Axial Bonding Capabilities of Square Planar d<sup>8</sup>-ML<sub>4</sub>Complexes. Theoretical Study and Structural Correlations

Aullón, Gabriel; Álvarez, Santiago

doi:10.1021/ic951643w

Cited by 89 publications

(85 citation statements)

References 79 publications

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“…The 29 Si and 119 Sn NMR signals for the (DPE)AuCl complexes appear at higher fields than those of the free ligands, which is in agreement with the formation of pentacoordinate species. According to X-ray crystallography, the three complexes exhibit close AuE contacts in the solid state and the geometry around the pentacoordinate group 14 center tends to trigonal bipyramidal with the gold and halogen atoms in apical positions ( Table 5).…”

Section: -Z Interaction With Group 14 Elementssupporting

confidence: 73%

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σ-Acceptor, Z-type ligands for transition metals

2011

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The ability of Lewis acids to coordinate to transition metals as s-acceptor ligands was recognized as early as in the 1970's, but so-called Z-type ligands remained curiosities until the early 2000's. Over the last decade, significant progress has been made in this area, especially via the incorporation of Lewis acid moieties into multidentate, ambiphilic ligands. Our understanding of the nature and influence of TM -Z interactions has considerably improved and the scope of Lewis acids susceptible to behave as s-acceptor ligands has been significantly extended. This feature article summarizes these recent achievements.

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Section: -Z Interaction With Group 14 Elementssupporting

confidence: 73%

“…29 Slight deviation of the central metal from planarity can nevertheless be observed, especially for strong M -SO 2 interactions. This means that the coordination of the Lewis acid does not significantly affect the nominal square-planar geometry of the metal fragment.…”

Section: Unsupported M -Z Interactionsmentioning

confidence: 99%

σ-Acceptor, Z-type ligands for transition metals

2011

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“…A number of metals are known to fulfill this role but Pt II (d 8 ) is the donor center par excellence, [1, 4,9,[14][15][16][17][18] while among the acceptors, Ag…”

Section: Abstract: the Dinuclear Pt-au Complex [(Cnc)(pph 3 )Ptau(pphmentioning

confidence: 99%

“…[17] Scalar relativistic effects were incorporated by applying the zeroth-order regular approximation (ZORA). [18] This level of theory is denoted BP86-D3/TZ2P+//BP86-D3/6-31G(d)&SDD+f(Pt, Au).…”

Section: Computational Detailsmentioning

confidence: 99%

Unusual Metal–Metal Bonding in a Dinuclear Pt–Au Complex: Snapshot of a Transmetalation Process

et al. 2016

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The dinuclear Pt-Au complex [(CNC)(PPh 3 )PtAu(PPh 3 )](ClO 4 ) (2) (CNC = 2,6-diphenylpyridinate) has been prepared. Its crystal structure shows a rare metal-metal bonding situation, with very short Pt-Au and Au-C ipso (CNC) distances and dissimilar Pt-C ipso (CNC) ) is a field which is attracting a considerable attention in chemistry. These interactions have proven to be a powerful tool for crystal engineering, [1][2][3][4][5] and the complexes containing them show interesting photophysical and photochemical properties related to the occurrence of M-M bonds. [6, 7] Besides, the interest on these systems has increased lately because species containing this kind of interactions play a central role in cooperative catalysis. [8] For example, complexes with Pt-Au, Pt-Cu or Pt-Ag bonds have been identified in either gas phase or in solution as intermediates in transmetalation reactions involving methyl groups, [9][10][11] whereas Pd-Au or Pd-Cu species have been proposed as transition states in aryl ligand interchange processes. [12, 13] [8]The M-M interactions described above are of dative nature and are established between a basic donor metallic center and an acidic acceptor metal. A number of metals are known to fulfill this role but Pt II (d 8 ) is the donor center par excellence, [1, 4,9,[14][15][16][17][18] while among the acceptors, Ag) is by far the most representative example. [19,20] In [29] with PPh 3 . The crystal structure of 1 has been determined by X-ray diffraction and shows the expected square planar coordination around the platinum (see Figure S3 and Table S1 The crystal structure of 2 has been determined by X-ray diffraction (see Figure 1, and a selection of relevant bond distances and angles is included in the caption. ; R = PPh 3 , X = Cl, 2.792(1) Å). Supporting Information for details). A drawing of its complex cation is shown in[23] Moreover, a striking feature of 2 is the interaction between the Au center and the ipso carbon of one of the phenylene rings of the CNC ligands. Thus, the Au-C7 distance is intriguingly short. Concomitantly, the Pt-C7 distance becomes significantly longer than the Pt-C13 one, the later being in the typical range found for Pt(II) complexes containing this or quite similar CNC ligands. [15, 16,31,32] The C7 phenylene ring remains perfectly planar. However, while the rest of the CNC ligand remains coplanar with the square planar environment of the Pt center, the C7 ring remarkably deviates from this plane (23.1(1)º).The bonding situation involving Pt, Au and C7 atoms found in the solid state for 2 does not to fit into the traditional model of square planar Pt(II)→M donor acceptor complexes. Thus, the Pt-Au line deviates considerably from the perpendicular to the Pt-N-C13 plane and the Pt-Au-P2 line bends 152.38(2)º), with the result of the Au atom leaning towards C7 (Au-Pt-C 7 angle of 52.7(1)º). This kind of situation, although reported in some examples, [9, 15] remained unstudied so far.[33] in complex 2 can be gained by means of the EDA-N...

