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Start Over Author "Manassero, M" Publisher royal society of chemistry
16 results on '"Manassero, M"'

1. Reactivity of nitrido-carbonyl clusters: synthesis and solid state structure of [Fe5MnN(CO)(16)](2-) and [Fe6N(CO)(14)NO](2-); oxidation of a cluster-coordinated nitride

Author

DELLA PERGOLA, R, Garlaschelli, L, Manassero, M, Sansoni, M, Strumolo, D, de Biani, F, Zanello, P, DELLA PERGOLA, ROBERTO, Zanello, P., DELLA PERGOLA, R, Garlaschelli, L, Manassero, M, Sansoni, M, Strumolo, D, de Biani, F, Zanello, P, DELLA PERGOLA, ROBERTO, and Zanello, P.

Abstract

The cluster [Fe5MnN(CO)16]2 (1) was synthesized from [Fe6N(CO)15]3- and Mn2(CO)10, in refluxing EtCN, or [Fe4N(CO)12]- and [FeMn(CO)9] -. Its solid state structure was determined on the [Me3NCH2Ph] + salt, and consists of an octahedral metal cage, enclosing a six-coordinated nitrido ligand. The position of the manganese atom in the solid state could be established, despite some crystallographic disorder, by considering the local stereochemistry of the ligands. The cluster [Fe6N(CO)14NO]2- (2) was obtained in moderate yields by the reaction of [Fe4N(CO12] with Mo(CO)3(EtCN)3. The nitrosyl is formed by oxidation of the starting nitride, and the source of the oxygen is presumably a carbonyl, whose splitting is mediated by the molybdenum complex. This process is the first example of an oxidation of a nitride in a carbonyl cluster. The solid state structure of the iron cluster is also octahedral, and the linear nitrosyl ligand was unambiguously located from the short Fe–N bond distance, and from dishomogeneous distribution of ligands. Cyclic voltammetric studies have shown that electron transfer processes are followed by chemical reactions thus testifying that no stable redox congeners exist for these two nitride clusters.

Published
2001

2. Iron Iridium Mixed-Metal Carbonyl Clusters .2. Synthesis and Chemical Behavior of the Tetranuclear complexes [FEIR3(CO)12]-, [FE2IR2(CO)12]2-, [FE2IR2H(CO)12]-, and [FE3IR(CO)13]-. Solid-State Structures of [N(PPH3)2][FEIR3(CO)12], [NET4]2[FE2IR2(CO)12], and [PPH4][FE2IR2(CO)12-(MU-3-AU(PPH3))]

Author

DELLA PERGOLA, R, Garlaschelli, L, Demartin, F, Manassero, M, Masciocchi, N, Sansoni, M, DELLA PERGOLA, ROBERTO, Sansoni, M., DELLA PERGOLA, R, Garlaschelli, L, Demartin, F, Manassero, M, Masciocchi, N, Sansoni, M, DELLA PERGOLA, ROBERTO, and Sansoni, M.

Abstract

The compound [Felr3(CO)12]- can be obtained by degradation of [Felr4(C0)l5]2- under a carbon monoxide atmosphere as well as by reduction of an equimolar mixture of [Fe(CO)5] and [Ir4(CO)12] in alcoholic NaOH under 1 atm of carbon monoxide. The molecular structure of the anion consists of a tetrahedron of metal atoms surrounded by twelve carbonyl groups: nine are terminally bound whereas three are bridging the edges of the Felr2 basal face. The dianion [Fe2lr2(C0)l2]2- was obtained by several different ways, the most selective being the condensation of [Fe2(CO)9] with [Ir(CO)4]-. The molecular structure of the dianion is based on a tetrahedral cluster of metal atoms and consists of an apical Ir(CO)3 group co-ordinated by three metal-metal bonds to a basal Fe2lr(CO)9 fragment containing two Fe(CO)2 units and one Ir(CO)2 group linked to each other by a metal-metal bond and bridging carbonyl groups.The salt [PPh4]2[Fe2lr2(CO)12] reacts with [Au(PPh3)CI] to give [PPh4][Fe2lr2(CO)12{m3-Au(PPh3)}]. The metal framework of the anion is a trigonal bipyramid with the Au(PPh3) moiety in one of the apical positions, the other being occupied by a Fe(CO)3 group. Each edge of the equatorial triangle, formed by one iron and two iridium atoms, is spanned by a bridging carbonyl ligand, and two terminal CO groups are attached to each metal of this triangle.

