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Sander S, Cosgrove EJ, Müller R, Kaupp M, Braun T. Hydrogen Bonding in Platinum Indolylphosphine Polyfluorido and Fluorido Complexes. Chemistry 2023; 29:e202202768. [PMID: 36327144 PMCID: PMC10107128 DOI: 10.1002/chem.202202768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 11/02/2022] [Accepted: 11/03/2022] [Indexed: 11/06/2022]
Abstract
The reaction of the Pt complexes cis-[Pt(CH3 )(Ar){Ph2 P(Ind)}2 ] (Ind=2-(3-methyl)indolyl, Ar=4-tBuC6 H4 (1 a), 4-CH3 C6 H4 (1 b), Ph (1 c), 4-FC6 H4 (1 d), 4-ClC6 H4 (1 e), 4-CF3 C6 H4 (1 f)) with HF afforded the polyfluorido complexes trans-[Pt(F(HF)2 )(Ar){Ph2 P(Ind)}2 ] 2 a-f, which can be converted into the fluoride derivatives trans-[Pt(F)(Ar){Ph2 P(Ind)}2 ] (3 a-f) by treatment with CsF. The compounds 2 a-f and 3 a-f were characterised thoroughly by multinuclear NMR spectroscopy. The data reveal hydrogen bonding of the fluorido ligand with HF molecules and the indolylphosphine ligand. Polyfluorido complexes 2 a-f show larger |1 J(F,Pt)|, but lower 1 J(H,F) coupling constants when compared to the fluorido complexes 3 a-f. Decreasing 1 J(P,Pt) coupling constants in 2 a-f and 3 a-f suggest a cis influence of the aryl ligands in the following order: 4-tBuC6 H4 (a) ≈4-CH3 C6 H4 (b)<Ph (c)≪4-FC6 H4 (d)<4-ClC6 H4 (e)<4-CF3 C6 H4 (f). In addition, the larger cis influence of aryl ligands bearing electron-withdrawing groups in the para position correlates with decreasing magnitudes of |1 J(F,Pt)| coupling constants. The interpretation of the experimental data was supported by quantum-chemical DFT calculations.
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Affiliation(s)
- Stefan Sander
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Berlin, Germany
| | - Elizabeth J Cosgrove
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Berlin, Germany
| | - Robert Müller
- Institut für Chemie, Technische Universität Berlin, Theoretische Chemie/Quantenchemie, Sekr.C7, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Martin Kaupp
- Institut für Chemie, Technische Universität Berlin, Theoretische Chemie/Quantenchemie, Sekr.C7, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Thomas Braun
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Berlin, Germany
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Sander S, Braun T. Platinum‐Catalyzed Hydrofluorination of Alkynes: Hydrogen Bonding to Indolylphosphine Ligands to Provide Fluoride Reactivity. Angew Chem Int Ed Engl 2022; 61:e202204678. [PMID: 35420731 PMCID: PMC9401575 DOI: 10.1002/anie.202204678] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Indexed: 11/20/2022]
Abstract
The reaction of the Pt complexes cis‐[Pt(CH3)2{R2P(Ind)}2] (Ind=2‐(3‐methyl)indolyl, R=Ph (1 a), 4‐FC6H4 (1 b), 4‐CF3C6H4 (1 c)) with HF afforded the fluorido complexes trans‐[Pt(F(HF)2)(CH3){R2P(Ind)}2] 2 a–c, which can be converted into trans‐[Pt(F)(CH3){R2P(Ind)}2] (3 a–c) by treatment with CsF. Addition of 3‐hexyne to 2 a–c gave alkyne complexes trans‐[Pt(C,C‐η2‐C2H5C≡CC2H5)(CH3){R2P(Ind)}2{F(HF)2}] (4 a–c) at which a fluoride is stabilised as polyfluoride in the coordination sphere by hydrogen bonding to the indolyl‐substituted phosphine ligands. Subsequent heating of a solution of 4 a in the presence of PVPHF led to fluoroalkene formation. Selective catalytic hydrofluorination of alkynes to yield (Z)‐fluoroalkenes were developed. The ability of hydrogen bonding to polyfluoride favours the fluorination step as demonstrated by studies with complexes bearing no indolyl groups at the phosphine ligands.
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Affiliation(s)
- Stefan Sander
- Department of Chemistry Humboldt Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Thomas Braun
- Department of Chemistry Humboldt Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
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3
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Sander S, Braun T. Platinum‐Catalyzed Hydrofluorination of Alkynes: Hydrogen Bonding to Indolylphosphine Ligands to Provide Fluoride Reactivity. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202204678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Stefan Sander
- Humboldt-Universität zu Berlin: Humboldt-Universitat zu Berlin chemistry GERMANY
| | - Thomas Braun
- Humboldt University Chemistry Brook-Taylor Str. 2 12489 Berlin GERMANY
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Kraka E, Freindorf M. Characterizing the Metal–Ligand Bond Strength via Vibrational Spectroscopy: The Metal–Ligand Electronic Parameter (MLEP). TOP ORGANOMETAL CHEM 2020. [DOI: 10.1007/3418_2020_48] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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5
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Baquero EA, Rodríguez-Zúñiga A, Flores JC, Temprado M, de Jesús E. Revisiting the synthesis of trans-[Pt(dmso)2ClMe] and cis-[Pt(dmso)2Me2]: Experimental and DFT studies. J Organomet Chem 2019. [DOI: 10.1016/j.jorganchem.2019.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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6
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Cremer D, Kraka E. Generalization of the Tolman electronic parameter: the metal–ligand electronic parameter and the intrinsic strength of the metal–ligand bond. Dalton Trans 2017; 46:8323-8338. [DOI: 10.1039/c7dt00178a] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The MLEP is a new, generally applicable measure of the metal–ligand bond strength based on vibrational spectroscopy, replacing the TEP.
