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51. Competition between the Hydride Ligands of Two Types in Proton Transfer to [{kappa(3)-P-CH3C(CH2CH2PPh2)(3)}RuH(eta(2)-BH4)]

Author

Golub, Igor E., Filippov, Oleg A., Belkova, Natalia V., Gutsul, Eugenii I., Epstein, Lina M., Rossin, Andrea, Peruzzini, Maurizio, and Shubina, Elena S.

Subjects
Hydrides, Borates, Proton transfer, Dihydrogen bonds, Ruthenium
Abstract

The interaction of the mixed hydrido-tetrahydridoborate ruthenium(II) complex [(Triphos) RuH(eta(2)-BH4)] [1; Triphos =kappa(3)-P-CH3C(CH2CH2PPh2)(3)] with alcohols of variable acidic strength [MeOH, FCH2CH2OH (MFE), CF3CH2OH (TFE), (CF3)(2)CHOH (HFIP), and (CF3)(3)COH (PFTB)] was the subject of a combined computational (DFT) and spectroscopic (VT FTIR, NMR) study. The experimental spectra suggests that RuH center dot center dot center dot HO bond formation precedes the protonation of 1, and H-2 evolution leads to the loss of boron and the formation of the dimetal-lic [{(Triphos) RuH}(2)(mu,eta(2):eta(2)-BH4)](+) cation. The experimentally determined basicity factor [Ej(RuH)] of the Ru-bound hydrido ligand of 1.43 is among the highest determined for ruthenium hydrides. Such high basicity leads to very easy proton transfer to the RuH ligand for strong alcohols (HFIP and PFTB). An alternative reaction pathway involving the migration of the bridging hydride (BHbr) to the ruthenium center is suggested for weaker proton donors (MeOH and TFE).

Published
2017

54. Amine Boranes Dehydrogenation Mediated by an Unsymmetrical Iridium Pincer Hydride: (PCN) vs (PCP) Improved Catalytic Performance

Author

Luconi, Lapo, primary, Osipova, Elena S., additional, Giambastiani, Giuliano, additional, Peruzzini, Maurizio, additional, Rossin, Andrea, additional, Belkova, Natalia V., additional, Filippov, Oleg A., additional, Titova, Ekaterina M., additional, Pavlov, Alexander A., additional, and Shubina, Elena S., additional

Published
2018
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60. Neutral transition metal hydrides as acids in hydrogen bonding and proton transfer: media polarity and specific solvation effects

Author

Levina, Vladislava A., Filippov, Oleg A., Gutsul, Evgenii I., Belkova, Natalia V., Epstein, Lina M., Lledos, Agusti, and Shubina, Elena S.

Subjects
Density functionals -- Usage, Hydrogen bonding -- Analysis, Infrared spectroscopy -- Usage, Oxidation-reduction reaction -- Analysis, Solvation -- Analysis, Transition metals -- Chemical properties, Chemistry
Abstract

Several experimental and computational studies are conducted to explain the structural and electronic properties of the various weak hydrogen-bonded complexes with organic bases. The various media polarity and the specific salvation effects observed in these compounds are also analyzed.

Published
2010

61. Mechanistic studies on the interaction of [([[kappa].sup.3]-P,P,P-N[P.sub.3])Ir[H.sub.3]] [N[P.sub.3] = N[(C[H.sub.2]C[H.sub.2]P[Ph.sub.2]).sub.3] with HB[F.sub.4] and fluorinated alcohols by combined NMR, IR, and DFT techniques

Author

Rossin, Andrea, Gutsul, Evgenii I., Belkova, Natalia V., Epstein, Lina M., Gonsalvi, Luca, Lleds, Agust, Lyssenko, Konstantin A., Peruzzini, Maurizio, Shubina, Elena S., and Zanobini, Fabrizio

Subjects
Alcohols -- Chemical properties, Density functionals -- Usage, Fluorination -- Analysis, Iridium -- Chemical properties, Nuclear magnetic resonance spectroscopy -- Usage, X-ray crystallography -- Usage, Chemistry
Published
2010

62. Dihydrogen Bonding and Proton Transfer from MH and OH Acids to Group 10 Metal Hydrides [(tBuPCP)MH] [tBuPCP = ?3-2,6-(tBu2PCH2)2C6H3; M = Ni, Pd]

Author

Osipova, Elena S., Belkova, Natalia V., Epstein, Lina M., Filippov, Oleg A., Kirkina, Vladislava A., Titova, Ekaterina M., Rossin, Andrea, Peruzzini, Maurizio, and Shubina, Elena S.