Published
1990

3. Synthesis and Characterization of Pentanuclear Fe-Ir Carbonyl Clusters: Solid-State Structures of [N(PPH3)2]2[FEIR4(CO)15] and [PPH4][FE2IR3(CO)14]

Author

DELLA PERGOLA, R, Garlaschelli, L, Demartin, F, Manassero, M, Masciocchi, N, Sansoni, M, Fumagalli, A, DELLA PERGOLA, ROBERTO, Fumagalli, A., DELLA PERGOLA, R, Garlaschelli, L, Demartin, F, Manassero, M, Masciocchi, N, Sansoni, M, Fumagalli, A, DELLA PERGOLA, ROBERTO, and Fumagalli, A.

Abstract

The dianion [Felr4( C0)15]2- can be obtained by reduction of an equimolar mixture of [Fe(CO)4] and [Ir4(CO)12] in alcoholic NaOH and under 1 atm of carbon monoxide. Its metal framework consists of a trigonal bipyramid with the equatorial triangle formed by iridium atoms. The monoanion [Fe2lr3(CO)14]- was obtained from [Fe(C0)4]2- and [lr(CO)2Cl2]-. Its metallic framework is comprised of an iridium triangle capped on opposite sides by two iron atoms. In the derivative (1) the trigonal bipyramid is considerably elongated in the direction of the apical atoms, when compared with that in (2). This elongation is consistent with the increased number of cluster valence electrons: 76 in (1) and 72 in (2).

Published
1989

4. Synthesis and Chemical Characterization of the Hexanuclear Anions [IR6(CO)14X]- (X=CL, BR, I, OR SCN): Crystal and Molecular-Structures of [PPH4][IR6(MU-CO)2(CO)12(MU-BR)] and [N(PPH3)2][IR6(MU-CO)2(CO)12(MU-X)] (X=I OR SCN)

Author

DELLA PERGOLA, R, Garlaschelli, L, Martinengo, S, Demartin, F, Manassero, M, Masciocchi, N, DELLA PERGOLA, ROBERTO, Masciocchi, N., DELLA PERGOLA, R, Garlaschelli, L, Martinengo, S, Demartin, F, Manassero, M, Masciocchi, N, DELLA PERGOLA, ROBERTO, and Masciocchi, N.

Abstract

The salts of the monosubstituted hexanuclear anions [Ir6(CO)14X]- [X = Cl (1,)Br (2), I (3), or SCN (4)] have been prepared by treating [Ir6(CO)16] with halides or pseudohalides at room temperature in tetrahydrofuran solution. The three anions consist of slightly distorted octahedra of iridium atoms bearing twelve terminal and two edge bridging carbon monoxide groups. In all cases the halogen atoms or the pseudohalogen group adopt a bridging co-ordination on an Ir-lr edge.

Published
1988

8. Synthesis and Characterization of Pentanuclear Fe-Ir Carbonyl Clusters: Solid-State Structures of [N(PPH3)2]2[FEIR4(CO)15] and [PPH4][FE2IR3(CO)14]

Author

Alessandro Fumagalli, Norberto Masciocchi, Mario Manassero, Mirella Sansoni, Roerto Dalla Pergola, Francesco Demartin, Luigi Garlaschelli, DELLA PERGOLA, R, Garlaschelli, L, Demartin, F, Manassero, M, Masciocchi, N, Sansoni, M, and Fumagalli, A

Subjects
CHIM/03 - CHIMICA GENERALE E INORGANICA, Stereochemistry, mixed-metal, chemistry.chemical_element, General Chemistry, Triclinic crystal system, iridium, carbonyl cluster, heterometallic cluster, electron counting, Metal, Crystallography, chemistry.chemical_compound, Trigonal bipyramidal molecular geometry, iron, chemistry, visual_art, Cluster (physics), visual_art.visual_art_medium, Iridium, Valence electron, Derivative (chemistry), Carbon monoxide
Abstract