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Affiliation(s)
- Dieter Cremer
- Computational and Theoretical Chemistry Group (CATCO)
- Department of Chemistry
- Southern Methodist University
- Dallas
- USA
| | - Elfi Kraka
- Computational and Theoretical Chemistry Group (CATCO)
- Department of Chemistry
- Southern Methodist University
- Dallas
- USA
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Edouard GA, Kelley P, Herbert DE, Agapie T. Aryl Ether Cleavage by Group 9 and 10 Transition Metals: Stoichiometric Studies of Selectivity and Mechanism. Organometallics 2015. [DOI: 10.1021/acs.organomet.5b00710] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Guy A. Edouard
- Division
of Chemistry and
Chemical Engineering, California Institute of Technology, 1200 East
California Boulevard MC 127-72, Pasadena, California 91125, United States
| | - Paul Kelley
- Division
of Chemistry and
Chemical Engineering, California Institute of Technology, 1200 East
California Boulevard MC 127-72, Pasadena, California 91125, United States
| | - David E. Herbert
- Division
of Chemistry and
Chemical Engineering, California Institute of Technology, 1200 East
California Boulevard MC 127-72, Pasadena, California 91125, United States
| | - Theodor Agapie
- Division
of Chemistry and
Chemical Engineering, California Institute of Technology, 1200 East
California Boulevard MC 127-72, Pasadena, California 91125, United States
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Campos J, Ortega-Moreno L, Conejero S, Peloso R, López-Serrano J, Maya C, Carmona E. Reactivity of Cationic Agostic and Carbene Structures Derived from Platinum(II) Metallacycles. Chemistry 2015; 21:8883-96. [DOI: 10.1002/chem.201500756] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Indexed: 11/11/2022]
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Ortuño MA, Conejero S, Lledós A. True and masked three-coordinate T-shaped platinum(II) intermediates. Beilstein J Org Chem 2013; 9:1352-82. [PMID: 23946831 PMCID: PMC3740817 DOI: 10.3762/bjoc.9.153] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 06/10/2013] [Indexed: 11/23/2022] Open
Abstract
Although four-coordinate square-planar geometries, with a formally 16-electron counting, are absolutely dominant in isolated Pt(II) complexes, three-coordinate, 14-electron Pt(II) complexes are believed to be key intermediates in a number of platinum-mediated organometallic transformations. Although very few authenticated three-coordinate Pt(II) complexes have been characterized, a much larger number of complexes can be described as operationally three-coordinate in a kinetic sense. In these compounds, which we have called masked T-shaped complexes, the fourth position is occupied by a very weak ligand (agostic bond, solvent molecule or counteranion), which can be easily displaced. This review summarizes the structural features of the true and masked T-shaped Pt(II) complexes reported so far and describes synthetic strategies employed for their formation. Moreover, recent experimental and theoretical reports are analyzed, which suggest the involvement of such intermediates in reaction mechanisms, particularly C-H bond-activation processes.
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Affiliation(s)
- Manuel A Ortuño
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain
| | - Salvador Conejero
- Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica, CSIC and Universidad de Sevilla, Avda. Américo Vespucio 49, 41092 Sevilla, Spain
| | - Agustí Lledós
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain
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Hosseini FN, Nabavizadeh SM. Application of variable-temperature kinetic experiments to oxidative addition reactions of dimethylplatinum(II) complexes with alkyl halides. TRANSIT METAL CHEM 2013. [DOI: 10.1007/s11243-013-9739-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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11
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Guido E, D’Amico G, Russo N, Sicilia E, Rizzato S, Albinati A, Romeo A, Plutino MR, Romeo R. Mechanistic Insight into Protonolysis and Cis−Trans Isomerization of Benzylplatinum(II) Complexes Assisted by Weak Ligand-to-Metal Interactions. A Combined Kinetic and DFT Study. Inorg Chem 2011; 50:2224-39. [DOI: 10.1021/ic101879s] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Emanuela Guido
- Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Università di Messina, Viale F. Stagno D'Alcontres 31, Vill. S. Agata, I-98166 Messina, Italy
| | - Giuseppina D’Amico
- Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Università di Messina, Viale F. Stagno D'Alcontres 31, Vill. S. Agata, I-98166 Messina, Italy
| | - Nino Russo
- Dipartimento di Chimica, Università della Calabria, I-87030 Arcavacata di Rende (Cs), Italy
| | - Emilia Sicilia
- Dipartimento di Chimica, Università della Calabria, I-87030 Arcavacata di Rende (Cs), Italy
| | - Silvia Rizzato
- Dipartimento di Chimica Strutturale e Facoltà di Farmacia, via Venezian 21, Università di Milano, Milano, Italy
| | - Alberto Albinati
- Dipartimento di Chimica Strutturale e Facoltà di Farmacia, via Venezian 21, Università di Milano, Milano, Italy
| | - Andrea Romeo
- Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Università di Messina, Viale F. Stagno D'Alcontres 31, Vill. S. Agata, I-98166 Messina, Italy
| | - M. Rosaria Plutino
- Istituto per lo Studio dei Materiali Nanostrutturati, ISMN-CNR, Unità di Messina-Sezione di Palermo, c/o Dip. di Chim. Inorg., Chim. Anal., Chim. Fis., Università di Messina, Viale F. Stagno D'Alcontres 31, Vill. S. Agata, I-98166 Messina, Italy
| | - Raffaello Romeo
- Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Università di Messina, Viale F. Stagno D'Alcontres 31, Vill. S. Agata, I-98166 Messina, Italy
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13
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Alibrandi G, Lo Vecchio C, Villari A, Villari I. Molecular apparatus for automatic titrations. Chemistry 2010; 16:7700-3. [PMID: 20533470 DOI: 10.1002/chem.201000965] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Giuseppe Alibrandi
- Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica-Facoltà di Scienze Matematiche, Fisiche e Naturali, Università di Messina-Salita Sperone 31, Villaggio S. Agata, 98166 Messina, Italy.