Subjects
M-H activation, Density functional calculations, Noncovalent interactions, IR spectroscopy, Hydrides
Abstract

The interactions of HA acids {indole, fluorinated alcohols, phenols, and [CpW(CO)3H] (2)]} with the title hydrides [(tBuPCP)MH] [M = Ni (1a), Pd (1b)] have been studied by a combination of spectroscopic (variable-temperature IR, NMR, UV/Vis) and computational (DFT/M06, AIM) methods in THF and toluene. The formation of the dihydrogen bond (DHB) 1···HA is the first step in a process leading to proton transfer and H2 evolution. The DHBs of 1 with 2 are much weaker than those of 1 with NH or OH acids, but the former complexes are more reactive. Kinetic studies of the reactions of 4-(4?-nitrophenylazo) phenol and [CpWH(CO)3] with 1b in THF gave activation enthalpies ?H? = 9.2 ± 0.4 and 6.5 ± 1.5 kcal mol-1 and activation entropies ?S? = -30 ± 1 and -35 ± 6 cal mol-1 K-1, respectively. Calculations revealed the (?2-H2)-like TS (?E? = 9.3 kcal mol-1) for the reaction of 1b with p-nitrophenol and the [Pd(?2-H2)]+OAr- complex as a local minimum at around 5 kcal mol-1 above the DHB adduct. In the reaction of 1b with 2, both the acidic WH and hydridic NiH or PdH bonds undergo heterolytic cleavage (?E? = 7.4 kcal mol-1) to yield the unusual ?,?1:1-H2 end-on complex. The ?,?1:1-H2 molecule transforms easily into the more stable ?2-H2 side-on tautomer, which eventually gives the bimetallic product after H2 evolution.

Published
2016

63. Experimental (IR, Raman) and computational analysis of a series of Pt[Br.sub.2] derivatives: vibrational coupling in the coordinated ethylene and Pt-Br modes

Author

Dub, Pavel A., Filippov, Oleg A., Belkova, Natalia V., Rodriguez-Zubiri, Mireia, and Poli, Rinaldo

Subjects
Raman spectroscopy -- Usage, Density functionals -- Usage, Ethylene -- Chemical properties, Infrared spectroscopy -- Usage, Platinum -- Electric properties, Platinum -- Optical properties, Chemicals, plastics and rubber industries
Published
2009

64. Intermolecular hydrogen bonding between neutral transition metal hydrides [eta(super 5)-C5H5]M(CO)(sub 3)H (M = Mo, W) and bases

Author

Belkova, Natalia V., Gutsul, Evgenii I., Filippov, Oleg A., Levina, Vladislava A., Valyaev, Dmitriy A, Epstein, Lina M., Liedos, Agusti, and Shubina, Elena S.

Subjects
Hydrogen bonding -- Optical properties, Hydrogen bonding -- Spectra, Infrared spectroscopy -- Analysis, Polarization (Light) -- Analysis, Chemistry
Abstract

The spectroscopic and theoretical evidence for the intermolecular hydrogen bond with neutral hydride complex as an acid is presented, where CpM-(CO)(sub 3)H hydride complexes (M = Mo, W) are chosen as they are less acidic than HCo(CO)(sub 4). Intermolecular dihydrogen bond (H...H) is found between two neutral hydride complexes using H3BNEt3 as a base.

Published
2006

65. Diverse world of unconventional hydrogen bonds

Author

Belkova, Natalia V., Shubina, Elena S., and Epstein, Lina M.