The dianion [FeIr4(CO)15]2– can be obtained by reduction of an equimolar mixture of [Fe(CO)5] and [Ir4(CO)12] in alcoholic NaOH and under 1 atm of carbon monoxide. The salt [N(PPh3)2]2[FeIr4(CO)15](1) crystallizes in the triclinic space group P with unit-cell dimensions a= 11.399(3), b= 14.032(3), c= 29.163(4)A, α= 86.18(2), β= 84.52(2), γ= 80.14(2)°, and Z= 2. Its metal framework consists of a trigonal bipyramid with the equatorial triangle formed by iridium atoms. The mean values of the Fe–Ir, Ireq–Ireq′ and Irap–Ireq distances are 2.943, 2.708, 2.991 A, respectively. The monoanion [Fe2Ir3(CO)14]– was obtained from [Fe(CO)4]2– and [Ir(CO)2Cl2]–. The salt [PPh4][Fe2Ir3(CO)14](2) crystallizes in the orthorthombic space group P212121 with unit-cell dimensions a= 12.461(5), b= 14.306(5), c= 23.504(6)A, and Z= 4. Its metallic framework is comprised of an iridium triangle capped on opposite side by two iron atoms. The mean values of the Fe–Ir and Ir–Ir distances are 2.648 and 2.708 A, respectively. In the derivative (1) the trigonal bipyramid is considerably elongated in the direction of the apical atoms, When compared with that in (2). This elongation is consistent with the increased number of cluster valence electrons: 76 in (1) and 72 in (2).

Published
1989

9. Structural variations, electrochemical properties and computational studies on monomeric and dimeric Fe-Cu carbide clusters, forming copper-based staple arrays.

Author

Della Pergola R, Bruschi M, Sironi A, Manassero M, Manassero C, Strumolo D, Fedi S, and Zanello P

Abstract

The halide ligands of [Fe(4)C(CO)(12)(CuCl)(2)](2-) (1) and [Fe(5)C(CO)(14)CuCl](2-) (2) can be displaced by N-, P- or S-donors. Beside substitution, the clusters easily undergo structural rearrangements, with loss/gain of metal atoms, and formation of Fe(4)Cu/Fe(4)Cu(3) metallic frameworks. Thus, the reaction of 1 with excess dppe yielded [{Fe(4)C(CO)(12)Cu}(2)(μ-dppe)](2-) (3). [{Fe(4)C(CO)(12)Cu}(2)(μ-pyz)](2-) (4) was obtained by reaction of 2 with Ag(+) and pyrazine. [Fe(4)C(CO)(12)Cu-py](-) (5) was formed more directly from [Fe(4)C(CO)(12)](2-), [Cu(NCMe)(4)](+) and pyridine. [Fe(4)Cu(3)C(CO)(12)(μ-S(2)CNEt(2))(2)](-) (6) and [{Fe(4)Cu(3)C(CO)(12)(μ-pz)(2)}(2)](2-) (7) were prepared by substitution of the halides of 1 with diethyldithiocarbamate and pyrazolate, in the presence of Cu(i) ions. All of these products were characterized by X-ray analysis. 3 and 4 and 5 are square based pyramids, with iron in the apical sites, the bridging ligands connect the two copper atoms in 3 and 4. 6 and 7 are octahedral clusters with an additional copper ion held in place by the two bridging anionic ligands, forming a Cu(3) triangle with Cu-Cu distances ranging 2.63-3.13 Å. In 7, an additional unbridged cuprophilic interaction (2.75 Å) is formed between two such cluster units. DFT calculations were able to reproduce the structural deformations of 3-5, and related their differences to the back-donation from the ligand to Cu. Additionally, DFT found that, in solution, the tight ion pair [NEt(4)](2)7 is almost isoenergetic with the monomeric form. Thus, 3, 4 and 7 are entities of nanometric size, assembled either through conventional metal-ligand bonds or weaker electrostatic interactions. None of them allows electronic communication between the two monomeric units, as shown by electrochemistry and spectroelectrochemical studies. (dppe = PPh(2)CH(2)CH(2)PPh(2), pyz = pyrazine C(4)N(2)H(4), py = pyridine C(5)H(5)N, pz = pyrazolate C(3)N(2)H(3)(-)).

Published
2011
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10. A new water-soluble copper(II) complex as a selective fluorescent sensor for azide ion.

Author

Dhara K, Saha UC, Dan A, Sarkar S, Manassero M, and Chattopadhyay P

Subjects
Models, Molecular, Molecular Conformation, Solubility, Solutions, Spectrometry, Fluorescence, Temperature, Azides analysis, Coordination Complexes chemistry, Copper chemistry, Fluorescent Dyes chemistry, Organometallic Compounds chemistry, Water chemistry
Abstract

{[Cu(2)(H(2)L)(OH)(H(2)O)].(ClO(4))(2)(H(2)O)} (1) serves as a selective azide ion fluorescent sensor in aqueous medium. 1 binds with N(3)(-) to give [Cu(6)(HL)(2)(mu(1,1)-N(3))(6)] (2) which imposes rigidity and decreases the non-radiative decay of the excited state to give rise to fluorescent enhancement. 1 is highly selective over other various anions in aqueous medium.