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14
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Cornacchia D, Pellicani RZ, Intini FP, Pacifico C, Natile G. Solution behavior of amidine complexes: an unexpected cis/trans isomerization and formation of di- and trinuclear platinum(III) and platinum(II) species. Inorg Chem 2010; 48:10800-10. [PMID: 19821556 DOI: 10.1021/ic9011372] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Platinum bis-amidine complexes (both the cis and trans isomers) are stable in acetone and chlorinated solvents but are unstable in protic solvents such as methanol or water. In the latter solvents an initial cis/trans isomerization leads to formation of an equilibrium mixture with a cis/trans ratio of about 1:4; subsequently a dinuclear platinum(III) complex (1) is formed under aerobic conditions while, under anaerobic conditions, a trinuclear platinum(II) compound (2) is obtained. We hypothesize that the process of isomerization and formation of polynuclear compounds (1 and 2) have a common precursor: a dinuclear platinum(II) species supported by two bridging amidinato ligands (3), formed in small yield, which can either dissociate back to monomers of cis/trans configuration or evolve in two different polynuclear species depending upon the aerobic/anaerobic conditions. In aerobic conditions, oxidation of platinum(II) to platinum(III) together with formation of two additional amidinato bridges across the two platinum centers takes place leading to compound 1. In contrast, in anaerobic conditions, oxidation of platinum is prevented and the dinuclear platinum(II) precursor remains in solution until it reacts with an extra molecule of the starting mononuclear complex which loses its two amidine ligands and cross-links the two bridging amidinato ligands of 3 to yield compound 2. This latter features two triply bridging amidinato ligands linking the three platinum units to form a pocket. Complexes 1 and 2 have been characterized by means of IR and NMR spectroscopy, mass spectrometry, elemental analysis, and X-ray crystallography.
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Affiliation(s)
- Daniele Cornacchia
- Università degli Studi di Bari, Dipartimento Farmaco-Chimico, via E. Orabona 4, 70125 Bari, Italy
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15
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Braddock-Wilking J, Gao LB, Rath NP. Luminescent platinum complexes containing phosphorus-linked silole ligands. Dalton Trans 2010; 39:9321-8. [DOI: 10.1039/c0dt00259c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Alibrandi G, Lister DG, Lo Vecchio C. Towards molecular temperature programmers for variable-temperature kinetic experiments. Chemphyschem 2009; 10:3209-11. [PMID: 19830770 DOI: 10.1002/cphc.200900712] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Giuseppe Alibrandi
- Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Università di Messina, Salita Sperone 31, Villaggio S. Agata, 98166 Messina, Italy.
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17
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Alibrandi G, Lo Vecchio C, Lando G. [1.1.1]Cryptand: A Molecular Automatic Titrator. Angew Chem Int Ed Engl 2009; 48:6332-4. [DOI: 10.1002/anie.200902599] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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18
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Alibrandi G, Lo Vecchio C, Lando G. [1.1.1]Cryptand: A Molecular Automatic Titrator. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200902599] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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19
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Kakeya M, Tanabe M, Nakamura Y, Osakada K. Dialkyl- and diaryl-platinum(II) complexes with secondary phosphines: Preparation, structure and thermal reaction giving the metallopolymer. J Organomet Chem 2009. [DOI: 10.1016/j.jorganchem.2009.03.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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20
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Bennett MA, Bhargava SK, Privér SH, Willis AC. Selective Cleavage by Acids of One Metal–Carbon σ‐Bond of a Bis(ortho‐platinated) Triarylphosphane: A31P NMRtrans‐Influence Series Based on the Unit Pt(κ2‐C6H3‐5‐Me‐2‐PPh2)(PPh2‐4‐tol). Eur J Inorg Chem 2008. [DOI: 10.1002/ejic.200800333] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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21
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Alibrandi G. Cryptand 111: A Chemical Device for Variable-pH Kinetic Experiments. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200800180] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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22
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Alibrandi G. Cryptand 111: A Chemical Device for Variable-pH Kinetic Experiments. Angew Chem Int Ed Engl 2008; 47:3026-8. [DOI: 10.1002/anie.200800180] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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23
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Cornacchia D, Cerasino L, Pacifico C, Natile G. Platinum(II) Complexes with the Diethyl Aminomethylphosphonate Ligand (amp): Characterization, Properties, and Unusual Solution Behavior. Eur J Inorg Chem 2008. [DOI: 10.1002/ejic.200701245] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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24
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Romeo R, Carnabuci S, Fenech L, Plutino MR, Albinati A. Overcrowded Organometallic Platinum(II) Complexes That Behave as Molecular Gears. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200600827] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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25
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Romeo R, Carnabuci S, Fenech L, Plutino MR, Albinati A. Overcrowded Organometallic Platinum(II) Complexes That Behave as Molecular Gears. Angew Chem Int Ed Engl 2006; 45:4494-8. [PMID: 16770825 DOI: 10.1002/anie.200600827] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Raffaello Romeo
- Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Università di Messina, Salita Sperone 31, 98166 Vill. S. Agata, Messina, Italy.
