Synthesis, Characterization and Reactivity of the First Osmium β-diketiminato Complexes. and Application in Catalysis. Supporting Information

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1 S1 of S37 Synthesis, Characterization and Reactivity of the First Osmium β-diketiminato Complexes and Application in Catalysis Dominique F. Schreiber, a Crystal O Connor, a,b Christian Grave, a Helge Müller-Bunz, a Rosario Scopelliti, c Paul J. Dyson, c and Andrew D. Phillips* a (a) School of Chemistry & Chemical Biology, University College Dublin (UCD), Belfield, Dublin 4, Ireland. (b) SFI Strategic Research Cluster in Solar Energy Conversion, University College Dublin (UCD), Belfield, Dublin 4, Ireland. (c) Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1014 Lausanne, Switzerland. Corresponding author's address: andrew.phillips@ucd.ie Table of Contents Selected crystallographic data for compounds 1-Os to 6-Os.... S2 Tables S1-S2: Selected crystallographic data for compounds 1-Os to 6-Os... S3 General Computational Details... S5 Tables S3-S9: Comparison between experimental crystallographic data (Xtal) and computationally optimized models (Model) of selected bond lengths and bond angles... S6 Comparison of Mayer Bond Indices... S11 Characterization of Transition States... S11 Results of the charge decomposition analysis (CDA) for complexes 2-Os/Ru... S12 Figures S1-S11: DFT Optimized gas phase structure of model complexes... S14-S34 Tables S11-S21: Selected structural parameters for the optimized gas phase geometry of model complexes... S15-S35 Additional references... S36

2 S2 of S37 Selected crystallographic data for compounds 1-Os to 6-Os General remarks: Suitable single crystals were removed from the sample vial under a flow of N 2 and manipulated in a perfluoropolyalkylether oil matrix (F06206K, ABCR company) using a specially constructed Dewar, partially filled with liquid N 2. The crystals were mounted to the end of a glass fiber (diameter at least 0.1 mm) or nylon loop attached to a copper pin fixed to a goniometer head which was placed in the Euler cradle, while maintaining a cold blanket of N 2 gas. Selected single crystals were kept under a 140 or 100 K gaseous flow of N 2 during the collection procedure.[1] For complexes 1-Os, 2-Os, 5-Os and 6-Os a Nonius Kappa-CCD diffractometer equipped with a Bruker-Apex II CCD area detector and an Enraf-Nonius FR590 X-ray generator was used. The unit cell and orientation matrices were determined by indexing reflections measured from phi- chi scans and analyzed with the program DIRAX.[2] The data sets collected using the Bruker instrument are based on collecting reflections using an optimized scanning strategy utilizing the programs CollectCCD.[3] After data integration with either EvalCCD,[4] a multi- scan absorption correction based on a semi- empirical method was applied using the SADABS.[5] The data for the rest of the complexes were collected using an Agilent-Oxford Diffraction Kuma diffractometer equipped with a Sapphire CCD area detector or a SuperNova type-a diffractometer fitted with an Atlas CCD detector. Unit cell determination, reflection collection and integration for Agilent-made instruments used the CrysAlias suite of programs and an analytical absorption correction based on the shape of the crystal were performed in all cases.[6] All instruments utilized graphite mono-chromated Mo-Kα radiation source with λ = Å. Doubly redundant datasets were collected in all cases, assuming that the Friedel pairs are not equivalent. Space group determination was performed with the XPREP program provided by Bruker.[7] All structures were solved by direct methods using SHELXS-97[8] and refined by full matrix least-squares on F 2 for all data using SHELXL-97.[8] Hydrogen atoms were added at calculated positions and refined using a riding model. The corresponding isotropic temperature factors were fixed to 1.2 times (1.5 times for methyl groups) the equivalent isotropic displacement parameters of the carbon atom to which the H-atom is attached. Anisotropic thermal displacement parameters were used for all non-hydrogen atoms. A small number of reflections in some cases were removed when Δ(F o 2- F c 2)/σ exceeded Figures in the main publication were produced with the program ORTEP-3 for windows,[9] and CIF data formatting was performed using programs PLATON,[10] WinGX,[11] and encifer.[12] Additional structural analysis was executed using Mercury 3.1.[13] Additional refinements procedures for specific molecules are detailed in the appropriate corresponding CIF. Important selected parameters for complexes 1-6-Os are shown in Table S1 and Table S2.

