Origin and fine tuning of the stability of five-coordinated platinum(II) and palladium(II) species. A quantum-mechanical study

Desmarias, Normand; Adamo, Carlo; Panunzi, Barbara; Barone, Vincenzo; Giovannitti, Bruno

doi:10.1016/0020-1693(95)04703-c

Cited by 10 publications

(9 citation statements)

References 14 publications

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“…This effect has also been reported very recently by Markies et al. It has been proposed that the ability of a fifth ligand to bind to a d 8 metal, such as palladium or platinum, is enhanced if the coordinated ligands are strong π-acceptors. − This may explain why such an interaction was observed only when electron correlation was considered, as RHF theory does not adequately describe the π-back-donation interactions. The orientation of the weakly coordinated carbon monoxide parallel to the plane is consistent with such a postulate, indicating that the interaction is mainly π in character (refer to Figure )…”

Section: Resultssupporting

confidence: 55%

Ligand Substitution: An Assessment of the Reliability of ab Initio Calculations

et al. 1996

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Density functional methods and conventional ab initio molecular orbital methods have been compared in an investigation of the model ligand substitution reaction Pd. Full geometry optimizations were performed for each stationary point using a range of different basis sets, relativistic effective core potentials (RECPs), and levels of theory in order to ascertain a reliable and computationally inexpensive method for probing such reaction mechanisms. For geometries that compare well to experiment, electron correlation and double-valence basis sets with d-type polarization functions on the main group elements are essential. Geometries determined using small-core RECPs and nonlocal density functional theory compared favorably with those produced at the second-order Møller-Plesset (MP2) level, and good agreement with available experimental data was observed. The density functional reaction energetics, however, were poor, apparently due to an unrealistically high Pd-CO binding energy relative to the Pd-PH 3 binding energy. This error was reduced by the use of the Becke three-term hybrid exchange functional. The reaction barrier and reaction energy were predicted to be +15.0 kJ/mol and +5.1 kJ/mol, respectively, at the MP2 level with a medium basis set. Approximate large basis set CCSD(T) energetics were determined using an additivity scheme. This method predicted a stabilization of the 5-coordinate transition structure with respect to the 4-coordinate species, reducing the reaction barrier to +4.9 kJ/mol relative to the separated reactants. The associated reaction energy was +8.9 kJ/mol.

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Section: Resultssupporting

confidence: 55%

Ligand Substitution: An Assessment of the Reliability of ab Initio Calculations

et al. 1996

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“…An extensive chemistry has been developed for platinum(II) complexes with 2,9-dimethyl-1,10-phenanthroline (neocuproine, Neoc), showing that the presence of the two ortho methyl groups stabilizes pentacoordinate complexes by destabilizing the starting square-planar complex, [77][78][79][80][81][82][83][84][85][86][87][88][89][90][91][92][93] and a limited number of related palladium complexes have also been characterized. [78,[94][95][96][97][98][99][100] Note that in some cases the adducts are not really pentacoordinate, but one bite of neocuproine detaches to afford a complex best described as distorted square planar.…”

Section: Dimerization and Deprotonation Of Benzoic And Diphenylphosph...mentioning

confidence: 99%

Mechanistic Study of the Palladium–Phenanthroline Catalyzed Carbonylation of Nitroarenes and Amines: Palladium–Carbonyl Intermediates and Bifunctional Effects

Ragaini

Gasperini

Cenini

et al. 2009

Chemistry A European J

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Palladium-phenanthroline complexes catalyze both the nitroarene carbonylation reaction and the amine oxidative carbonylation reaction to give, depending on the conditions, carbamates and ureas. There is evidence that the key step in both processes is the amine carbonylation. Here, we show that when the reaction is run in methanol key intermediate compounds have the general formula [Pd(RPhen)(COOMe)(2)] (1) (RPhen = 1,10-phenanthroline or one of its substituted derivatives). The kinetics of the reaction of 1 with toluidine in the presence of a carboxylic or phosphorus acid is first-order with respect to complex, acid, and toluidine. A CO atmosphere is also required for the reaction to proceed. Acid dimerization was shown not to be influential under the concentration conditions examined, but reaction between the acid and toluidine is not negligible and a correction has to be applied. Diphenylphosphinic acid is more effective than any carboxylic acid in promoting this reaction, as also observed under catalytic conditions. A series of equilibria and an irreversible acid-assisted proton transfer explain the observed data. Formation of an adduct between complexes of the kind 1 and CO was spectroscopically observed when RPhen = 2,9-Me(2)Phen. Several analogous complexes were also spectroscopically characterized and the X-ray structure of [Pd(2,9-Me(2)Phen)Cl(2)(CO)] was solved. This shows an asymmetric coordination of the nitrogen ligand. Kinetic measurements were also conducted under catalytic conditions. An Eyring plot shows that the effect of the acidic promoter is to decrease the DeltaS(double dagger) value, whereas no positive effect is observed on DeltaH(double dagger). A temperature-dependent correction for the reaction between the acid and aniline and phenanthroline present under the reaction conditions has to be applied. Comparison of the results obtained under stoichiometric and catalytic conditions strongly supports the view that 1 is involved even in the latter and that the acid is acting as a bifunctional promoter.

