Intermolecular Metal-Metal Bonds and Absorption Spectra of Some Nickel(II) and Palladium(II) Complexes of vic-Dioximes<sup>1</sup>

Banks, Charles V.; Barnum, Dennis W.

doi:10.1021/ja01551a004

Cited by 52 publications

(29 citation statements)

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“…The extra stability is basically due to an increase in entropy as a result of alteration from an octahedral structure of [Zn(H 2 O) 6 ] 2+ to a tetrahedral with a structure of [Zn-(BPG)] 2+ . On the other hand, the stability of all Ni(II)-BPG complexes are higher than the corresponding Zn(II)-BPG complexes; this confirms the stability magnitude, caused by the assumed Ni-Ni bond in solution, 39 as mentioned previously. Also, the stability of Ni(II) complexes, in many cases, could be higher than the corresponding Zn(II) complexes without the establishment of metal-metal bonding.…”

Section: Resultssupporting

confidence: 87%

“…38 In this case, the highest stability constants of the Ni(II) complexes over the Cu(II) complexes might be due to the possible formation of metal-metal bonding, as this type of bonding is confirmed in solid Vic-dioxime complexes. 39 Figure 4 shows the similarity in the distribution of Cu(II)-BPG species, with that of the Ni(II)-BPG system, but with eight species being tracked by the computer program. The species CuH 4 L formed almost in the same pH range as NiH 4 L, but with different distribution percentages at any pH.…”

Section: Resultsmentioning

confidence: 98%

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Potentiometric Study of the Coordination Tendency of 1,2-Bis(4-benzylpiperidine)glyoxime Toward Some Transition Metal Ions

2010

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A potentiometic study has been carried out to reveal the coordination properties of 1,2-bis(4-benzylpiperidine)glyoxime (BPG), via its reaction with certain transition metal ions, Ni 2+ , Cu 2+ , and Zn 2+ , and to determine the stability constants of the complexes formed. The experimental conditions were arranged to achieve all of the measurements and coordination in aqueous solution (mixed ethyl alcohol (10 %) and water (90 %)) at (25 ( 0.1)°C and an ionic background of 0.1 mol · dm -3 NaCl. The overall stability constants log n values of all species formed in solution together with the dissociation constants of the ligand were calculated by use of the SUPERQUAD computer program. The dissociation constants of the ligand BPG are 2.830, 6.066, 6.966, and 9.510. The chemical species present in the solution under our experimental conditions were demonstrated by the use of speciation diagrams.

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Section: Resultssupporting

confidence: 87%

Section: Resultsmentioning

confidence: 98%

Potentiometric Study of the Coordination Tendency of 1,2-Bis(4-benzylpiperidine)glyoxime Toward Some Transition Metal Ions

2010

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“…The Ni(II) ions line up with an average Ni---Ni distance of 3.233 Å. The Pd(II) and Pt(II) complexes exhibit similar structures with the Pd---Pd and Pt---Pt distances being 3.253 and 3.25 Å, respectively (13,14). As the M(II)---M(II) distances in these complexes are quite similar, the factor that governs the distances is attributed to the organic groups in the ligand.…”