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26
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Karshtedt D, McBee JL, Bell AT, Tilley TD. Stoichiometric and Catalytic Arene Activations by Platinum Complexes Containing Bidentate Monoanionic Nitrogen-Based Ligands. Organometallics 2006. [DOI: 10.1021/om0600902] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dmitry Karshtedt
- Departments of Chemistry and Chemical Engineering, University of California, Berkeley, Berkeley, California 94720, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720
| | - Jennifer L. McBee
- Departments of Chemistry and Chemical Engineering, University of California, Berkeley, Berkeley, California 94720, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720
| | - Alexis T. Bell
- Departments of Chemistry and Chemical Engineering, University of California, Berkeley, Berkeley, California 94720, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720
| | - T. Don Tilley
- Departments of Chemistry and Chemical Engineering, University of California, Berkeley, Berkeley, California 94720, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720
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27
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Fanizzi F, Margiotta N, Lanfranchi M, Tiripicchio A, Pacchioni G, Natile G. A Molecular Tool for Measuring the Electron-Acceptor Ability of Ligands from Crystallographic Data. Eur J Inorg Chem 2004. [DOI: 10.1002/ejic.200300888] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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28
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Thomas CM, Peters JC. Coordinating Anions: (Phosphino)tetraphenylborate Ligands as New Reagents for Synthesis. Inorg Chem 2003; 43:8-10. [PMID: 14704047 DOI: 10.1021/ic0350234] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Anionic, electron-releasing phosphines that incorporate a borate counteranion within the ligand framework are promising reagents for organometallic catalysis. This report describes the synthesis of a new class of monodentate tertiary phosphines built upon the commonly employed tetraphenylborate anion. These new phosphines are highly stable and strongly electron-releasing and readily coordinate transition metals. Moreover, they are promising reagents for catalysis, as demonstrated by their ability to promote the Suzuki cross-coupling of aryl chloride substrates.
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Affiliation(s)
- Christine M Thomas
- Division of Chemistry and Chemical Engineering, Arnold and Mabel Beckman Laboratories of Chemical Synthesis, California Institute of Technology, Pasadena California 91125, USA
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Giering WP, Prock A, Fernandez AL. Comments on the Electrostatic Minimum Potential (Vmin) as a Measure of the Electron-Donating Power of PZ3. Inorg Chem 2003; 42:8033-7. [PMID: 14632523 DOI: 10.1021/ic034223c] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In a recent publication, Suresh and Koga suggested that the molecular electrostatic potential minimum (V(min)) could be used as a quantitative measure of the "sigma donating power" of substituted phosphorus(III) ligands. In support of this assertion, they showed linear correlations between a number of physicochemical properties and V(min). Our examination of the analyses of the sets of experimental data used to support this assertion shows unequivocally that the variations in the properties cannot be described by a single parameter. Therefore, the utility of V(min) as a measure of the "sigma donating power" of substituted phosphorus(III) ligands remains unsubstantiated.
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Affiliation(s)
- Warren P Giering
- Department of Chemistry, Metcalf Science and Engineering Center, Boston University, Boston, Massachusetts 02215, USA
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30
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Alibrandi G, D'Aliberti S, Tresoldi G. Spectrophotometric variable-concentration kinetic experiments applied to inorganic reactions. INT J CHEM KINET 2003. [DOI: 10.1002/kin.10150] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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31
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Alibrandi G, Coppolino S, D'Aliberti S, Ficarra R, Micali N, Villari A. Fast drug stability determination by LC variable-parameter kinetic experiments. J Pharm Biomed Anal 2003; 32:1073-9. [PMID: 12899996 DOI: 10.1016/s0731-7085(03)00211-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Variable-parameter kinetic experiments were carried out using HPLC as analytical instrument. The hydrolysis of aspirin was followed both at variable-temperature and at variable-pH conditions. The peak areas relative to salicylic acid were processed by direct fit to a mathematical model and/or by differential method obtaining, by single experiments, the values of the apparent rate constant in the whole range of temperature and pH studied. The results, although the discontinuity of this kind of analysis, are in agreement with those obtained by constant-parameter kinetics but saving experimental time.
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Affiliation(s)
- Giuseppe Alibrandi
- Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Università di Messina, Salita Sperone 31, Villaggio S. Agata, 98166 Messina, Italy.
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Alibrandi G, Coppolino S, D'Aliberti S, Ficarra P, Micali N, Villari A. Variable-ionic strength kinetic experiments in drug stability studies. J Pharm Sci 2003; 92:1730-3. [PMID: 12884259 DOI: 10.1002/jps.10422] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The dependence of the pseudo-first-order rate constant on the ionic strength for the alkaline hydrolysis of indomethacin has been obtained, for the first time, in a single kinetic experiment carried out by varying with time the salt concentration inside the reaction vessel. The kinetic profile obtained was processed using as a mathematical model the variable-parameter kinetic equation containing the Bronsted-Bjerrum equation as the dependence function. The results are in good agreement with those obtained by the traditional method but the experimental time is reduced to about one-tenth.
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Affiliation(s)
- Giuseppe Alibrandi
- Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Università di Messina, Salita Sperone 31, Vill S Agata, 98166 Messina, Italy.