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“…Another surprising result was a very fast CO insertion in methanol and even in H_,O observed for the complex [ (terpy)Pd(Me) ]C1 containing the terdentate :.bonded terpy ligand [161. These accelerating effects could be rationalised by a mechanism, (1996) [87][88][89][90][91][92][93][94][95][96][97][98][99][100][101][102][103] partly based on the work of Italian groups [17][18][19][20][21][22], which involves a temporary dissociation of one nitrogen donor atom of the ligand during the substitution steps of the insertion process.…”

Section: Introductionmentioning

confidence: 99%

Coordination modes of the novel bifunctional nitrogen ligands 8-(2-pyridyl)quinoline and 8-(6-methyl-2-pyridyl)quinoline towards palladium and platinum. X-ray crystal structures of (8-(2-pyridyl)quinoline)Pd(Me)Cl, (8-(2-pyridyl)quinoline)-Pd(C(O)Me)Cl and (8-(2-pyridyl)quinoline)Pd(PEt3)Cl2

Delis

Rep

Rülke

et al. 1996

Inorganica Chimica Acta

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Coordination modes of the novel bifunctional nitrogen ligands 8-(2-pyridyl)quinoline and 8-(6-methyl-2-pyridy)quinoline towards palladium and platinum. X-ray structures of (8-(2-pyridyl)quinoline)Pd(Me)Cl, (8-(2-pyridyl)quinoline)Pd(C(O)Me)Cl and (8-(2-p2 Delis, J.G.P.; Rep, M.; Rulke, R.E.; van Leeuwen, P.W.N.M.; Vrieze, K.; Fraanje, J.; Goubitz, K. Published in:Inorganica Chimica Acta DOI:10.1016/S0020-1693(96)05215-2 Link to publication Citation for published version (APA):Delis, J. G. P., Rep, M., Rulke, R. E., van Leeuwen, P. W. N. M., Vrieze, K., Fraanje, J., & Goubitz, K. (1996). Coordination modes of the novel bifunctional nitrogen ligands 8-(2-pyridyl)quinoline and 8-(6-methyl-2-pyridy)quinoline towards palladium and platinum. X-ray structures of (8-(2-pyridyl)quinoline)Pd(Me)Cl, (8-(2-pyridyl)quinoline)Pd(C(O)Me)Cl and (8-(2-p2. Inorganica Chimica Acta, 250, 87-103. DOI: 10.1016/S0020-1693(96)05215-2 General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. AbstractThe coordination chemistry of the new bidentate nitrogen ligands 8-( 2-pyridyl)quinoline (8-PQ) and 8-(6-methyl-2-pyridyl)quinotine) (Me-8-PQ) towards palladium and platinum has been studied. Several (NnN)Pd(R)C! and (NnN)Pd(alkene) complexes have been synthesised. The complex (8-PQ)Pd(Me)CI has been characterised by a single crystal X-ray determination (crystal dat;:: triclinic space group P / with a=8.513(5), b =9.338(4), c= 10.219(2) ,~, a= 108.11(2),/3=89.g2(3), 3, = 116.81 (4) °, V=680.I (6) .~3 R=0.033, Z--2). A fast CO insertion occurs into the palladium-carbon bond of the complexes ( NnN)Pd( Me)CI providing the ( N'~N)P,J(C(O) Me)C! c~omplexes. For ( 8-PQ)Pd(C(O)Me)CI an X-ray structure determination has been carried out (crysta! data: monoclinic space group P2Jc with a=9.084(4), b= 10.179(3), c= io.400(3) ~,,/3--95.59(2) °, V= 1509.2(9) A 3. R=0.043, Z=4). Unexpecied in both molecular structures is the large dihedral angle between the plane of the bidentate nitrogen ligand and the coordination plane of the palladium. Both bidentate coordinating ligands 8-PQ and Me-8-PQ show a relatively large bite angle. A monodentate coordination mode has been observed for the complexes (N'~N)M( PEh)CI2 (M = Pd, Pt), as the pyridyl group of the iigand is coordinated to the metal while the quinoline group i...

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Origin and fine tuning of the stability of five-coordinated platinum(II) and palladium(II) species. A quantum-mechanical study

Cited by 10 publications

References 14 publications

Ligand Substitution: An Assessment of the Reliability of ab Initio Calculations

Ligand Substitution: An Assessment of the Reliability of ab Initio Calculations

Mechanistic Study of the Palladium–Phenanthroline Catalyzed Carbonylation of Nitroarenes and Amines: Palladium–Carbonyl Intermediates and Bifunctional Effects

Coordination modes of the novel bifunctional nitrogen ligands 8-(2-pyridyl)quinoline and 8-(6-methyl-2-pyridyl)quinoline towards palladium and platinum. X-ray crystal structures of (8-(2-pyridyl)quinoline)Pd(Me)Cl, (8-(2-pyridyl)quinoline)-Pd(C(O)Me)Cl and (8-(2-pyridyl)quinoline)Pd(PEt3)Cl2

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