A single-crystal electron paramagnetic resonance, 13C and 1H electron nuclear double resonance study of tetra-n-butylammonium-bis(1,2-dicyanoethylene-1,2-dithiolato)aurate(II), [(n-C4H9)4N]2[AuII(mnt)2]

Ihlo, L.; Böttcher, R.; Olk, Ruth‐Maria; Kirmse, R.

doi:10.1016/s0020-1693(98)00163-7

Cited by 23 publications

(14 citation statements)

References 27 publications

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“…The common oxidation states for gold and silver (M) are +1 and +3 with paramagnetic, mononuclear d 9 M(II) complexes being especially rare. Many of the reported formal M(II) mononuclear species are often better described as ligand-radical species with delocalisation of the unpaired electron into ligand orbitals, 1,2 while the formation of diamagnetic M(II)-M(II) bonded species, for example via oxidative addition of halogens to binuclear Au(I) derivatives, is also common. 3 Gold: Genuine mononuclear Au(II) compounds are rare.…”

Section: Introductionmentioning

confidence: 99%

“…The structure of the formal Au(II) complex ( n Bu 4 N) 2 [Au(mnt) 2 ] (mnt ) maleonitriledithiolate), obtained as a green, air-sensitive product by reaction of the Au(III) species, n Bu 4 N[Au III (mnt) 2 ], with one equivalent of n Bu 4 N[BH 4 ], shows 9 the Au center bound to four S donors in a square-planar geometry with all Au-S bond lengths equivalent [Au-S ) 2.4156(7) Å]. Detailed EPR 10 and ENDOR 2 ( n Bu 4 N) 2 [Ni II (mnt) 2 ] as a diamagnetic host gave spin-Hamilton parameters g x ) 1.985, g y ) 2.005, g z ) 2.016, A x ) -39.6, A y ) -40.4, A z ) -41.2 K. These data, together with extended Hu ¨ckel theory molecular orbital calculations, confirmed that in ( n Bu 4 N) 2 [Au(mnt) 2 ] ca. 60% of the unpaired electron density within the singly occupied molecular orbital (SOMO) is localized on the S donors and only ca.…”

Section: Introductionmentioning

confidence: 99%

“…8% is localized on the Au center. 2 More recently, a stable, monomeric Au(II) complex has been reported with hematoporphyrin, 11 in which the sixcoordinate Au center is bound to the hematoporphyrin macrocycle and two water molecules are coordinated axially. The EPR spectrum of this complex is dominated by an intense signal attributed to a stable free radical; a less intense signal containing nine lines due to the interaction of the unpaired electron with the four coordinated N atoms is also observed.…”

Section: Introductionmentioning

confidence: 99%

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Redox Non-innocence of Thioether Macrocycles: Elucidation of the Electronic Structures of Mononuclear Complexes of Gold(II) and Silver(II)

et al. 2006

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The mononuclear +2 oxidation state metal complexes [Au([9]aneS(3))(2)](2+) and [Ag([18]aneS(6))](2+) have been synthesized and characterized crystallographically. The crystal structure of the Au(II) species [Au([9]aneS(3))(2)](BF(4))(2) shows a Jahn-Teller tetragonally distorted geometry with Au-S(1) = 2.839(5), Au-S(2) = 2.462(5), and Au-S(3) = 2.452(5) A. The related Ag(II) complex [Ag([18]aneS(6))](ClO(4))(2) has been structurally characterized at both 150 and 30 K and is the first structurally characterized complex of Ag(II) with homoleptic thioether S-coordination. The single-crystal X-ray structure of [Ag([18]aneS(6))](ClO(4))(2) confirms octahedral homoleptic S(6)-thioether coordination. At 150 K, the structure contains two independent Ag(II)-S distances of 2.569(7) and 2.720(6) A. At 30 K, the structure retains two independent Ag(II)-S distances of 2.615(6) and 2.620(6) A, with the complex cation retaining 3-fold symmetry. The electronic structures of [Au([9]aneS(3))(2)](2+) and [Ag([18]aneS(6))](2+) have been probed in depth using multifrequency EPR spectroscopy coupled with DFT calculations. For [Au([9]aneS(3))(2)](2+), the spectra are complex due to large quadrupole coupling to (197)Au. Simulation of the multifrequency spectra gives the principal g values, hyperfine (A) and quadrupole (P) couplings, and furthermore reveals non-co-incidence of the principal axes of the P tensor with respect to the A and g matrices. These results are rationalized in terms of the electronic and geometric structure and reveal that the SOMO has ca. 30% Au 5d(xy)() character, consistent with DFT calculations (27% Au character). For [Ag([18]aneS(6))](2+), detailed EPR spectroscopic analysis confirms that the SOMO has ca. 26% Ag 4d(xy)() character and DFT calculations are consistent with this result (22% Ag character).