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Romeo R, Monsù Scolaro L, Plutino MR, Fabrizi de Biani F, Bottari G, Romeo A. Ligand exchange and substitution at platinum(II) complexes: evidence for a dissociative mechanism. Inorganica Chim Acta 2003. [DOI: 10.1016/s0020-1693(02)01505-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Reyes C, Prock A, Giering WP. Analysis of the enantioselectivities and initial rates of the hydrosilylation of acetophenone catalyzed by [Rh(cod)Cl]2/(chiral diphosphine). The quantitative analysis of ligand effects. J Organomet Chem 2003. [DOI: 10.1016/s0022-328x(02)02221-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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35
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Lucey DW, Helfer DS, Atwood JD. Stability of Methyl Platinum Complexes in Water: The Role of pH and Geometry. Organometallics 2003. [DOI: 10.1021/om020699c] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Derrick W. Lucey
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260
| | - Derrik S. Helfer
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260
| | - Jim D. Atwood
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260
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Stulz E, Maue M, Feeder N, Teat SJ, Ng YF, Bond AD, Darling SL, Sanders JKM. Phosphine and phosphonite complexes of a ruthenium(II) porphyrin. 1. Synthesis, structure, and solution state studies. Inorg Chem 2002; 41:5255-68. [PMID: 12354060 DOI: 10.1021/ic025727y] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have investigated the effect of complexation of different phosphorus ligands on the stability, solid state structure, and spectroscopic properties (NMR, IR, UV-vis) of a 5,15-diphenyl-substituted ruthenium porphyrin, (MeOH)Ru(II)(CO)(DPP) 2 [DPP = 5,15-bis(3',5'-di-tert-butyl)phenyl-2,8,12,18-tetraethyl-3,7,13,17-tetramethylporphyrin]. The ligands used are PPh(3), diphenyl(phenylacetenyl)phosphine (DPAP), bis(diphenylphosphino)acetylene (DPPA), tris(phenylacetenyl)phosphine [(PA)(3)P], and diethyl (phenylacetenyl)phosphonite [PAP(OEt)(2)]. The mono-phosphine complexes (PR(3))Ru(II)(CO)(DPP) are readily formed in solution in quantitative yields. The complexes display association constants ranging from 1.2 x 10(4) M(-1) for PPh(3) to 4.8 x 10(6) M(-1) for PAP(OEt)(2). The weak association of PPh(3) does not correlate with its pK(a), delta((31)P), or cone angle value and is attributed to steric effects. Due to their kinetic lability, which is shown by 2D NMR spectroscopy, and the weakening of the carbonyl ligand via a trans effect, the mono-phosphine complexes could not be isolated. IR spectroscopy gives the relative order of pi-acceptor strength as PPh(3) < DPAP, DPPA < (PA)(3)P < PAP(OEt)(2), whereas the relative order of the sigma-donor strength is PPh(3) < (PA)(3)P < DPAP, DPPA < PAP(OEt)(2), based on the calculated pK(a) values and on the (31)P((1)H) NMR chemical shifts of the ligands. The chemical shift differences in the (31)P9(1)H)) NMR spectra upon ligand binding display a linear correlation with the calculated pK(a) values of the protonated ligands HPR(3)(+); we propose that the pK(a), and probably other electronic properties, of a specific phosphorus ligand can be estimated on the basis of the chemical shift difference Deltadelta((31)P) upon complexation to a metalloporphyrin. The bis-phosphine complexes can be isolated in pure form by crystallization from CHCl(3)-MeOH solutions using excess ligand. Association of the second ligand is in the same order of magnitude as the first binding for the phosphines, but the second phosphonite binding is decreased by a factor of about 100. The solid state structures show only marginal differences in the geometrical parameters. The calculated and the crystallographic cone angles of the ligands generally do not match, apart from the values obtained for PAP(OEt)(2).
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Affiliation(s)
- Eugen Stulz
- University Chemical Laboratory, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K.
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37
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Alibrandi G, Coppolino S, D'Aliberti S, Ficarra P, Micali N, Villari A. Temperature-rate profiles by polarimetric variable-temperature kinetic experiments to study racemization reactions. J Pharm Biomed Anal 2002; 29:1025-9. [PMID: 12110387 DOI: 10.1016/s0731-7085(02)00143-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The racemization of (-)-adrenaline was followed by polarimetric variable-temperature kinetic experiments obtaining activation parameters and k(obs)(T) profile in one tenth of the time usually spent for traditional kinetic runs. A polarimeter connected to a computer for the acquisition and processing of the analytical data was used. The kinetic profiles were processed by both an integral method and a differential method. The results are in good agreement with each other and with those obtained by constant-temperature kinetics.
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Affiliation(s)
- Giuseppe Alibrandi
- Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Università di Messina, Salita Sperone 31, Villaggio S. Agata, Messina, Italy.