Published
2010
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11. Tetranuclear copper(ii)-Schiff-base complexes as active catalysts for oxidation of cyclohexane and toluene.

Author

Roy P and Manassero M

Abstract

Three new Cu(ii) complexes, [Cu(4)(O)(L(n))(2)(CH(3)COO)(4)] where HL(1) = 4-methyl-2,6-bis(2-fluoroethyliminomethyl) phenol for complex , HL(2) = 4-methyl-2,6-bis(2-chloroethyliminomethyl) phenol for complex .0.25CH(3)CN and HL(3) = 4-methyl-2,6-bis(2-bromoethyliminomethyl) phenol for complex have been synthesized and characterized by elemental analysis, FTIR, UV-vis spectroscopy, and electrospray ionization mass spectroscopy. The structure of complex .0.25CH(3)CN has also been confirmed by single crystal X-ray diffraction analysis. These complexes have been found to be active catalysts for the oxidation of cyclohexane and toluene in the presence of hydrogen peroxide as the oxidant under mild conditions. Cyclohexane is oxidized to yield cyclohexanol and cyclohexanone, whereas toluene is oxidized to benzyl alcohol and benzaldehyde.

Published
2010
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12. Four mu4-oxo-bridged copper(II) complexes: magnetic properties and catalytic applications in liquid phase partial oxidation reactions.

Author

Roy P, Nandi M, Manassero M, Riccó M, Mazzani M, Bhaumik A, and Banerjee P

Subjects
Adsorption, Catalysis, Crystallography, X-Ray, Hydrogen Peroxide chemistry, Models, Molecular, Molecular Conformation, Nitrogen chemistry, Nitrous Oxide chemistry, Organometallic Compounds chemical synthesis, Oxidation-Reduction, Phenol chemistry, Schiff Bases chemistry, Spectrophotometry, Infrared, Spectrophotometry, Ultraviolet, Copper chemistry, Magnetics, Organometallic Compounds chemistry
Abstract

Four copper(II) complexes, [Cu(4)(O)(L(n))(2)(CH(3)COO)(4)] with N(2)O-donor Schiff-base ligands, where HL(1) = 4-methyl-2,6-bis(cyclohexylmethyliminomethyl)phenol for complex 1, HL(2) = 4-methyl-2,6-bis(phenylmethyliminomethyl)phenol for complex 2 x CH(3)CN, HL(3) = 4-methyl-2,6-bis(((3-tri-fluoromethyl)phenyl)methyliminomethyl)phenol for complex 3, HL(4) = 4-methyl-2,6-bis(((4-tri-fluoromethyl)phenyl)methyliminomethyl)phenol for complex 4, were synthesized and characterized by elemental analysis, FT-IR, UV-vis spectroscopy and finally by single crystal X-ray diffraction study. X-Ray analysis reveals that all of these are mu(4)-oxo-bridged tetrameric copper(II) complexes. Four copper atoms arrange themselves around an oxygen atom tetrahedrally. Magnetic susceptibility measurements show the existence of very strong antiferromagnetic coupling among these ions (J = -210.1 to -271.3 cm(-1)), mediated by the oxygen atoms. Catalysis of the epoxidation of cyclohexene, styrene, alpha-methylstyrene and trans-stilbene by these complexes has been carried out homogeneously as well as heterogeneously by immobilizing the metal complexes over 2D-hexagonal mesoporous silica. The results obtained in both the catalytic conditions show that the olefins are converted to the respective epoxides in good yield together with high selectivity.

Published
2009
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13. Reactivity of 1,3-bis(2-pyridyl)benzene, N--CH--N, with gold(III) chlorides: salts, adducts and cyclometalated pincer derivatives. Crystal and molecular structures of [HN--CH--N][AuCl4], [Au(N--C--N)Cl][PF6] and [Au(N--C--N)Cl(PPh3)2][PF6].

Author

Stoccoro S, Alesso G, Cinellu MA, Minghetti G, Zucca A, Manassero M, and Manassero C