3 S3 of S37 Table S1: Selected crystallographic data for compounds 1-Os to 3-Os. Compound Parameter 1-Os a) 2-Os 3-Os Empirical formula C 111 H 127 Cl 13 N 8 Os 4 C 29 H 32 Cl 3 F 3 N 2 O 3 SOs C H N 2 O 3 F 3 SCl 2.23 Os Fwt. (g mol -1 ) Cryst syst. Triclinic Triclinic Monoclinic Space Group P-1 (no. 2) P-1 (no. 2) P2 1 /c (no. 14) a (Å) (11) (11) (2) b (Å) (8) (16) (2) c (Å) (14) (11) (3) α ( ) (5) (8) 90 β ( ) (8) (7) (1) γ ( ) (6) (9) 90 V (Å 3 ) (4) (3) (8) Z D calcd (g cm -3 ) Cryst dimens. (mm 3 ) T (K) 100(2) 103(2) 100(2) µ (mm -1 ) θ min./max. range ( ) 3.32 / / / Completeness θ (%) (99.0) (98.8) (99.6) F(000) No. of rflns collected No. of unique rflns No. of parameters No. of restraints R 1 /wr 2 (I>2σ(I)) b) / / / R 1 /wr 2 (all data) b) / / / GOF c) Min./Max. e - density (e Å -3 ) / / / Abs. Struct Notes: (a) Two crystallographic independent molecules present within the unit cell. (b) R 1 = Σ F o - F c /Σ F o, wr 2 = {Σ[w(F 2 o -F 2 c ) 2 ] / Σ[w(F 2 o ) 2 ]} ½. (c) GOF = {Σ[w(F 2 o -F 2 c ) 2 ] / (n-p)} ½ where n is the number of data and p is the number of parameters refined.

4 S4 of S37 Table S2: Selected crystallographic data for compounds 4-Os to 6-Os. Compound Parameter 4-Os 5-Os a) 6-Os Empirical formula C 32 H 41 N 2 O 4 F 3 SOs C 31 H 37 Cl 2 F 3 N 2 O 3 SOs C 37 H 40 F 3 N 3 O 3 SOs Fwt. (g mol -1 ) Cryst syst. Monoclinic Monoclinic Triclinic Space Group P2 1 /c (no. 14) P2 1 /c (no. 14) P-1 (no. 2) a (Å) (1) (3) (6) b (Å) (1) (2) (7) c (Å) (2) (4) (8) α ( ) (5) β ( ) (1) (2) (5) γ ( ) (5) V (Å 3 ) (5) (11) (16) Z D calcd (g cm -3 ) Cryst dimens. (mm 3 ) T (K) 100(2) 133(2) 140(2) µ (mm -1 ) θ min./max. range ( ) 3.29 / / / Completeness θ (%) (99.7) (99.9) (99.8) F(000) No. of rflns collected No. of unique rflns No. of parameters No. of restraints R 1 /wr 2 (I>2σ(I)) b) / / / R 1 /wr 2 (all data) b) / / / GOF c) Min./Max. e - density (e Å -3 ) / / / Abs. Struct Notes: (a) Some solvent molecules could not be located in the unit cell. Platon SQUEEZE was used to compensate for the spread electron density. (b) R 1 = Σ F o - F c /Σ F o, wr 2 = {Σ[w(F 2 o -F 2 c ) 2 ] / Σ[w(F 2 o ) 2 ]} ½. (c) GOF = {Σ[w(F 2 o -F 2 c ) 2 ] / (n-p)} ½ where n is the number of data and p is the number of parameters refined.

