthesis and characterization of sterically hindered tris(pyrazolyl)borate Ni complexes

Addition of KTp Ph2 to a solution of NiX 2 (X = Cl, Br, NO 3, OAc and acac) or NiBr(NO)(PPh 3) 2 in THF yields the structurally characterized series [NiCl(Hpz Ph2)Tp Ph2] ( 1) and [NiXTp Ph2] (X = Br 2, NO 3, NO 3 4, OAc 5 and acac 6) including the first example of a tris(pyrazolyl)borate nickel nitrosyl complex. IR spectroscopy confirms that all the Tp Ph2 ligands are κ 3 coordinated and that the NO ligand in 3 is linearly bound. Electronic spectra are consistent with four- or five-coordinate species in solution. NMR spectroscopic studies indicate that the complexes are paramagnetic, with the exception of 3. This is confirmed by magnetic susceptibility studies, which suggest that complexes 1, 2 and 4– 6 are paramagnetic with two unpaired electrons. X-ray crystallographic studies of 5 reveal a distorted trigonal bipyramidal nickel centre with a symmetrically coordinated acetate ligand.

Tetrahedral nickel nitrosyl complexes with tripodal [N3] and [Se3] donor ancillary ligands: structural and computational evidence that a linear nitrosyl is a trivalent ligand

Linear nickel nitrosyl compounds supported by tridentate nitrogen and selenium ligands, namely the tris(3,5-dimethylpyrazolyl)hydroborato and tris(2-seleno-1-mesitylimidazolyl)hydroborato complexes, [TpMe2]NiNO and [TseMes]NiNO, have been synthesized and structurally characterized by X-ray diffraction. Computational studies demonstrate that the linear nitrosyl ligand behaves as a trivalent X3 ligand such that the Ni-N interaction has multiple bond character.

Stability and stereochemistry of tetrahedral nickel nitrosyl complexes: crystal and molecular structures of (R*,S*)-anti-[NiNCS(NO){1,2-C6H4(PMePh)2}] and (R*,S*)-anti-[NiNO{P(OMe)3][1,2-C6H4(PMePh)2}]PF6

Stability and stereochemistry of tetrahedral nickel nitrosyl complexes: crystal and molecular structures of (R*,S*)-anti-[NiNCS(NO){1,2-C6H4(PMePh)2}] and (R*,S*)-anti-[NiNO{P(OMe)3][1,2-C6H4(PMePh)2}]PF6

ChemInform Abstract: NICKEL‐NITROSYL COMPLEXES: STRUCTURE OF NITROSYLTRIS(TRIMETHYLPHOSPHINE)NICKEL HEXAFLUOROPHOSPHATE, (NI(NO)(PME3)3) PF6

Chemischer InformationsdienstVolume 15, Issue 44 Physical Organic Chemistry ChemInform Abstract: NICKEL-NITROSYL COMPLEXES: STRUCTURE OF NITROSYLTRIS(TRIMETHYLPHOSPHINE)NICKEL HEXAFLUOROPHOSPHATE, (NI(NO)(PME3)3) PF6 G. ELBAZE, G. ELBAZESearch for more papers by this authorF. DAHAN, F. DAHANSearch for more papers by this authorM. DARTIGUENAVE, M. DARTIGUENAVESearch for more papers by this authorY. DARTIGUENAVE, Y. DARTIGUENAVESearch for more papers by this author G. ELBAZE, G. ELBAZESearch for more papers by this authorF. DAHAN, F. DAHANSearch for more papers by this authorM. DARTIGUENAVE, M. DARTIGUENAVESearch for more papers by this authorY. DARTIGUENAVE, Y. DARTIGUENAVESearch for more papers by this author First published: October 30, 1984 https://doi.org/10.1002/chin.198444053AboutPDF 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 onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume15, Issue44October 30, 1984 RelatedInformation

Nickel—nitrosyl Complexes: structure of nitrosyltris(trimethylphosphine)nickel hexafluorophosphate, {Ni(NO)(PMe 3) 3} PF 6

The crystal and molecular structure of nitrosyltris-(trimethylphosphine)nickel(O) hexafluorophosphate, {Ni(NO)(PMe 3) 3}PF 6, has been determined from three dimensional single crystal X-ray analysis. The compound crystallizes in the orthorhombic space group Pnma with Z = 4 and a unit cell of dimensions: a = 16.253(3), b = 10.536(1) and c = 12.228(2) Å. The structure was solved by conventional heavy atom techniques and refined by least-squares methods to R 1 = 0.036 and R 2 = 0.048 respectively for 1085. independent reflections. The coordination geometry around the nickel is a slightly distorted tetrahedron with an average PNiP angle of 105.63° and PNiN angle 113.03°. The nickel nitrosyl group is slightly bent with an NiNO angle of 175.4(5)°. The bending occurs in the ClPlNiNO plane toward Pl. The structure is compared with other tetrahedral {MNO} 10 phosphine complexes and the MNO bonding is discussed.