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“…In other words, the rhodium center of the cationic complex is a Lewis acid that plays the role of the proton in the ammonium salts. Precedents of d 8 squareplanar metals that act as Lewis acids are known, [13] and the existence of bonding that is as weak as the Co···Rh interaction found herein and the corresponding pyramidali- zation of the metal coordination sphere have been explained with molecular-orbital arguments.…”

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confidence: 66%

Polyhedral Interconversion Coupled with Proton Transfer between an Ammonium Cation and the [Co(CO)₄]⁻ Ion

2006

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Proton transfer between ammonium cations and [CoL(CO) 3 ]À ions (L = CO, PR 3 ) has been illustrated by Brammer et al.[1] through a series of crystal structures according to the structure-correlation principle, which states that "if a correlation can be found between two or more independent parameters describing the structure of a given fragment in a variety of environments, then the correlation function maps a minimum energy path in the corresponding parameter space".[2] The two ends of the proton transfer reaction correspond to an ionic pair formed by an ammonium cation and the [CoL(CO) 3 ]À ion (1 a) and independent amine and hydrido carbonyl complexes 1 b. The structures analyzed by Brammer et al. correspond to compounds with NÀH···Co hydrogen bonds, a behavior consistent with the acidity of the hydrido carbonyl complex in water. [3] According to the structure-correlation principle, the variety of H···Co distances found (between 2.63 for a NÀH···Co hydrogen-bonded species and 1.43 for the hydrido complex) should correspond to snapshots along the proton-transfer reaction coordinate. Since the coordination spheres of both the N and Co atoms are significantly affected by the progress of the protontransfer reaction, these systems provide an excellent opportunity to test the applicability of the polyhedral-shape measures as reaction coordinates and to correlate the potential-energy surface with the structural evolution. Therefore, the aim of this communication is to show how DFT calculations provide an energy profile for such a reaction that accounts for the fine details of the distribution of structures along the path and how the proton transfer is coupled to changes in the coordination polyhedra of the N and Co atoms. An outcome of this study is that the energy and the stereochemical changes that accompany the proton transfer can be described as a function of a single parameter, the generalized polyhedral-interconversion coordinate [4] for the transformation of a [CoL(CO) 3 ] À (L = ligand) tetrahedron into a vacant trigonal bipyramid.To represent the general case of an ammonium cation, we took the NH 4 + ion as the simplest example, whereas the family of the [CoL(CO) 3 ]À ions was represented in our calculations by the [Co(CO) 4 ] À ion. To explore the potentialenergy surface, we calculated a linear-transit reaction coordinate for the NH 4 ·[CoL(CO) 3 ] aggregate keeping the Co···H distance fixed and optimizing the rest of the geometry.[5] The two minima and one maximum obtained were fully optimized and could be characterized as stationary points on the potential-energy surface through frequency analysis (geometries and frequencies for the three stationary points are provided in the Supporting Information). The two minima correspond to the two alternative hydrogen-bonding situations: a) N À H···Co, referred to herein as the ion pair, to avoid confusion with the second minimum, and b) N···HÀCo, which we term the hydrogen-bonded complex. The maximum corresponds to a transition state with a delocalized hydrogen bo...

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Axial Bonding Capabilities of Square Planar d⁸-ML₄Complexes. Theoretical Study and Structural Correlations

Cited by 89 publications

References 79 publications

σ-Acceptor, Z-type ligands for transition metals

σ-Acceptor, Z-type ligands for transition metals

Unusual Metal–Metal Bonding in a Dinuclear Pt–Au Complex: Snapshot of a Transmetalation Process

Polyhedral Interconversion Coupled with Proton Transfer between an Ammonium Cation and the [Co(CO)₄]⁻ Ion

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Axial Bonding Capabilities of Square Planar d8-ML4Complexes. Theoretical Study and Structural Correlations

Cited by 89 publications

References 79 publications

σ-Acceptor, Z-type ligands for transition metals

σ-Acceptor, Z-type ligands for transition metals

Unusual Metal–Metal Bonding in a Dinuclear Pt–Au Complex: Snapshot of a Transmetalation Process

Polyhedral Interconversion Coupled with Proton Transfer between an Ammonium Cation and the [Co(CO)4]− Ion

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Axial Bonding Capabilities of Square Planar d⁸-ML₄Complexes. Theoretical Study and Structural Correlations

Polyhedral Interconversion Coupled with Proton Transfer between an Ammonium Cation and the [Co(CO)₄]⁻ Ion