5 S5 of S37 General Computational Details All structures were optimized using density functional theory, specially employing the metageneralized gradient corrected approximation (GGA) M06L hybrid functional developed by Truhlar and co-workers.[14] This functional was used in combination with the mixed basis set using the Gen keyword implemented in Gaussian 09.[15] The heavy transition elements, Ru and Os were represented by the Stuttgart/Dresden effective core potential and associated basis set, SDDAll (both Ru and Os use the pseudo potential ECP28MWB),[16] while the remaining C, N, H atoms were modeled using the Pople-type basis sets, 6-31G(d,p).[17] The geometry optimization started from the available X-ray crystal structures of the synthesized complexes. To obtain energy minima, frequency calculations were also carried out on the optimized geometries at the same level of theory to assess the nature of stationary points, i.e., whether they correspond to transition states (TS) or higher-order saddle points. Zero-point energy corrections at 298 K have been obtained through frequency analyses obtained at the M06L level of theory with a mixed basis set, SDDAll and 6-31G(d,p), and are un-scaled. The main differences in computed geometrical parameters from the X-ray crystal structure geometries (given in bold) are reported in Table S3 to Table S9. Mayer bond indices (MBIs) and other types of population and charge analyses are based on single point calculations using the M06 level of theory and the basis sets used in the energy minimization procedure, visualization performed with the UCSF Chimera program.[18] The charge decomposition analyses utilizes the scheme developed by Frenking et al.[19,20] as implemented by the program AOMIX version 6.81 developed by S. I. Gorelsky of the University of Ottawa.[21] Images and parameter output data were compiled using the Gaussview program.[22]

6 S6 of S37 Table S3: Comparison between experimental crystallographic data (Xtal) and computationally optimized models (Model) of selected bond lengths (Å) and bond angles ( ) for complex 2-Ru. Parameter Model Xtal Difference Ru-N N-C aryl N-C α C α -C β C α -C Me Ru-Bz a N-Ru-N Ru-N-C aryl Ru-N-C α C aryl -N-C α N-C α -C β N-C α -C Me C α -C β -C α Bz a -Ru-C β Notes: (a) Bz refers to the centroid of the η 6 -C 6 H 6 ligand. Table S4: Comparison between experimental crystallographic data (Xtal) and computationally optimized models (Model) of selected bond lengths (Å) and bond angles ( ) for complex 2-Os. Parameter Model Xtal Difference Os-N N-C aryl N-C α Ca-C β C α -C Me Os-Bz a N-Os-N Os-N-C aryl Os-N-C α C aryl -N-C α N-C α -C β N-C α -C Me C α -C β -C α Bz a -Os-C β Notes: (a) Bz refers to the centroid of the η 6 -C 6 H 6 ligand.

7 S7 of S37 Table S5: Comparison between experimental crystallographic data (Xtal) and computationally optimized models (Model) of selected bond lengths (Å) and bond angles ( ) for complex 4-Ru. Parameter Model Xtal Difference Ru-N N-C aryl N-C α C α -C β C α -C Me Ru-Bz a N-Ru-N Ru-N-C aryl Ru-N-C α C aryl -N-C α N-C α -C β N-C α -C Με C α -C β -C α Bz a -Ru-C β Notes: (a) Bz refers to the centroid of the η 6 -C 6 H 6 ligand. Table S6: Comparison between experimental crystallographic data (Xtal) and computationally optimized models (Model) of selected bond lengths (Å) and bond angles ( ) for complex 4-Os. Parameter Model Xtal Difference Os-N N-C aryl N-C α C α -C β C α -C Me Os-Bz a N-Os-N Os-N-C aryl Os-N-C α C aryl -N-C α N-C α -C β N-C α -C Me C α -C β -C α Bz a -Os-C β Notes: (a) Bz refers to the centroid of the η 6 -C 6 H 6 ligand.

8 S8 of S37 Table S7: Comparison between experimental crystallographic data (Xtal) and computationally optimized models (Model) of selected bond lengths (Å) and bond angles ( ) for complex 5-Ru. Parameter Model Xtal Difference Ru-N N-C aryl N-C α C α -C β C α -C Me Ru-Bz Ru-C(H 2 ) C(H 2 )-C(H 2 ) C(H 2 )-C β N-Ru-N Ru-N-C aryl Ru-N-C α C aryl -N-C α N-C α -C β N-C α -C Me C α -C β -C α Bz-Ru-C β Ru-C(H 2 )-C(H 2 ) C(H 2 )-C(H 2 )-C β N-Ru-C(H 2 ) Notes: (a) Bz refers to the centroid of the η 6 -C 6 H 6 ligand.