Nickel nitrosyl complexes with the diphenylphosphinoethane ligand

Four-coordinate nickel nitrosyl complexes of the general formula Ni(NO)X(Dppe) (Dppe=Ph2PCH2CH2PPh2) have been prepared byin situ formation of Ni(NO2)X(Dppe), (X= Cl, Br, I or SCN) followed by reduction with triphenylphosphine, or carbon monoxide, and/or DMF. Oxygenation of the nitrosyl complexes gives the corresponding nitro products and as indicated by u.v.-vis spectroscopy involves formation of an intermediate. The oxygenation rate increases markedly in the presence of light or of a catalytic amount of benzoyl peroxide and a tentative explanation is offered for these observations. Ionic adducts are formed in reactions between the nitrosyl complexes and donor molecules.

Reactivity of nitric oxide with nickel ions in A-type zeolite

Nitric oxide adsorption over nickel-exchanged A-type zeolites has been investigated by gravimetry, e.s.r. and i.r. spectroscopy. Depending upon the nickel content of the zeolite and its dehydration process, four different nickel—nitrosyl complexes have been observed. They differ in structure as well as stability. Spin concentrations and gravimetric measurements agree well with an overall stoichiometry of one NO molecule per nickel ion in all cases.

Anionic pyrazolyl-bridged nickel nitrosyl complexes. Synthesis, structure, and reactivity

A series of anionic pyrazolyl-bridged nickel nitrosyl complexes, M+[(ON)Ni(μ-L2)(μ-X)Ni(NO)]− (where L = pyrazolyl, N2C3H3, or 3,5-dimethylpyrazolyl, N2C5H7; X = Cl, Br, I, or N2C5H7; and M = Na, (CH3)4N, or (C2H5)4N) is described. Crystallographic analyses have been carried out on two of these complexes. Crystals of [(C2H5)4N]+[(ON)Ni(μ-I)(μ- N2C5H7)2Ni(NO)]− are orthorhombic, a = 19.910(1), b = 14.0330(7), c = 9.3195(9) Å, Z = 4, space group Pn21a and crystals of [(C4H8O)2Na][(ON)Ni(μ-N2C5 H7)3Ni(NO)] are orthorhombic, a = 19.897(2), b = 19.529(3), c = 15.894(2) Å, Z = 8, space group Pbca. Both structures were solved by Patterson and Fourier syntheses and were refined by full-matrix least-squares procedures to R = 0.027 and 0.057 for 2572 and 2168 reflections with I ≥ 3σ(I) respectively. The structure of [(C2H5)4N]+[(ON)Ni(μ-I)(μ-N2C5H7)2Ni(NO)]− consists of discrete cations and binuclear anions which have approximate C2v symmetry. The nickel atoms have distorted tetrahedral coordination geometry. Important mean molecular dimensions (distances corrected for libration) are: Ni—I—Ni, 73.67(2)°, Ni—I, 2.765(3), Ni—NO, 1.649(5), Ni—N(pyrazolyl), 1.980(14) Å, and Ni—N—O, 172.5(18)°. The structure of [(C4H8O)2Na][(ON)Ni(μ-N2C5 H7)3Ni(NO)] consists of discrete ion-pair units in which the two NiNO moieties are bridged by three N2C5H7 ligands, two of which are coordinated to the sodium ion via a novel η2(N,N) π-interaction (mean Na—N = 2.61(3) Å). The sodium is also coordinated to two tetrahydrofuran oxygen atoms to give a distorted tetrahedral coordination geometry about the sodium (Na—O = 2.301(6) and 2.266(5) Å). Except for disordered tetrahydrofuran carbon atoms, the molecular unit has approximate C2v symmetry. The nickel atoms have distorted tetrahedral coordination geometry, the mean distances being Ni—NO, 1.591(6), Ni—N(pyrazolyl), 1.985(2) for the unique pyrazolyl group and 2.016(5) Å for the pyrazolyl nitrogen atoms coordinated to Na. The mean Ni—N—O angle is 176.9(11)°.