Abstract

The reaction of 1,3-bis(2-pyridyl)benzene, N--CH--N, with H[AuCl(4)] has been studied under different conditions. Mono- ([N--CH--NH][AuCl(4)]) and di-protonated salts ([HN--CH--NH][AuCl(4)](2)), as well as an adduct, [(N--CH--N)(AuCl(3))(2)], have been isolated. Very rare cyclometalated pincer derivatives, [Au(N--C--N)Cl](+) have been obtained as different salts, either by transmetallation from the corresponding mercury(ii) derivative, [Hg(N--C--N)Cl], or by direct C-H activation. The structures in the solid state of [N--CH--NH][AuCl(4)] and [Au(N--C--N)Cl][PF(6)] have been solved by X-ray diffraction. Reaction of the pincer derivatives with PPh(3), dppm (bis(diphenylphosphino)methane) and dppe (1,2-bis(diphenylphosphino)ethane) occurs with displacement of the coordinated nitrogen atoms to afford [Au(N--C--N)(Cl)(PPh(3))(2)](+), [Au(N--C--N)(Cl)(dppm)(2)](+) and [Au(N--C--N)(Cl)(dppe)](+), respectively. The X-ray structure of [Au(N--C--N)(Cl)(PPh(3))(2)][PF(6)] confirms that the ligand N--C--N is only sigma-carbon bonded and the PPh(3) molecules are in a trans-arrangement. The pattern of the (31)P{(1)H}NMR spectrum of [Au(N--C--N)(Cl)(dppm)(2)](+), a pair of "triplets", deserves comments: the spectrum is not of the A(2)X(2) type but a case of a deceptively simple AA'XX' spin system.

Published
2009
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14. Cis influence in trans-Pt(PPh3)2 complexes.

Author

Rigamonti L, Manassero C, Rusconi M, Manassero M, and Pasini A

Abstract

The cis influence of a series of anionic ligands X and Y has been evaluated through the magnitude of the Pt-P coupling constants for compounds of formula trans-[PtXY(PPh(3))(2)]. The order of decreasing cis influence was found to be I > Cl > SePh approximately SPh approximately SEt > NO(3) > AcO approximately NO(2) > H > Me > Ph > mtc (mtc = N,N-dimethylmonothiocarbamato-S); moreover, the cis influences of the various ligands was found to be additive. The X-ray structures of three representative compounds (t-: X = Cl, Y = NO(3); t-: X = Cl, Y = AcO and t-: X = Y = NO(2)) have also been determined.

Published
2009
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15. Synthesis and properties of gold alkene complexes. Crystal structure of [Au(bipy(oXyl))(eta(2)-CH(2)=CHPh)](PF(6)) and DFT calculations on the model cation [Au(bipy)(eta(2)-CH(2)=CH(2))](+).

Author

Cinellu MA, Minghetti G, Cocco F, Stoccoro S, Zucca A, Manassero M, and Arca M

Abstract

Unprecedented 16-electron gold(i) olefin complexes of general formula [Au(bipy(R,R'))(eta(2)-olefin)](PF(6)) and [Au(2)(bipy(R,R'))(2)(mu-eta(2):eta(2)-diolefin)](PF(6))(2) (bipy(R,R') = 6-substituted-2,2'-bipyridine) have been prepared by reaction of dinuclear gold(III) oxo complexes [Au(2)(bipy(R,R'))(2)(mu-O)(2)](PF(6))(2) with the appropriate olefin. The X-ray crystal structures of two mononuclear complexes (olefin = styrene) show in-plane coordination of the olefin and a C[double bond, length as m-dash]C bond distance considerably lengthened with respect to the free olefin. The spectroscopic properties of the complexes are discussed and compared with those of analogous d(10) metal derivatives. Both structural and spectroscopic information indicate a substantial contribution of pi-back-donation to the Au-olefin bond in the three-coordinate species. Theoretical calculations carried out at the hybrid-DFT level on the model compound [Au(bipy)(eta(2)-CH(2)[double bond, length as m-dash]CH(2))](+) show excellent agreement with the experimental findings giving in addition an estimate of a pi-back-bonding contribution higher than that of the sigma-bonding.

Published
2006
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16. Reaction of gold(III) oxo complexes with alkenes. Synthesis of unprecedented gold alkene complexes, [Au(N,N)(alkene)][PF6]. Crystal structure of [Au(bipy(ip))(eta2-CH2=CHPh)][PF6] (bipy(ip) = 6-isopropyl-2,2'-bipyridine).

Author

Cinellu MA, Minghetti G, Stoccoro S, Zucca A, and Manassero M

Abstract

Gold alkene complexes [Au(bipyR)(eta2-alkene)][PF6] (bipyR = 6-alkyl-2,2'-bipyridine) have been obtained by reaction of gold(III) oxo complexes [Au2(bipyR)2(mu-O)2][PF6]2 with alkenes. The crystal structure of the styrene adduct [Au(bipy(ip))(eta2-CH2=CHPh)][PF6] (bipy(ip) = 6-isopropyl-2,2'-bipyridine) has been solved by X-ray analysis.

Published
2004
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