Computational Insight into <sup>103</sup>Rh Chemical Shift–Structure Correlations in Rhodium Bis(phosphine) Complexes

Ortuño, Manuel Á.; Castro, Ludovic; Bühl, Michæl

doi:10.1021/om400774y

Cited by 8 publications

(6 citation statements)

References 62 publications

(80 reference statements)

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“…Thus, a DFT study of the RuCl 2 (P A -N)(PR 3 )L complexes seemed highly appropriate to help quantify details of the observed, inverse NMR/structural plot of Figure , and this led to the collaborative research described in this current paper. A theoretical study by Bühl’s group that derived a correlation between experimental or computed Rh–P bond lengths and computed 103 Rh chemical shifts for a series of Rh phosphine-containing complexes also encouraged us to venture into this area; of note, an increasing Rh–P bond length corresponded to an increase in the 103 Rh chemical shift, which is opposite to the correlation between the 31 P chemical shift and the Ru–P distance seen in Figure .…”

Section: Introductionmentioning

confidence: 99%

³¹P Chemical Shifts in Ru(II) Phosphine Complexes. A Computational Study of the Influence of the Coordination Sphere

et al. 2020

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NMR chemical shift has been the most versatile marker of chemical structures, by reflecting global and local electronic structures, and is very sensitive to any change within the chemical species. In this work, a set of Ru(II) complexes with the same five ligands and a variable 6 th ligand L (none, H2O, H2S, CH3SH, H2, N2, N2O, NO + , C=CHPh, and CO) is studied, using as the NMR reporter, the phosphorus PA of a coordinated bidentate PAN ligand (PAN = o-diphenylphosphino-N,N'dimethylaniline). The chemical shift of PA in RuCl2(PAN)(PR3)(L) (R = phenyl, p-tolyl or p-FC6H4) was shown to increase as the RuPA bond distance decreases, an observation that was not rationalized. This work, using density functional theory (DFT) calculations, reproduces reasonably well the observed 31 P chemical shifts for these complexes, and the correlation between the shifts and the RuPA bond distance as L varies. An interpretation of this correlation is proposed using a Natural Chemical Shift (NCS) analysis based on the Natural Bonding Orbital (NBO) method. This analysis of the principal components of the chemical shift tensors shows how the s-donating properties of L have a particularly high influence on the phosphine chemical shifts.

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Section: Introductionmentioning

confidence: 99%

³¹P Chemical Shifts in Ru(II) Phosphine Complexes. A Computational Study of the Influence of the Coordination Sphere

et al. 2020

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“…Here, the challenge of separating and quantifying the electronic and steric properties of a particular complex to rationalise the adopted exo/endo isomeric preference. Similarly, isolating the contributions to the paramagnetic term (Equation 1) is difficult; although, several computational studies have been used to distinguish the contributions, [52][53][54] However, the aforementioned correspondence observed between the exo/endo ratios and chemical shifts highlights the utility of NMR in establishing empirical correlations between chemical shifts of NMR-active transition metal nuclei, and the dynamic behaviour, chemical reactivity and even catalytic activity of their organometallic complexes. As a particularly interesting example, catalytic efficacy of complexes [(η 5 -R-Cp)Co(COD)] (COD = 1,6-cyclooctadiene, R-Cp = monosubstituted cyclopentadienyl) with regards to the cyclotrimerisation of acetylenes and nitriles has been shown to correlate with their respective 59 Co chemical shifts.…”

Section: 3mentioning

confidence: 99%

“…Whereas 95 Mo NMR spectroscopy is potentially useful here, the literature on 53 Cr NMR is very scarce, since the relatively large quadrupolar moment of 53 Cr and its low receptivity make it a particularly challenging nucleus to probe. [45,56,57,65] However, the differences between the Cr and corresponding Mo and W complexes make 53 Cr NMR experiments potentially interesting. 183 W is an I = ½ nucleus that exhibits a number of measurement difficulties, on account of its low receptivity and long relaxation times.…”

Section: 3mentioning

confidence: 99%

η3-Allyl carbonyl complexes of group 6 metals: Structural aspects, isomerism, dynamic behaviour and reactivity