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Clegg W, Eastham GR, Elsegood MRJ, Heaton BT, Iggo JA, Tooze RP, Whyman R, Zacchini S. Characterization and Dynamics of [Pd(L−L)H(solv)]+, [Pd(L−L)(CH2CH3)]+, and [Pd(L−L)(C(O)Et)(THF)]+ (L−L = 1,2-(CH2PBut2)2C6H4): Key Intermediates in the Catalytic Methoxycarbonylation of Ethene to Methylpropanoate. Organometallics 2002. [DOI: 10.1021/om010938g] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- William Clegg
- Chemistry Department, University of Newcastle, Newcastle-upon-Tyne, U.K. NE1 7RU, Ineos Acrylics, PO Box 90, Wilton, Middlesborough, Cleveland, U.K. TS90 8JE, and Chemistry Department, University of Liverpool, Liverpool, U.K. L69 7ZD
| | - Graham R. Eastham
- Chemistry Department, University of Newcastle, Newcastle-upon-Tyne, U.K. NE1 7RU, Ineos Acrylics, PO Box 90, Wilton, Middlesborough, Cleveland, U.K. TS90 8JE, and Chemistry Department, University of Liverpool, Liverpool, U.K. L69 7ZD
| | - Mark R. J. Elsegood
- Chemistry Department, University of Newcastle, Newcastle-upon-Tyne, U.K. NE1 7RU, Ineos Acrylics, PO Box 90, Wilton, Middlesborough, Cleveland, U.K. TS90 8JE, and Chemistry Department, University of Liverpool, Liverpool, U.K. L69 7ZD
| | - Brian T. Heaton
- Chemistry Department, University of Newcastle, Newcastle-upon-Tyne, U.K. NE1 7RU, Ineos Acrylics, PO Box 90, Wilton, Middlesborough, Cleveland, U.K. TS90 8JE, and Chemistry Department, University of Liverpool, Liverpool, U.K. L69 7ZD
| | - Jonathan A. Iggo
- Chemistry Department, University of Newcastle, Newcastle-upon-Tyne, U.K. NE1 7RU, Ineos Acrylics, PO Box 90, Wilton, Middlesborough, Cleveland, U.K. TS90 8JE, and Chemistry Department, University of Liverpool, Liverpool, U.K. L69 7ZD
| | - Robert P. Tooze
- Chemistry Department, University of Newcastle, Newcastle-upon-Tyne, U.K. NE1 7RU, Ineos Acrylics, PO Box 90, Wilton, Middlesborough, Cleveland, U.K. TS90 8JE, and Chemistry Department, University of Liverpool, Liverpool, U.K. L69 7ZD
| | - Robin Whyman
- Chemistry Department, University of Newcastle, Newcastle-upon-Tyne, U.K. NE1 7RU, Ineos Acrylics, PO Box 90, Wilton, Middlesborough, Cleveland, U.K. TS90 8JE, and Chemistry Department, University of Liverpool, Liverpool, U.K. L69 7ZD
| | - Stefano Zacchini
- Chemistry Department, University of Newcastle, Newcastle-upon-Tyne, U.K. NE1 7RU, Ineos Acrylics, PO Box 90, Wilton, Middlesborough, Cleveland, U.K. TS90 8JE, and Chemistry Department, University of Liverpool, Liverpool, U.K. L69 7ZD
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Mann BE, Guzman MH. Dissolution of [RhCl(PPh3)3] in the ionic liquid, 1-ethyl-3-methyl imidazolium chloroaluminate(III), and its reaction with H2. The stabilization of Rh(I) species in an ionic liquid. Inorganica Chim Acta 2002. [DOI: 10.1016/s0020-1693(01)00712-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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40
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Romeo R, Fenech L, Scolaro LM, Albinati A, Macchioni A, Zuccaccia C. Fluxional behavior of the dinitrogen ligand 2,9-dimethyl-1,10-phenanthroline in cationic methyl platinum(II) complexes. Inorg Chem 2001; 40:3293-302. [PMID: 11421672 DOI: 10.1021/ic0014080] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ionic methylplatinum(II) complexes [Pt(Me)(L)(dmphen)]X (dmphen = 2,9-dimethyl-1,10-phenanthroline, L = Me(2)SO, X = PF(6)(-) 1a, BF(4)(-) 1b, CF(3)SO(3)(-) 1c, ClO(4)(-) 1d, B(C(6)H(5))(4)(-) 1e, [B(3,5-(CF(3))(2)C(6)H(3))(4)](-) 1f; L = n-Bu(2)SO, X = CF(3)SO(3)(-) 1g; L = PPh(3), X = PF(6)(-) 2a, BF(4)(-) 2b, CF(3)SO(3)(-) 2c, ClO(4)(-) 2d, B(C(6)H(5))(4)(-) 2e, [B(3,5-(CF(3))(2)C(6)H(3))(4)](-) 2f; X = CF(3)SO(3)(-), L = CyNH(2) 3a, i-PrNH(2) 3b, 2,6-Me(2)py 3c, EtNH(2) 3d, AsPh(3) 3e, dimethylthiourea (Me(2)th) 3f and the uncharged [Pt(Me)(X)(dmphen)] (X = SCN(-) 4a, SeCN(-) 4b) complexes have been synthesized and fully characterized. In chloroform, as well as in acetone or methanol, complexes 1a-1g, 2a-2h (X = Cl(-) g, NO(2)(-) h, formed "in situ"), and 3e show dynamic behavior due to the oscillation of the symmetric chelating ligand dmphen between nonequivalent bidentate modes. All the other compounds feature a static structure in solution. The crystal structure of 2a shows a tetrahedral distortion of the square planar coordination geometry, a loss of planarity of the dmphen ligand, and, most notably, a rotation of the dmphen moiety, around the N1-N2 vector, to form a dihedral angle of 42.64(8) degrees with the mean coordination plane. The hexafluorophosphate ion lies on the side of the phenanthroline ligand. The interionic structures of 2a, 2b, and 2f were investigated in CDCl(3) at low temperature by (1)H-NOESY and (19)F[(1)H]-HOESY NMR spectroscopies. Whereas PF(6)(-) (2a) and BF(4)(-) (2b) show strong contacts with the cation [Pt(Me)(PPh(3))(dmphen)](+), being located preferentially on the side of the phenanthroline ligand, the [B(3,5-(CF(3))(2)C(6)H(3))(4)](-) (2f) ion does not form a tight ion pair. The dynamic process was studied by variable-temperature NMR spectroscopy for 1a-1f and 2a-2h in CDCl(3). The activation energies DeltaG(298) for the sulfoxide complexes 1a-1f are lower than those of the corresponding phosphine complexes 2a-2f by approximately 10 kJ mol(-)(1). The nature of the counteranion exerts a tangible influence on the fluxionality of dmphen in both series of complexes 1 and 2. The sequence of energies observed for 2a-2h encompasses an overall difference of about 16 kJ mol(-)(1), increasing in the order Cl(-) approximately NO(2)(-) << CF(3)SO(3)(-) < ClO(4)(-) < B(C(6)H(5))(4)(-) < BF(4)(-) approximately PF(6)(-) < B(3,5-(CF(3))(2)C(6)H(3))(4)(-). Acetone and methanol have an accelerating effect on the flipping. Concentration-dependent measurements, carried out in CDCl(3) for 2a with n-Bu(4)NPF(6) and the ligands dmphen, n-Bu(2)SO, sec-Bu(2)SO, and sec-Bu(2)S showed that the rate of the fluxional motion is unaffected by added n-Bu(4)NPF(6), whereas in the other cases this increases linearly with increasing ligand concentration, according to a pattern of behavior typical of substitution reactions. Dissociative and associative mechanisms can be envisaged for the observed process of flipping. Dissociation can be prevalent within the ion pair formed by a "noncoordinating" anion with the metallic cationic complex in chloroform. Among the possible associative mechanisms, promoted by polar solvents or by relatively strong nucleophiles, a consecutive displacement mechanism is preferred to intramolecular rearrangements of five-coordinate intermediates.