9 S9 of S37 Table S8: Comparison between experimental crystallographic data (Xtal) and computationally optimized models (Model) of selected bond lengths (Å) and bond angles ( ) for complex 5-Os. Parameter Model Xtal Difference Os-N N-C aryl N-C α C α -C β C α -C Me Os-Bz a Os-C(H 2 ) C(H 2 )-C(H 2 ) C(H 2 )-C β N-Os-N Os-N-C aryl Os-N-C α C aryl -N-C α N-C α -C β N-C α -C Me C α -C β -C α Bz a -Os-C β Os-C(H 2 )- C(H 2 ) C(H 2 )-C(H 2 )- C β N-Os-C(H 2 ) Notes: (a) Bz refers to the centroid of the η 6 -C 6 H 6 ligand.

10 S10 of S37 Table S9: Comparison between experimental crystallographic data (Xtal) and computationally optimized models (Model) of selected bond lengths (Å) and bond angles ( ) for complex 6-Os. Parameter Model Xtal Difference Os-N N-C aryl N-C α C α -C β C α -C Me Os-Bz a Os-C(N) C(Os)-N(Xy) N-Os-N Os-N-C aryl Os-N-C α C aryl -N-C α N-C α -C β N-C α -C Me C α -C β -C α Bz a -Os-C β Bz a -Os- C(NXy) Os-C-N(Xy) C(Os)-N-C(Xy) Notes: (a) Bz refers to the centroid of the η 6 -C 6 H 6 ligand.

11 S11 of S37 Comparison of Mayer Bond Indices The Mayer bond index provides a normalized population analysis of bonds within a specific molecule.[23] It enables a direct comparison between different types of bonds. Generally, large values are associated with stronger bonds and higher electron density. Table S10 lists the Mayer bond indices for selected bonds in complexes. Table S10: Mayer bond index comparison for model Ru and Os complexes. Bond 2-Ru 2-Os 4-Ru 4-Os 5-Ru 5-Os 6-Os Ru-N Bz a -M N-C α N-Ar C α -C β C α -C (CH3) M-H M-C (CH2) C=C C (CH2) -C β C=N Notes: (a) Represents the average from the six connecting carbon atoms of the benzene ring. Characterization of Transition States For the heterolytic cleavage of H 2 by complexes 2-Os or 2-Ru, the corresponding transition state features an imagery frequency (4-Ru : cm -1 and 4-Os : cm -1 ) corresponding to the simultaneous protonation of the β-carbon site on the β-diketiminate ligand and formation of a metal hydride. The Mayer bond indices indicate a stronger metalhydride interaction in the case of 4-Os (0.400 versus for 4-Ru ), whereas the new C β - H bonds are essentially equal for both transition states, 4-Ru (0.304) compared with 4-Os (0.303). The bond strength of the activated H-H is less in 4-Os (0.546) than in 4-Ru (0.592), and H 2 can be considered significantly activated by the complexes considering the MBI for free H 2 is 1.00 (set by definition of MBI). In regards to [4+2] alkene cycloaddition involving 2-Os or 2-Ru, the corresponding transition state features an imagery frequency (5-Ru : cm -1 and 5-Os : cm -1 ) corresponding to the simultaneous C-C bond formation involving the β-carbon site on the β- diketiminate ligand and creation of a new metal-carbon bond. The Mayer bond indices

