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Titolo: Assessing the stereoelectronic properties of pyrrolyl phosphines and related ligands. The quantitative analysis of ligand effects (QALE)
Autore: Fernandez, A; Reyes, C; Lee, TY; Prock, A; Giering, WP; Haar, CM; Nolan, SP;
- Indirizzi:
- Boston Univ, Metcalf Ctr Sci & Engn, Dept Chem, Boston, MA 02215 USA Boston Univ Boston MA USA 02215 i & Engn, Dept Chem, Boston, MA 02215 USA Univ New Orleans, Dept Chem, New Orleans, LA 70148 USA Univ New Orleans New Orleans LA USA 70148 Chem, New Orleans, LA 70148 USA
- Titolo Testata:
- JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2
fascicolo: 7,
,
anno: 2000,
pagine: 1349 - 1357
- SICI:
- 1470-1820(2000):7<1349:ATSPOP>2.0.ZU;2-P
- Fonte:
- ISI
- Lingua:
- ENG
- Soggetto:
- ENTHALPY-ENTROPY RELATIONSHIP; METAL-CARBONYL CLUSTERS; UNIMOLECULAR REACTION SYSTEMS; STATISTICAL-MECHANICAL MODEL; PI-ACCEPTOR CHARACTER; ISOKINETIC RELATIONSHIP; SUBSTITUTION-REACTIONS; EXPLORING STEREOSELECTIVITY; PHOSPHORUS(III) LIGANDS; L(2)FE(CO)(3) SYSTEM;
- Tipo documento:
- Article
- Natura:
- Periodico
- Settore Disciplinare:
- Physical, Chemical & Earth Sciences
- Citazioni:
- 68
- Recensione:
- Indirizzi per estratti:
- Indirizzo: Prock, A Boston Univ, Metcalf Ctr Sci & Engn, Dept Chem, Boston, MA 02215 USA Boston Univ Boston MA USA 02215 Dept Chem, Boston, MA 02215 USA
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- Citazione:
- A. Fernandez et al., "Assessing the stereoelectronic properties of pyrrolyl phosphines and related ligands. The quantitative analysis of ligand effects (QALE)", J CHEM S P2, (7), 2000, pp. 1349-1357
Abstract
By application of the QALE model (quantitative analysis of ligand effects)to the standard reduction potentials (E degrees values) and the standard enthalpies of reduction (Delta H degrees) of the eta-Cp(CO)(PZ(3))Fe(COMe)(+/0) couple (PZ(3)= a phosphorus(III) ligand), and nu(CO) for eta-Cp(CO)(PZ(3))Fe(COMe)(0), we have determined that a minimum of four parameters are necessary to describe the stereoelectronic properties of the set of ligands PPhi(Pyr)(3-i) (Pyr = pyrrolyl) and P(NC4H8)(3) (NC4H8=pyrrolidinyl). These parameters are chi(d), theta, E-ar and the pi acidity parameter, pi(p). Thevalues of these parameters were determined by linear regression analysis of a set of QALE equations. The coefficients of these equations were based on the analyses of data for PR3, PPhiR3-i, P(p-XC6H4)(3), P(OR)(3), and P(O-p-XC6H4)(3). The parameters for P(Pyr)(3) are chi(d)=31.9 +/- 0.7, theta=145 +/- 3, E-ar=3.3 +/- 0.2 and pi(p)=1.9 +/- 0.2; and for P(NC4H8)(3) the parameters are chi(d)=-1.2 +/- 1.4, theta=145 +/- 5, E-ar=-0.6 +/- 0.4 and pi(p)=0.9 +/- 0.3. P(Pyr)(3) is a poor sigma donor that possesses an E-ar parameter comparable to P(p-XC6H4)(3) and a pi acidity that is about two thirds that of P(OR)(3) and half that of P(O-p-XC6H4)(3). On the other hand, P(NC4H8)(3), which is one of the strongest sigma donor phosphorus(III) ligands, is a weak pi acid with a value for E-ar that is statistically indistinguishable from zero. PPhi(Pyr)(3-i) and P(NC4H8)(3) appear to be isosteric to P(p-XC6H4)(3).
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Documento generato il 28/01/21 alle ore 07:38:45