Probing the Donor Properties of Pincer Ligands Using Rhodium Carbonyl Fragments: An Experimental and Computational Case Study

Overview

Journal Eur J Inorg Chem

Date 2019 Oct 11

PMID 31598095

Citations 6

Authors

Gemma L Parker

Samantha Lau

Baptiste Leforestier

Adrian B Chaplin

Affiliations

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Abstract

Metal carbonyls are commonly employed probes for quantifying the donor properties of monodentate ligands. With a view to extending this methodology to -tridentate "pincer" ligands, the spectroscopic properties [ν(CO), , ] of rhodium(I) and rhodium(III) carbonyl complexes of the form [Rh(pincer)(CO)][BAr ] and [Rh(pincer)Cl(CO)][BAr ] have been critically analysed for four pyridyl-based pincer ligands, with two flanking oxazoline (NNN), phosphine (PNP), or N-heterocyclic carbene (CNC) donors. Our investigations indicate that the carbonyl bands of the rhodium(I) complexes are the most diagnostic, with frequencies discernibly decreasing in the order NNN > PNP > CNC. To gain deeper insight, a DFT-based energy decomposition analysis was performed and identified important bonding differences associated with the conformation of the pincer backbone, which clouds straightforward interpretation of the experimental IR data. A correlation between the difference in carbonyl stretching frequencies Δν(CO) and calculated thermodynamics of the Rh/Rh redox pairs was identified and could prove to be a useful mechanistic tool.

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References

Andrew R, Gonzalez-Sebastian L, Chaplin A . NHC-based pincer ligands: carbenes with a bite. Dalton Trans. 2015; 45(4):1299-305. DOI: 10.1039/c5dt04429d. View

Kumar A, Bhatti T, Goldman A . Dehydrogenation of Alkanes and Aliphatic Groups by Pincer-Ligated Metal Complexes. Chem Rev. 2017; 117(19):12357-12384. DOI: 10.1021/acs.chemrev.7b00247. View

Lin Y, Li G, Mao S, Chai J . Long-Range Corrected Hybrid Density Functionals with Improved Dispersion Corrections. J Chem Theory Comput. 2015; 9(1):263-72. DOI: 10.1021/ct300715s. View

Feller M, Diskin-Posner Y, Leitus G, Shimon L, Milstein D . Direct observation of reductive elimination of MeX (X = Cl, Br, I) from Rh(III) complexes: mechanistic insight and the importance of sterics. J Am Chem Soc. 2013; 135(30):11040-7. DOI: 10.1021/ja401852c. View

Peris E, Crabtree R . Key factors in pincer ligand design. Chem Soc Rev. 2018; 47(6):1959-1968. DOI: 10.1039/c7cs00693d. View

Grimme S, Antony J, Ehrlich S, Krieg H . A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu. J Chem Phys. 2010; 132(15):154104. DOI: 10.1063/1.3382344. View

Frenking G, Loschen C, Krapp A, Fau S, Strauss S . Electronic structure of CO--an exercise in modern chemical bonding theory. J Comput Chem. 2006; 28(1):117-26. DOI: 10.1002/jcc.20477. View

Leuthausser S, Schwarz D, Plenio H . Tuning the electronic properties of N-heterocyclic carbenes. Chemistry. 2007; 13(25):7195-203. DOI: 10.1002/chem.200700228. View

van der Boom M, Milstein D . Cyclometalated phosphine-based pincer complexes: mechanistic insight in catalysis, coordination, and bond activation. Chem Rev. 2003; 103(5):1759-92. DOI: 10.1021/cr960118r. View

10.

Mitoraj M, Michalak A, Ziegler T . A Combined Charge and Energy Decomposition Scheme for Bond Analysis. J Chem Theory Comput. 2015; 5(4):962-75. DOI: 10.1021/ct800503d. View

11.

Maser L, Schneider C, Vondung L, Alig L, Langer R . Quantifying the Donor Strength of Ligand-Stabilized Main Group Fragments. J Am Chem Soc. 2019; 141(18):7596-7604. DOI: 10.1021/jacs.9b02598. View

12.

Pike S, Crimmin M, Chaplin A . Organometallic chemistry using partially fluorinated benzenes. Chem Commun (Camb). 2017; 53(26):3615-3633. DOI: 10.1039/c6cc09575e. View

13.

Guzei I, Wendt M . An improved method for the computation of ligand steric effects based on solid angles. Dalton Trans. 2006; (33):3991-9. DOI: 10.1039/b605102b. View

14.

Reinholdt A, Bendix J . Weakening of Carbide-Platinum Bonds as a Probe for Ligand Donor Strengths. Inorg Chem. 2017; 56(20):12492-12497. DOI: 10.1021/acs.inorgchem.7b01956. View

15.

Benito-Garagorri D, Kirchner K . Modularly designed transition metal PNP and PCP pincer complexes based on aminophosphines: synthesis and catalytic applications. Acc Chem Res. 2008; 41(2):201-13. DOI: 10.1021/ar700129q. View

16.

Droge T, Glorius F . The measure of all rings--N-heterocyclic carbenes. Angew Chem Int Ed Engl. 2010; 49(39):6940-52. DOI: 10.1002/anie.201001865. View

17.

Altun A, Neese F, Bistoni G . Effect of Electron Correlation on Intermolecular Interactions: A Pair Natural Orbitals Coupled Cluster Based Local Energy Decomposition Study. J Chem Theory Comput. 2018; 15(1):215-228. DOI: 10.1021/acs.jctc.8b00915. View

18.

Bistoni G, Rampino S, Scafuri N, Ciancaleoni G, Zuccaccia D, Belpassi L . How π back-donation quantitatively controls the CO stretching response in classical and non-classical metal carbonyl complexes. Chem Sci. 2018; 7(2):1174-1184. PMC: 5975789. DOI: 10.1039/c5sc02971f. View

19.

Andrew R, Chaplin A . Synthesis and reactivity of NHC-based rhodium macrocycles. Inorg Chem. 2014; 54(1):312-22. DOI: 10.1021/ic5024828. View

20.

Weigend F, Ahlrichs R . Balanced basis sets of split valence, triple zeta valence and quadruple zeta valence quality for H to Rn: Design and assessment of accuracy. Phys Chem Chem Phys. 2005; 7(18):3297-305. DOI: 10.1039/b508541a. View