12 S12 of S37 indicate the extent of activation for ethylene is equal for both complexes, as the values are generally equivalent, except for a slightly stronger metal-carbon bond for Os. 5-Ru (Ru-C: 0.446, C(H 2 )-C(H 2 ): 1.510, C-C β : 0.273) 5-Os (Os-C: 0.454, C(H 2 )-C(H 2 ): 1.505, C-C β : 0.275). In the transition states 5-Ru and 5-Os, the C(H 2 )-C(H 2 ) π-bond is clearly activated (C-C bond order reduced by 37%) as compared the free ethylene, which has a MBI of Results of the charge decomposition analysis (CDA) for complexes 2-Os/Ru M 2 N M N N N Scheme S1 Since the symmetry of both complexes 2-Os and 2-Ru is restricted to C 2v, the relevant irreducible representations correspond to A 1, A 2, B 1 and B 2. Thus, it is possible to differentiate σ- and π-bonding contributions between the β-diketiminate and metal center.[24] Overall, the charge transfer from filled β-diketiminate fragment orbitals (FO) into vacant metal-η 6 -arene FOs was found to be electrons for 2-Os and electrons for 2-Ru. Interestingly, the charge transfer from π-interactions based on A 2 and B 1 type MOs are approximately equal, 2- Ru and 2-Os However, a more significant difference between the complexes originates from the in-plane σ-bonding, where the A 1 and B 2 type MOs in 2-Ru provide in terms of electron charge transfer, whereas the 2-Os complex features less at Upon closer inspection, for both complexes, the primary orbital overlap between the metal and β- diketiminate occurs predominantly between the B 1 -type HOFO(β-diketiminate) and LUFO+1(arene-M) and the B 2 -type HOFO-1(β-diketiminate) and the LUFO(arene-M) as indicated by the largest charge transfers within the individual FOs. Remarkably, back donation from the η 6 -arene-metal fragment into a vacant π -type β-diketiminate FO, would be possible based on the availability of correct symmetry adapted orbitals, but is found to be non-existent for both complexes due to energy level mismatches. N M N M N N Scheme S2

13 S13 of S37 It is well established in organometallic chemistry that η 6 -arene class of ligands are both strong π-donors and π-acceptors.[25] However, in light of the strong σ- and π-donor capabilities of the β-diketiminate ligand, it is interesting to quantify the extent of electronic changes within the η 6 -arene fragment for both 2-Ru and 2-Os. As established experimentally by X-ray crystallography, a distortion of the planar η 6 -arene ring is noted in both complexes. This observation suggests that considerable η 4 -C 6 R 6 diene-type bonding character is present within these systems, and is represented in the extreme when hexamethylbenzene is employed as a ligand.[26] In regards to the electron donation from the arene into mainly empty d-orbitals of the metal-β-diketiminate FOs, an overall donation of and electrons was calculated for Os and Ru, respectively. Here, the primary FOs involved are the B 1 -type HOFO(arene) and LUFO(M-β-diketiminate) and the B 2 -type HOFO-1(arene) and LUFO+1(β-diketiminate-M). As expected, a considerable amount of back bonding is observed, where charge transfer occurs from the occupied HOFO-6(β-diketiminato-Ru) into the vacant π* LUFO+1(arene) and from HOFO-3(β-diketiminato-Os) into the π* LUFO+1(arene), all of A 2 character. Overall, 2-Os shows increased back donation of electrons, compared to 2-Ru with electrons.

14 S14 of S37 Gaussian G09 optimized output parameters and structure of model complex 2-Ru Figure S1: DFT Optimized gas phase structure of 2-Ru, front (top) and top view (bottom).

15 S15 of S37 Table S11: Selected structural parameters for the optimized gas phase geometry of 2-Ru. Nr. Atom NA NB NC Bond Angle Dihedral X Y Z 1 C C C H C H C H C H H H Ru N N C C C C C C C C C C C H H H H C C C C H H H C C C C C H H H H H H H H C H H H H H H H H H H

16 S16 of S37 Gaussian G09 optimized output parameters and structure of model complex 2-Os Figure S2: DFT Optimized gas phase structure of 2-Os, front (top) and top view (bottom).

17 S17 of S37 Table S12: Selected structural parameters for the optimized gas phase geometry of 2-Os. Nr. Atom NA NB NC Bond Angle Dihedral X Y Z 1 C C C H C H C H C H H H Os N N C C C C C C C C C C C H H H H C C C C H H H C C C C C H H H H H H H H C H H H H H H H H H H

18 S18 of S37 Gaussian G09 optimized output parameters and structure of model complex 4-Ru Figure S3: DFT Optimized gas phase structure of 4-Ru, front (top) and top view (bottom).