Subjects
Hydrogen bonding -- Structure, Hydrogen bonding -- Chemical properties, Transition metal compounds -- Structure, Transition metal compounds -- Chemical properties, Protons -- Research, Chemistry, Science and technology
Abstract

The view of unconventional intermolecular hydrogen bonds for organometallic complexes and transition-metal or main-group hydrides is presented. Their structures and spectroscopic manifestations are discussed and new developments in the field, especially the studies of the mechanism of proton transfer to organometallic hydrides are revealed.

Published
2005

77. Z−H Bond Activation in (Di)hydrogen Bonding as a Way to Proton/Hydride Transfer and H2 Evolution.

Author

Belkova, Natalia V., Filippov, Oleg A., and Shubina, Elena S.

Subjects
*DIHYDROGEN bonding, *PROTON transfer reactions, *HYDRIDE transfer reactions, *BORANES, *INTERMOLECULAR interactions
Abstract

Abstract: The ability of neutral transition‐metal hydrides to serve as a source of hydride ion H− or proton H+ is well appreciated. The hydride ligands possessing a partly negative charge are proton accepting sites, forming a dihydrogen bond, M−Hδ−⋅⋅⋅δ+HX (M=transition metal or metalloid). On the other hand, some metal hydrides are able to serve as a proton source and give hydrogen bond of M−Hδ+⋅⋅⋅X type (X=organic base). In this paper we analyse recent works on transition‐metal and boron hydrides showing i) how formation of an intermolecular complex between the reactants changes the Z−H (M−H and X−H) bond polarity and ii) what is the implication of such activation in the mechanisms of hydrides reactions. [ABSTRACT FROM AUTHOR]

Published
2018
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83. Mechanistic study of the protonation of [(k3-P,P,P-NP3)Ir(H)3] [NP3 = N(CH2CH2PPh2)3] by HBF4 and fluorinated alcohols through combined NMR, IR and DFT techniques

Author

Rossin, Andrea, Gutsul, Evgenii I., Belkova, Natalia V., Epstein, Lina M., Gonsalvi, Luca, Lledos, Agusti, Lyssenko Konstantin A., Peruzzini, M., Shubina, Elena S., and Zanobini, Fabrizio

Subjects
aminophosphine, iridium, dihydrogen bonding, DFT calculations, NMR
Abstract

The novel iridium(III) hydride [(?3-P,P,P-NP3)IrH3] [NP3 = N(CH2CH2PPh2)3] was synthesized and characterized by spectroscopic methods and X-ray crystallography. Its reactivity with strong (HBF4) and medium-strength [the fluorinated alcohols 1,1,1-trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoroisopropanol (HFIP)] proton donors was investigated through low-temperature IR and multinuclear NMR spectroscopy. In the case of the weak acid TFE, the only species observed in the 190-298 K temperature range was the dihydrogen-bonded adduct between the hydride and the alcohol, while with the stronger acid HBF4, the proton transfer was complete, giving rise to a new intermediate [(?3-P,P,PNP3)IrH4].With a medium-strength acid like HFIP, two different sets of signals for the intermediate species were observed besides dihydrogen bond formation. In all cases, the final reaction product at ambient temperature was found to be the stable dihydride [(?4-NP3)IrH2], after slow molecular dihydrogen release. The nature of the short-living species was investigated with the help of density functional theory calculations at the M05-2X//6-31þþG(df,pd) level of theory

Published
2010

84. Competition between the Hydride Ligands of Two Types in Proton Transfer to [{κ3- P-CH3C(CH2CH2PPh2)3}RuH(η2-BH4)].

Author

Golub, Igor E., Filippov, Oleg A., Belkova, Natalia V., Gutsul, Eugenii I., Epstein, Lina M., Rossin, Andrea, Peruzzini, Maurizio, and Shubina, Elena S.