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Affiliation(s)
- R Romeo
- Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica and Istituto di Chimica e Tecnologia dei Prodotti Naturali (ICTPN-CNR), Sezione di Messina, Università di Messina, Salita Sperone 31, Vill. S. Agata, 98166 Messina, Italy
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Abstract
The complete pH-rate profile of the hydrolysis reaction of aspirin, requiring many experiments in the past, was obtained by a single variable-parameter kinetic experiment carried out by varying the hydrogen ion concentration. The experiment was carried out spectrophotometrically, reading automatically absorbance, pH, and temperature inside the reaction vessel. The results obtained by the fast processing of the kinetic profile are identical to those obtained under the same conditions but using traditional constant-pH kinetic runs. This method provides the possibility of reducing the amount of time and chemicals usually spent in collecting kinetic data in such mechanistic studies by nearly two orders of magnitude.
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Affiliation(s)
- G Alibrandi
- Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Università di Messina, Salita Sperone 31, Villaggio S. Agata, 98166 Messina, Italy.
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Romeo R, Plutino MR, Monsù Scolaro L, Stoccoro S, Minghetti G. Role of cyclometalation in controlling the rates of ligand substitution at platinum(II) complexes. Inorg Chem 2000; 39:4749-55. [PMID: 11196950 DOI: 10.1021/ic0004479] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The rates of chloride for triphenylphosphine substitution have been measured in dichloromethane for a series of cyclometalated [Pt(N-N-C)Cl] complexes containing a number of terdentate N-N-C anionic ligands, derived from deprotonated alkyl-, phenyl-, and benzyl-6-substituted 2,2'-bipyridines. These rates have been compared with those of the corresponding [Pt(N-N)(C)Cl] (N-N = 2,2'-bipyridine; C = CH3 or C6H5) complexes having the same set of donor atoms but less constrained arrangements of the ligands. The reactions of the cyclometalated compounds occur as a single-stage conversion from the substrate to the ionic pair [Pt(N-N-C)(PPh3)]Cl products. There is no evidence by 1H and 31P(1H) NMR spectroscopy for the formation of other Pt(II) species or of concurrent ring-opening processes. In contrast, in the monoalkyl- or monoaryl-2,2'-bipyridine complexes, chloride substitution is followed by subsequent slower processes which involve the detachment of one arm of the chelated 2,2'-bipyridine, fast cis to trans isomerization of the cis-[Pt(PPh3)2(eta 1-bipy)(R)]+ transient intermediate, and, eventually, the release of free bipy, yielding trans-[Pt(PPh3)2(R)Cl] (R = Me or Ph). All reactions are first-order with respect to complex and phosphine concentration, obeying the simple rate law kobsd = k2[PPh3]. The values of the second-order rate constant k2 do not seem particularly sensitive to the nature of the bonded organic moiety (alkyl or aryl), to its structure (cyclometalated or not), to the size of the ring, or to the number of alkyl substituents on it. The effects are those foreseen on the basis of an associative mode of activation. The only exception to this pattern of behavior is constituted by the complex [Pt(bipy phi-H)Cl] (bipy phi = 6-phenyl-2,2'-bipyridine), which features a significant rate enhancement with respect to the analogue [Pt(bipy)(Ph)Cl] complex. The results of this work, together with those of a previous paper, suggest that there is not a specific role of cyclometalation in controlling the reactivity, unless an in-plane aryl ring becomes part of the pi-acceptor system of the chelated 2,2-bipyridine, behaving as a cyclometalated analogue of the nitrogen terdentate 2,2':6',2"-terpyridine.
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Affiliation(s)
- R Romeo
- Dipartimento di Chimica Inorganica, Fisica e Istituto di Chimica e Tecnologia dei Prodotti Naturali (ICTPN-CNR), Università di Messina, Salita Sperone 31, Vill. S. Agata, 98166 Messina, Italy.