19 S19 of S37 Table S13: Selected structural parameters for the optimized gas phase geometry of 4-Ru. Nr. Atom NA NB NC Bond Angle Dihedral X Y Z 1 C C C C C C H H H H H N N C C C C C H H H H H H H C C C C C C H H H C C C C C C H H H H C H H H C H H H C H H H C H H H Ru H H

20 S20 of S37 Gaussian G09 optimized output parameters and structure of model complex 4-Ru. Figure S4: DFT Optimized gas phase structure of 4-Ru, front (top) and top view (bottom).

21 S21 of S37 Table S14: Selected structural parameters for the optimized gas phase geometry of 4-Ru. Nr. Atom NA NB NC Bond Angle Dihedral X Y Z 1 C C C C C C H H H H H N N C C C C C H H H H H H H C C C C C C H H H C C C C C C H H H H C H H H C H H H C H H H C H H H H H Ru

22 S22 of S37 Gaussian G09 optimized output parameters and structure of model complex 4-Os Figure S5: DFT Optimized gas phase structure of 4-Os, front (top) and top view (bottom).

23 S23 of S37 Table S15: Selected structural parameters for the optimized gas phase geometry of 4-Os. Nr. Atom NA NB NC Bond Angle Dihedral X Y Z 1 C C C C C C H H H H H N N C C C C C H H H H H H H C C C C C C H H H C C C C C C H H H H C H H H C H H H C H H H C H H H Os H H

24 S24 of S37 Gaussian G09 optimized output parameters and structure of model complex 4-Os. Figure S6: DFT Optimized gas phase structure of 4-Os, front (top) and top view (bottom).

25 S25 of S37 Table S16: Selected structural parameters for the optimized gas phase geometry of 4-Os. Nr. Atom NA NB NC Bond Angle Dihedral X Y Z 1 C C C C C C H H H H H N N C C C C C H H H H H H H C C C C C C H H H C C C C C C H H H H C H H H C H H H C H H H C H H H Os H H

26 S26 of S37 Gaussian G09 optimized output parameters and structure of model complex 5-Ru Figure S7: DFT Optimized gas phase structure of 5-Ru, front (top) and top view (bottom).

27 S27 of S37 Table S17: Selected structural parameters for the optimized gas phase geometry of 5-Ru. Nr. Atom NA NB NC Bond Angle Dihedral X Y Z 1 C C C C C C H H H H H N N C C C C C H H H H H H H C C C C C C H H H C C C C C C H H H H C H H H C H H H C H H H C H H H C C H H H H Ru

28 S28 of S37 Gaussian G09 optimized output parameters and structure of model complex 5-Ru. Figure S8: DFT Optimized gas phase structure of 5-Ru, front (top) and top view (bottom).

29 S29 of S37 Table S18: Selected structural parameters for the optimized gas phase geometry of 5-Ru. Nr. Atom NA NB NC Bond Angle Dihedral X Y Z 1 C C C C C C H H H H H N N C C C C C H H H H H H H C C C C C C H H H C C C C C C H H H H C H H H C H H H C H H H C H H H C C H H H H Ru

30 S30 of S37 Gaussian G09 optimized output parameters and structure of model complex 5-Os Figure S9: DFT Optimized gas phase structure of 5-Os, front (top) and top view (bottom).

31 S31 of S37 Table S19: Selected structural parameters for the optimized gas phase geometry of 5-Os. Nr. Atom NA NB NC Bond Angle Dihedral X Y Z 1 C C C C C C H H H H H N N C C C C C H H H H H H H C C C C C C H H H C C C C C C H H H H C H H H C H H H C H H H C H H H Os C C H H H H

32 S32 of S37 Gaussian G09 optimized output parameters and structure of model complex 5-Os. Figure S10: DFT Optimized gas phase structure of 5-Os, front (top) and top view (bottom).