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Redox Non-innocence of Thioether Macrocycles: Elucidation of the Electronic Structures of Mononuclear Complexes of Gold(II) and Silver(II)

et al. 2006

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“…Peculiar line spacings have been reported previously for 197 Au ( I = 3 / 2 ) and 191,193 Ir spectra. There have been reports of quartets in dilute single-crystal spectra of Au complexes with smaller or larger central spacings, but no analysis or interpretation was offered. An EPR spectrum of a Ir 2 complex analogous to 2 was reported with the expected high-field septet, but with unequal spacings (the low-field and midfield features were not resolved).…”

Section: Introductionmentioning

confidence: 99%

Analysis of Electron Paramagnetic Resonance Spectra with Very Large Quadrupole Couplings

et al. 2002

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Frozen solution electron paramagnetic resonance (EPR) spectra are reported for [(η 4 -cod)Rh(µ-RNNNR) 2 -Ir(CO) 2 ] + (cod ) 1,5-cyclooctadiene), [(PPh 3 )(CO)Rh(µ-RNNNR) 2 Ir(CO)(PPh 3 )] + (R ) p-tolyl) and [Tp′Ir-(CO)(PPh 3 ] + (Tp′ ) hydrotris(3,5-dimethylpyrazolyl)borate). In the first spectrum, the Rh hyperfine coupling dominates and there are no significant quadrupolar effects. In the second spectrum, the low-field (g x and g y ) features are 1:2:1 triplets rather than 1:1:1:1 quartets (I ) 3 / 2 for 191 Ir and 193 Ir), and in the third, the x and y features appear to be doublets. These anomalies result from the very large quadrupole moment for the iridium isotopes. This can be partially understood from a perturbation theory treatment, but quantitative simulations require direct matrix diagonalization and careful treatment of the problem, with respect to the orientation of the electron spin and nuclear spin quantization axes. The theoretical aspects of the calculations are presented, together with an interpretation of the results in terms of the electronic structures of the complexes.

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“…With respect to Cu, the isotropic hyperfine coupling a is predicted to be 5995 MHz (1978×10 −4 cm −1 ) for one electron spin occupies in the 4s orbital, and the anisotropic hyperfine coupling P is1197 MHz (395×10 −4 cm −1 ) in a 3d orbital [18] . The spin densities that an unpairedelectron is distributed in the 4s and 3d orbitals of Cu are accordingly calculated as follows: ρ 4s = A 0 /a = 0.043, ρ 3d = T z″ /(2P·2/7) = 0.351, where 2/7 is the angular factor of the orbit [19] . The total spin density is ρ 4s + ρ 3d = 0.394, implying that a majority of spin of the unpaired-electron is distributed in the molecular orbitals of ligands.…”

Section: Single Crystal Epr and Dft Calculationmentioning

confidence: 99%

Crystal structure and single crystal EPR of (NH4)2(15-crown-5)3[Cu(mnt)2] and (NH4)2(benzo-15-crown-5)4[Cu(mnt)2]·0.5H2O

et al. 2007

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The X-ray crystal structures of (NH 4 ) 2 (15-crown-5) 3 [Cu(mnt) 2 ] (1) and (NH 4 ) 2 (benzo-15-crown-5) 4 -[Cu(mnt) 2 ]·0.5H 2 O (2) were determined. Two single crystals are composed of distinct structures of ammonium-crown ether supramolecular cation and [Cu(mnt) 2 ] 2− anion. The triple-decker dication in complex 1 and a sandwich dimmer in complex 2 were observed. X-Band EPR studies on the single crystals of both complex 1 and complex 2 have been carried out at room temperature, which revealed that complex 2 showed a perfect hyperfine structure of Cu whereas that of complex 1 could not be observed. The principal values and direction cosines of the principal axes of the g and A tensors were computed by a least-squares fitting procedure. The spin density of Cu(II) was estimated according to the principal values of the A tensors and compared well with the results calculated based on DFT method. supramolecular cation, H-bonding interaction, EPR, g and A tensors, DFT In order to prepare novel molecular materials, many dithiolene compounds were investigated during decades [1][2][3] . The molecular materials based on M(mnt) 2 (M= Ni, Pd or Pt) have increasingly attracted attention because of their novel magnetic property [4][5][6][7] . In this paper, the crystal structure and single-crystal EPR of ion-pair complex which consists of supramolecular cation of ion-crown ether and [Cu(mnt) 2 ] 2− anion were studied on two salts, (NH 4 ) 2 (15-crown-5) 3 [Cu(mnt) 2 ] (1) and (NH 4 ) 2 (benzo-15-crown-5) 4 [Cu(mnt) 2 ]·0.5H 2 O (2). The clear EPR spectra of two single crystals were observed. Many EPR data were collected in three orthogonal planes. g 2 and A 2 tensor have been rigorously calculated using a least-squares-fitting technique [8] , specially adapted to non-coincident g and A tensor systems. The principle values of g and A, as well as the direction cosines of their principal axes with respect to the reference system, are obtained. The spin density of Cu(II) were estimated according to the principal values of the A tensors and compared well with the results calculated based on DFT calculation.

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A single-crystal electron paramagnetic resonance, 13C and 1H electron nuclear double resonance study of tetra-n-butylammonium-bis(1,2-dicyanoethylene-1,2-dithiolato)aurate(II), [(n-C4H9)4N]2[AuII(mnt)2]

Cited by 23 publications

References 27 publications

Redox Non-innocence of Thioether Macrocycles: Elucidation of the Electronic Structures of Mononuclear Complexes of Gold(II) and Silver(II)

Redox Non-innocence of Thioether Macrocycles: Elucidation of the Electronic Structures of Mononuclear Complexes of Gold(II) and Silver(II)

Analysis of Electron Paramagnetic Resonance Spectra with Very Large Quadrupole Couplings

Crystal structure and single crystal EPR of (NH4)2(15-crown-5)3[Cu(mnt)2] and (NH4)2(benzo-15-crown-5)4[Cu(mnt)2]·0.5H2O

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