Subjects
HYDRIDES, LIGANDS (Chemistry), COORDINATION compounds, CHEMICAL reactions, PROTONS, COMPLEX compounds
Abstract

The interaction of the mixed hydrido-tetrahydridoborate ruthenium(II) complex [(Triphos)RuH(η2-BH4)] [ 1; Triphos = κ3- P-CH3C(CH2CH2PPh2)3] with alcohols of variable acidic strength [MeOH, FCH2CH2OH (MFE), CF3CH2OH (TFE), (CF3)2CHOH (HFIP), and (CF3)3COH (PFTB)] was the subject of a combined computational (DFT) and spectroscopic (VT FTIR, NMR) study. The experimental spectra suggests that RuH ···HO bond formation precedes the protonation of 1, and H2 evolution leads to the loss of boron and the formation of the dimetallic [{(Triphos)RuH}2(µ,η2:η2-BH4)]+ cation. The experimentally determined basicity factor [ Ej(RuH)] of the Ru-bound hydrido ligand of 1.43 is among the highest determined for ruthenium hydrides. Such high basicity leads to very easy proton transfer to the RuH ligand for strong alcohols (HFIP and PFTB). An alternative reaction pathway involving the migration of the bridging hydride (BHbr) to the ruthenium center is suggested for weaker proton donors (MeOH and TFE). [ABSTRACT FROM AUTHOR]

Published
2017
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85. Binuclear Copper(I) Borohydride Complex Containing Bridging Bis(diphenylphosphino) Methane Ligands: Polymorphic Structures of [(μ2-dppm)2Cu2(η²-BH4)2] Dichloromethane Solvate.

Author

Belkova, Natalia V., Golub, Igor E., Gutsul, Evgenii I., Lyssenko, Konstantin A., Peregudov, Alexander S., Makhaev, Viktor D., Filippov, Oleg A., Epstein, Lina M., Rossin, Andrea, Peruzzini, Maurizio, and Shubina, Elena S.

Subjects
METHANE, BORATES, CHEMICAL synthesis
Abstract

Bis(diphenylphosphino)methane copper(I) tetrahydroborate was synthesized by ligands exchange in bis(triphenylphosphine) copper(I) tetrahydroborate, and characterized by XRD, FTIR, NMR spectroscopy. According to XRD the title compound has dimeric structure, [(μ2-dppm)2Cu2(η2-BH4)2], and crystallizes as CH2Cl2 solvate in two polymorphic forms (orthorhombic, 1, and monoclinic, 2) The details of molecular geometry and the crystal-packing pattern in polymorphs were studied. The rare Twisted Boat-Boat conformation of the core Cu2P4C2 cycle in 1 is found being more stable than Boat-Boat conformation in 2. [ABSTRACT FROM AUTHOR]

Published
2017
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89. Dihydrogen Bonding in Complex (PP3)RuH(η1-BH4) Featuring Two Proton-Accepting Hydride Sites: Experimental and Theoretical Studies

Author

Belkova, Natalia V., primary, Bakhmutova-Albert, Ekaterina V., additional, Gutsul, Evgenii I., additional, Bakhmutov, Vladimir I., additional, Golub, Igor E., additional, Filippov, Oleg A., additional, Epstein, Lina M., additional, Peruzzini, Maurizio, additional, Rossin, Andrea, additional, Zanobini, Fabrizio, additional, and Shubina, Elena S., additional

Published
2013
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92. First Example of Hydrogen Bonding to Platinum Hydride

Author

Filippov, Oleg A., primary, Kirkina, Vladislava A., additional, Belkova, Natalia V., additional, Stoccoro, Sergio, additional, Zucca, Antonio, additional, Babakhina, Galina M., additional, Epstein, Lina M., additional, and Shubina, Elena S., additional

Published
2013
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95. Dihydrogen Bonding and Proton Transfer from MH and OH Acids to Group 10 Metal Hydrides [( tBuPCP)MH] [ tBuPCP = κ3-2,6-( tBu2PCH2)2C6H3; M = Ni, Pd].

Author

Osipova, Elena S., Belkova, Natalia V., Epstein, Lina M., Filippov, Oleg A., Kirkina, Vladislava A., Titova, Ekaterina M., Rossin, Andrea, Peruzzini, Maurizio, and Shubina, Elena S.