Ryan

Cardin

Hartl

2017

Coordination Chemistry Reviews

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Contents 1. Introduction 2. Complexes [CpM(CO)2(η 3 -allyl)] and related compounds 2.1. Synthetic strategies 2.2. Exo ⇌ endo isomerism 2.3. 95 Mo and 183 W NMR spectroscopy 2.4. Oxidized cationic complexes -reactivity, fluxionality, structural features 2.5. Mixed nitrosyl carbonyl complexes [CpM(CO)(NO)(η 3 -allyl)] + (M = Mo, W) 3. Complexes [M(CO)2(η 3 -allyl)(α-diimine)X] (X = anionic monodentate ligand) and related compounds 3.1. Synthetic strategies 3.2. Mechanistic features, structural aspects, and dynamic behaviour 3.3. Monodentate ligands bound to M(CO)2(η 3 -allyl)(L⏜L): reactivity and intermediacy in allylic alkylations 3.4. Redox Properties and Electrocatalysis 4. Amidinato and pyrazolato complexes related to [M(CO)2(η 3 -allyl)(α-diimine)X] 4.1. Synthesis and dynamic behaviour 4.2. Coordinatively unsaturated species and their reactivity 5. Summary and outlook Acknowledgement References 2 ABSTRACTTransition metal complexes with π-allylic ligands remain an attractive topic in organometallic chemistry, given the numerous reports of a wide variety of synthetic routes, dynamic behaviour and reactivity, structural (including isomerism), spectroscopic and redox properties, and applications in organic synthesis and catalysis. Surprisingly, despite the considerable interest in the rich and varied chemistry of this family of organometallic compounds, there is no recent review. This review is focused on π-allylic representatives of low-cost Group-6 metals bearing one or more carbonyl ligand, the coordination sphere being complemented with η 5cyclopentadienyl (Section 2), chelating ligands, including redox active α-diimines and various complementary diphosphine (Section 3) and novel anionic amidinate or pyrazolate (Section 4) ligands. In Section 1 particular attention is paid to rearrangements of the π-allylic ligand, namely exo and endo isomerism, interconversion mechanisms, fluxionality, and agostic interactions. In addition, the application of multinuclear NMR spectroscopy to the elucidation of such isomerism, and the effect of the metal centre oxidation state on the bonding, dynamic behaviour and reactivity of the π-allylic ligand are described. The detailed mechanistic description of the synthetic routes and dynamic behaviour of selected representatives of αdiimine complexes in Section 2 is followed by a description of the [M(CO)2(η 3 -allyl-H,R)(αdiimine)] 0/+ fragment as a convenient scaffold for diverse monodentate ligands participating in a range of substitution, insertion, intramolecular migration and C-C coupling reactionsfrequently involving also the π-allylic ligand, such as allylic alkylation. Special attention is devoted to selected examples of redox and acid-base reactivity of the α-diimine complexes with emphasis on prospects in electrocatalysis. The amidinate (and related pyrazolate) ligands treated in Section 4 may directly replace the π-allylic ligand in some cyclopentadienyl complexes (Section 2) or the α-diimine ligand in some dicarbonyl π-allylic complexes (Section 3). The brief description...

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“…Note that computations of 103 Rh NMR chemical shifts have been presented in previous studies; [67][68][69][70][71][72][73][74][75][76] however, as previously elusive experimental data are now accessible via techniques like the triple resonance experiments, there is a need for a robust and widely applicable computational protocol, especially for the dirhodium complexes that play a crucial role in asymmetric catalysis. In general, the combination of measured and computed NMR isotropic chemical shifts as well as shielding tensors has proven to be a powerful tool in rationalizing how subtle structural changes affect the electronic structure of a broad variety of nuclei.…”

Section: Introductionmentioning

confidence: 99%

Elucidating the Electronic Nature of Rh‐based Paddlewheel Catalysts from ¹⁰³Rh NMR Chemical Shifts: Insights from Quantum Mechanical Calculations

Gui,

Sorbelli,

Caló

et al. 2023

Chemistry A European J

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The tremendous importance of dirhodium paddlewheel com‐plexes for asymmetric catalysis is largely the result of anempirical optimization of the chiral ligand sphere aboutthe bimetallic core. Only recently, a H(C)Rhtriple resonance 103Rh NMR experiment provided the long‐awaited opportunity to examine – with previously incon‐ceivable accuracy – how variation of the ligands impacts onthe electronic structure of such catalysts. The recorded ef‐fects are dramatic: formal replacement of one out ofeight O‐atoms in a dirhodium tetracarboxylate by an N‐atom results in a shielding of thecorresponding Rh‐site of no less than 1000 ppm. The cur‐rent paper provides the framework that allowsthis and related experimental observations made with a setof 19 representative rhodium complexes to be interpreted.In line with symmetry considerations, it is shown that theshielding tensor responds only to the donor ability of theequatorial ligands along the perpendicular principal axis.Axial ligands, in contrast, have no direct effect on shield‐ing but exert an electronic cis‐effect that onto the neighboring equatorial sites. Furthermore, charge redistribution within the core as well as the electronic trans‐effect of ligands ofdifferent donor strengths is reflected in the 103 Rh NMR shifts.

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Computational Insight into ¹⁰³Rh Chemical Shift–Structure Correlations in Rhodium Bis(phosphine) Complexes

Cited by 8 publications

References 62 publications

³¹P Chemical Shifts in Ru(II) Phosphine Complexes. A Computational Study of the Influence of the Coordination Sphere

³¹P Chemical Shifts in Ru(II) Phosphine Complexes. A Computational Study of the Influence of the Coordination Sphere

η3-Allyl carbonyl complexes of group 6 metals: Structural aspects, isomerism, dynamic behaviour and reactivity

Elucidating the Electronic Nature of Rh‐based Paddlewheel Catalysts from ¹⁰³Rh NMR Chemical Shifts: Insights from Quantum Mechanical Calculations

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Computational Insight into 103Rh Chemical Shift–Structure Correlations in Rhodium Bis(phosphine) Complexes

Cited by 8 publications

References 62 publications

31P Chemical Shifts in Ru(II) Phosphine Complexes. A Computational Study of the Influence of the Coordination Sphere

31P Chemical Shifts in Ru(II) Phosphine Complexes. A Computational Study of the Influence of the Coordination Sphere

η3-Allyl carbonyl complexes of group 6 metals: Structural aspects, isomerism, dynamic behaviour and reactivity

Elucidating the Electronic Nature of Rh‐based Paddlewheel Catalysts from 103Rh NMR Chemical Shifts: Insights from Quantum Mechanical Calculations

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Computational Insight into ¹⁰³Rh Chemical Shift–Structure Correlations in Rhodium Bis(phosphine) Complexes

³¹P Chemical Shifts in Ru(II) Phosphine Complexes. A Computational Study of the Influence of the Coordination Sphere

³¹P Chemical Shifts in Ru(II) Phosphine Complexes. A Computational Study of the Influence of the Coordination Sphere

Elucidating the Electronic Nature of Rh‐based Paddlewheel Catalysts from ¹⁰³Rh NMR Chemical Shifts: Insights from Quantum Mechanical Calculations