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Woska D, Prock A, Giering WP. Determination of the Stereoelectronic Parameters of PF3, PCl3, PH3, and P(CH2CH2CN)3. The Quantitative Analysis of Ligand Effects (QALE). Organometallics 2000. [DOI: 10.1021/om0004850] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- David Woska
- Department of Chemistry, Metcalf Science and Engineering Center, Boston University, Boston, Massachusetts 02215
| | - Alfred Prock
- Department of Chemistry, Metcalf Science and Engineering Center, Boston University, Boston, Massachusetts 02215
| | - Warren P. Giering
- Department of Chemistry, Metcalf Science and Engineering Center, Boston University, Boston, Massachusetts 02215
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Plutino MR, Scolaro LM, Romeo R, Grassi A. To what extent can cyclometalation promote associative or dissociative ligand substitution at platinum(II) complexes? A combined kinetic and theoretical approach. Inorg Chem 2000; 39:2712-20. [PMID: 11232805 DOI: 10.1021/ic9914894] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ligand exchange rate constants for the reactions [Pt(bph)(SR2)2] + 2*SR2 --> [Pt(bph)(*SR2)2] + 2SR2 (bph = 2,2'-biphenyl dianion; R = Me and Et) and cis-[PtPh2(SMe2)2] + 2*SMe2 --> cis-[PtPh2(*SMe2)2] + 2SMe2 have been determined in CDCl3 as a function of ligand concentration and temperature, by 1H NMR isotopic labeling and magnetization transfer experiments. The rates of exchange show no dependence on ligand concentration and the kinetics are characterized by largely positive entropies of activation. The kinetics of displacement of the thioethers from [Pt(bph)(SR2)2] with the dinitrogen ligands 2,2'-bipyridine and 1,10-phenanthroline (N-N) to yield [Pt(bph)(N-N)], carried out in the presence of sufficient excess of thioether and N-N to ensure pseudo-first-order conditions, follow a nonlinear rate law k(obsd) = a[N-N]/(b[SR2] + [N-N]). The general pattern of behavior indicates that the rate-determining step for substitution is the dissociation of a thioether ligand and the formation of a three-coordinated [Pt(bph)(SR2)] intermediate. The value of the parameter a, which measures the rate of ligand dissociation, is constant and independent of the nature of N-N, and it is in reasonable agreement with the value of the rate of ligand exchange at the same temperature. Theoretical ab initio calculations were performed for both [Pt(bph)(SMe2)2] and cis-[PtPh2(SMe2)2], and for their three-coordinated derivatives upon the loss of one SMe2 ligand. The latter optimize in a T-shaped structure. Calculations were performed in the HF approximation (LANL2DZ basis set) and refined by introducing the correlation terms (Becke3LYP model). The activation enthalpies from the optimized vacuum-phase geometries are 52.3 and 72.2 kJ moll compared to the experimental values in CDCl3 solution, 80 +/- 1 and 93 +/- 1 kJ mol(-1) for [Pt(bph)(SMe2)2] and cis-[PtPh2(SMe2)2], respectively. The electrostatic potential maps of both parent compounds show a remarkable concentration of negative charge over the platinum atom which exerts a repulsion force on an axially incoming nucleophile. On the other hand, the strength of the organic carbanions trans to the leaving group and the stabilization of the T-shaped intermediate in the singlet ground state may also rationalize the preference for the dissociative mechanism. All of the kinetic and theoretical data support the latter hypothesis and indicate, in particular, that dissociation from the complex containing the planar 2,2'-biphenyl dianion is easier than from its analogue with single aryl ligands. Electron back-donation from filled d orbitals of the metal to empty pi* of the in-plane cyclometalated rings is weak or absent and is not operative in promoting an associative mode of activation.
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Affiliation(s)
- M R Plutino
- Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica e Istituto di Chimica e Tecnologia dei Prodotti Naturali, Università di Messina, Italy
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Haar CM, Nolan SP. Solution thermochemical study of ligand substitution reactions of hybrid alkyl/fluoroalkoxy phosphorus ligands in the L2Fe(CO)3 system. Inorganica Chim Acta 1999. [DOI: 10.1016/s0020-1693(99)00020-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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46
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Creve S, Oevering H, Coussens BB. Substituent and Solvent Effects in the Insertion and Isomerization of Olefins by Platinum(bis-phosphine) Complexes: An ab Initio Study of the Pt(PR3)2H(propene)+ Model Systems. Organometallics 1999. [DOI: 10.1021/om9806895] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Steven Creve
- Department of Chemistry, University of Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium, and DSM Research, P.O. Box 18, 6160 MD Geleen, The Netherlands
| | - Henk Oevering
- Department of Chemistry, University of Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium, and DSM Research, P.O. Box 18, 6160 MD Geleen, The Netherlands
| | - Betty B. Coussens
- Department of Chemistry, University of Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium, and DSM Research, P.O. Box 18, 6160 MD Geleen, The Netherlands
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Fernandez AL, Lee TY, Reyes C, Prock A, Giering WP. A Thermodynamically Based and Definitive Demonstration of the Inadequacy of the ECW Model for Phosphorus(III) Ligands. Organometallics 1998. [DOI: 10.1021/om980262y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anthony L. Fernandez
- Department of Chemistry, Metcalf Science and Engineering Center, Boston University, Boston, Massachusetts 02215
| | - Tsung Ying Lee
- Department of Chemistry, Metcalf Science and Engineering Center, Boston University, Boston, Massachusetts 02215
| | - Clementina Reyes
- Department of Chemistry, Metcalf Science and Engineering Center, Boston University, Boston, Massachusetts 02215
| | - Alfred Prock
- Department of Chemistry, Metcalf Science and Engineering Center, Boston University, Boston, Massachusetts 02215
| | - Warren P. Giering
- Department of Chemistry, Metcalf Science and Engineering Center, Boston University, Boston, Massachusetts 02215
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48
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Fernandez A, Reyes C, Prock A, Giering WP. Exploring Ligand Effects through Isoequilibrium Phenomena: The Quantitative Analysis of Ligand Effects. Organometallics 1998. [DOI: 10.1021/om971041f] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anthony Fernandez
- Department of Chemistry, Metcalf Science and Engineering Center, Boston University, Boston, Massachusetts 02215
| | - Clementina Reyes
- Department of Chemistry, Metcalf Science and Engineering Center, Boston University, Boston, Massachusetts 02215
| | - Alfred Prock
- Department of Chemistry, Metcalf Science and Engineering Center, Boston University, Boston, Massachusetts 02215
| | - Warren P. Giering
- Department of Chemistry, Metcalf Science and Engineering Center, Boston University, Boston, Massachusetts 02215
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