Section: Square-planar Pd(ii) Complexesmentioning

confidence: 95%

Piezochromism and Related Phenomena Exhibited by Palladium Complexes

Takagi¹,

Noda²,

Itoh³

et al. 2004

Platinum Metals Review

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Piezochromic phenomena colour changes in solid specimens or solution samples induced by external pressures are explained by pressure perturbation to the HOMO and/or LUMO (highest occupied molecular orbital and/or lowest unoccupied molecular orbital) energy levels of the related electronic transition. The piezochromism of solid inorganic and organic materials has been investigated by examining phase transition phenomena. Specific electronic properties of the solids, acquired by tuning the external pressure, may be used as electronic devices and as pressure sensors.Changes in the absorption and emission spectra of metal complexes in solution are related to changes in solvent polarity at each pressure: a gradual increase of the dielectric constant of the solvent with pressure affects the energies of the HOMO and LUMO levels involved in the electronic transitions within the metal complexes, and a corresponding colour change may be observed. However, such a pressure perturbation to the dielectric constant of solvents is usually small (1) and the piezochromic effect of samples in solution is rather ambiguous partly because of the narrow range of applied pressures (< 5000 bar).It is known that the compressibility of solids is much smaller (< 0.001%) than that of liquids. This small compressibility is explained by the difficulty of intermolecular and/or interionic compression in the crystals that comprise the solid and by the difficulty of compression along the bond axis in the molecules or complex ions. For example, lateral compression between the chains takes place for alkylsilicon and alkylgermanium polymers at relatively low pressures (ca. 10,000 bar), followed by compression along the SiSi and GeGe axes at higher pressures (> 20,000 bar) (27). Moreover, deformation of compounds by the external pressure does not take place in a free way: there is a quantum mechanical restriction symmetry rules (8, 9) that governs the direction of deformation. Specific interactions, such as hydrogen bonding and ion-pair interactions, also perturb the structures at elevated pressures (10). In addition to knowing the symmetry rules, it is essential to comprehend the theories of electronic transitions and molecular symmetry and vibrations for a proper understanding of piezochromic effects (11). In this short review the effects of pressure perturbations on the absorption and emission spectra that are exhibited by solid palladium complexes are Piezochromic phenomena are explained by pressure perturbation to the HOMO and/or LUMO energy levels of the related electronic transition. The piezochromism of solid inorganic and organic materials has been investigated by examination of the phase transition phenomena. Specific electronic properties of the solids, acquired by tuning the external pressure, may be used as electronic devices and as pressure sensors. The effects of pressure perturbations on the absorption and emission spectra exhibited by solid palladium complexes are reviewed here. Related phenomena exhibited by platinum complexes and ot...

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“…), The metal-metal bonds formed in this type of packing are said to contribute enough stability to the crystal that it is insoluble in water, and the unique packing tends to prevent coprecipitation of other metals (9). Several studies have been inter preted as support for this hypothesis (7,8,9,10,88,76).…”

Section: Ilmentioning

confidence: 99%

“…The nickel-vic-dioxlmes exhibit a color band in their solid state spectra which is not found in their solution spectra.^ Previous workers have treated the chloroform solu tion spectra of the nickel-vlc-dioximes as being representa tive of their gas phase spectra (10,14,4). To do this requires that no unusual solvation effects are altering the chloroform solution spectra.…”

Section: General Considerationsmentioning

confidence: 99%

Solubility behavior of the nickel(II)-, palladium(II)-, and platinum(II)- complexes of some vic-dioximes

Smith

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Intermolecular Metal-Metal Bonds and Absorption Spectra of Some Nickel(II) and Palladium(II) Complexes of vic-Dioximes¹

Cited by 52 publications

References 6 publications

Potentiometric Study of the Coordination Tendency of 1,2-Bis(4-benzylpiperidine)glyoxime Toward Some Transition Metal Ions

Potentiometric Study of the Coordination Tendency of 1,2-Bis(4-benzylpiperidine)glyoxime Toward Some Transition Metal Ions

Piezochromism and Related Phenomena Exhibited by Palladium Complexes

Solubility behavior of the nickel(II)-, palladium(II)-, and platinum(II)- complexes of some vic-dioximes

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Intermolecular Metal-Metal Bonds and Absorption Spectra of Some Nickel(II) and Palladium(II) Complexes of vic-Dioximes1

Cited by 52 publications

References 6 publications

Potentiometric Study of the Coordination Tendency of 1,2-Bis(4-benzylpiperidine)glyoxime Toward Some Transition Metal Ions

Potentiometric Study of the Coordination Tendency of 1,2-Bis(4-benzylpiperidine)glyoxime Toward Some Transition Metal Ions

Piezochromism and Related Phenomena Exhibited by Palladium Complexes

Solubility behavior of the nickel(II)-, palladium(II)-, and platinum(II)- complexes of some vic-dioximes

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Intermolecular Metal-Metal Bonds and Absorption Spectra of Some Nickel(II) and Palladium(II) Complexes of vic-Dioximes¹