Neutral pyrazolyl-bridged nickel nitrosyl complexes. Synthesis, structure, and reactivity

A series of neutral pyrazolyl-bridged nickel nitrosyl complexes, [LNi(NO)]2 (where L = pyrazolyl, N2C3H3; 3,5-dimethylpyrazolyl, N2C5H7; or 3,5-di-tert-butylpyrazolyl, N2C11H19), is described. The nickel atoms are susceptible to nucleophilic attack and the reactivity of the dimers with neutral donor ligands is reported. In addition to the dimeric molecules a novel trimetallic nickel compound [(ON)Ni(N2C5H7)2]2Ni has also been isolated. Crystals of [Ni(NO)(N2C5H7)]2 are monoclinic, a = 18.925(2), b = 11.012(1), c = 7.037(2) Å, β = 100.93(1)°, Z = 4, space group C2/c and crystals of [(ON)Ni(N2C5H7)2]2Ni are triclinic, a = 7.4041(7), b = 9.6331(7), c = 9.7595(8) Å, α = 85.698(9), β = 73.174(8), γ = 76.109(8)°, Z = 1, space group [Formula: see text]. Both structures were solved by Patterson and Fourier syntheses and were refined by full-matrix least-squares procedures to R = 0.035 and 0.028 for 832 and 2128 reflections with I ≥ 3σ(I) respectively. Nearly planar centrosymmetric molecules of [Ni(NO)(N2C5H7)]2 contain trigonal planar nickel atoms with Ni—N(pyrazolyl) = 1.880(3) and 1.922(3), Ni—NO = 1.616(4), and N—O = 1.158(4) Å, Ni—N—O = 178.9(4)°. This structure also contains an unusually long N—N bond in the pyrazolyl ring (1.463(4) Å). Centrosymmetric molecules of [(ON)Ni(N2C5H7)2]2Ni contain a central square-planar Ni(II) atom bonded to four pyrazolyl nitrogen atoms (mean Ni—N = 1.905(1) Å) and two trigonal planar outer nickel atoms coordinated to two pyrazolyl nitrogen atoms (mean Ni—N = 1.922(3) Å) and to a somewhat bent nitrosyl group (Ni—N = 1.625(3), N—O = 1.153(4) Å, Ni—N—O = 168.9(3)°).

Reactions of Ni(NO)I with pyrazolyl gallate ligands: crystal and molecular structure of [Me2Ga(N2C5H7)(OCH2CH 2NMe2)]Ni(NO)

Ni(NO)I reacts readily with pyrazolyl gallate ligands Na+L− (where L = MeGa(N2C3H3)3, MeGa(N2C5H7)3, and [Me2Ga(N2C5H7)(OCH2CH2NMe2)]) to yield four-coordinate nickel nitrosyl complexes, LNi(NO). In addition, the compound [Me2Ga(N2-C5H7)(OCH2CH2 NMe2)]Ni(N2C5H7)2Ni(NO) has been isolated from one reaction sequence. 1H nmr data show [Me2Ga(N2C5H7)(OCH2CH2NMe2)]Ni(NO) to be stereochemically non-rigid at room temperature in solution. Crystals of [dimethyl(N,N-dimethylethanol-amino)(3,5-dimethylpyrazolyl)gallato(N(2),N(3),O)] nitrosylnickel(I) are monoclinic, a = 9.119(1), b = 13.900(2), c = 14.284(2) Å, β = 107.96(1)°, Z = 4, space group P21/c. The structure was solved by Patterson and Fourier syntheses and was refined by full-matrix leastsquares procedures to R = 0.025 and Rw = 0.032 for 1828 reflections with I ≥ 3σ(I). The coordination about the nickel atom is severely distorted tetrahedral with angles at nickel ranging from 84.4(1) to 133.5(1)°. The nitrosyl group is coordinated in a non-linear fashion with Ni—N—O = 162.3(4)°, Ni—N = 1.632(4) and N—O = 1.147(4) Å. Other important bond lengths (corrected for libration) are: Ni—O, 2.045(2), Ni—N(pyrazolyl), 1.989(3), Ni—N(amino), 2.071(3), Ga—O, 1.922(2), Ga—N, 1.998(3), and Ga—C, two at 1.971(6) Å.

Cationic nickel nitrosyl complexes with two "tripod-like" aliphatic triphosphines

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCationic nickel nitrosyl complexes with two "tripod-like" aliphatic triphosphinesDonna Berglund and Devon W. MeekCite this: Inorg. Chem. 1972, 11, 7, 1493–1496Publication Date (Print):July 1, 1972Publication History Published online1 May 2002Published inissue 1 July 1972https://doi.org/10.1021/ic50113a009RIGHTS & PERMISSIONSArticle Views128Altmetric-Citations39LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (512 KB) Get e-Alerts Get e-Alerts