Subjects
*DIHYDROGEN bonding, *PROTON transfer reactions, *HYDRIDES, *ENTHALPY, *TAUTOMERISM
Abstract

The interactions of HA acids {indole, fluorinated alcohols, phenols, and [CpW(CO)3H] ( 2)]} with the title hydrides [( tBuPCP)MH] [M = Ni ( 1a), Pd ( 1b)] have been studied by a combination of spectroscopic (variable-temperature IR, NMR, UV/Vis) and computational (DFT/M06, AIM) methods in THF and toluene. The formation of the dihydrogen bond (DHB) 1···HA is the first step in a process leading to proton transfer and H2 evolution. The DHBs of 1 with 2 are much weaker than those of 1 with NH or OH acids, but the former complexes are more reactive. Kinetic studies of the reactions of 4-(4′-nitrophenylazo)phenol and [CpWH(CO)3] with 1b in THF gave activation enthalpies Δ H≠ = 9.2 ± 0.4 and 6.5 ± 1.5 kcal mol-1 and activation entropies Δ S≠ = -30 ± 1 and -35 ± 6 cal mol-1 K-1, respectively. Calculations revealed the (η2-H2)-like TS (Δ E≠ = 9.3 kcal mol-1) for the reaction of 1b with p-nitrophenol and the [Pd(η2-H2)]+OAr- complex as a local minimum at around 5 kcal mol-1 above the DHB adduct. In the reaction of 1b with 2, both the acidic WH and hydridic NiH or PdH bonds undergo heterolytic cleavage (Δ E≠ = 7.4 kcal mol-1) to yield the unusual µ,η1:1-H2 end-on complex. The µ,η1:1-H2 molecule transforms easily into the more stable η2-H2 side-on tautomer, which eventually gives the bimetallic product after H2 evolution. [ABSTRACT FROM AUTHOR]

Published
2016
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96. PCP Pincer Iridium Chemistry - Coordination of Pyridines to [( tBuPCP)IrH(Cl)].

Author

Titova, Ekaterina M., Silantyev, Gleb A., Filippov, Oleg A., Gulyaeva, Ekaterina S., Gutsul, Evgenii I., Dolgushin, Fedor M., and Belkova, Natalia V.

Subjects
BENZENE, AMINOPYRIDINES, NUCLEAR magnetic resonance, STEREOCHEMISTRY, WINDOWLESS energy-dispersive X-ray analysis, HYDROGEN bonding
Abstract

The complexes of [( tBuPCP)IrH(Cl)] { 1, tBuPCP = 1,3-bis[(di- tert-butylphosphanyl)methyl]benzene} with pyridine (py, 2), 4-aminopyridine (4apy, 3) and 2-aminopyridine (2apy, 4) have been synthesized and fully characterized by variable-temperature spectroscopy (NMR, IR, and UV/Vis). In each case, the reaction yields a mixture of cis- and trans-hydrido-chlorido isomers. The stereochemistry of the latter was confirmed by single-crystal X-ray analysis of 2a and 3a, which showed that the pyridine ligands coordinated opposite the aryl ring do not produce an additional twist of the pincer ligand but lead to the elongation of all bonds involving the iridium atom. The chlorido ligand becomes substantially labilized owing to the strong trans effect of the hydrido ligand, and that in 3a it is prone to intermolecular N-H ···Cl hydrogen bonding in the solid state. In the 2-aminopyridine complex 4, the intramolecular hydrogen bond to the chlorido ligand (isomer 4a′) is slightly more preferred over the N-H ···H bond (isomer 4a). The structures of the cis-hydrido-chlorido isomers 2b- 4b were established with the help of 15N-labeled pyridine. These isomers undergo fast ligand exchange on the NMR timescale that slows as the temperature decreases. The decoalescence temperature is the lowest for the 2-aminopyridine derivative 4b; therefore, it is the least stable. The repulsion between the tert-butyl groups of the pincer ligand and the o-NH2 group is the main reason for the lower stability of 4b. [ABSTRACT FROM AUTHOR]

Published
2016
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