Further, we investigated the reaction of imino-iodane 4Ns with 1. P1 by means of high-resolution. ESI-MS (Figure S4-12). Remarkably, in contrast to the reaction ...
Supporting information
Monalisa Goswami,†,^ Volodymyr Lyaskovskyy,†,^ Sérgio R. Domingos,‡ Wybren Jan Buma,‡ Sander Woutersen,‡ Oliver Troeppner,§ Ivana Ivanović-Burmazović,§ Hongjian Lu,┴ Xin Cui,┴ X. Peter Zhang,┴,* Edward J. Reijerse,║ Serena DeBeer,║ Matti M. van Schooneveld,║ Florian Pfaff,# Kallol Ray,# and Bas de Bruin†,*
†
Van ’t Hoff Institute for Molecular Sciences (HIMS), Homogeneous and Supramolecular Catalysis, University of Amsterdam, Science Park 904, 1098 XH Amsterdam (The Netherlands). ‡
Van ’t Hoff Institute for Molecular Sciences (HIMS), Photonics group, University of Amsterdam, Science Park 904, 1098 XH Amsterdam (The Netherlands). §
Lehrstuhl für Bioanorganische Chemie, Department Chemie und Pharmazie, Universität Erlangen-Nürnberg. Egerlandstraße 1, D-91058 Erlangen (Germany). ┴
Department of Chemistry, University of South Florida, Tampa, FL 33620-5250 (USA).
║
Max Planck Institut für Chemische Energiekonversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr (Germany).
# Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin (Germany).
Contents 1.
Experimental details .......................................................................................................................................S2
2.
Synthetic Procedures ......................................................................................................................................S3
3.
Preparation of EPR and XAS samples ...........................................................................................................S8
4.
Mass spectrometric study .............................................................................................................................S12
5.
Copies of the EPR spectra ............................................................................................................................S29
6.
UV-Vis spectra ............................................................................................................................................S33
7.
IR and VCD data ..........................................................................................................................................S33
8.
Comparison of experimental and computed XANES data ...........................................................................S34
9.
Computational methods ................................................................................................................................S38
10.
Energies and optimized geometries (in .pdb format) ....................................................................................S40
S1
1. Experimental details NMR spectra were recorded at 293 K. 1H NMR: Bruker Avance 400 (400 MHz) or Bruker Avance 500 (500 MHz), referenced internally to residual solvent resonance of CHCl3 (δ = 7.26 ppm) or DMSO (2.50). 13C{1H} NMR: Bruker Avance 400 (101 MHz) or Bruker Avance 500 (126 MHz), referenced internally to residual solvent resonance of CDCl3 (δ = 77.2 ppm) or DMSO-d6 (39.5). HSQC(1H/15N) NMR: Bruker Avance 500 (50.7 MHz). X-band EPR spectra were recorded on a Bruker EMX spectrometer (Bruker BioSpin) equipped with a He temperature control cryostat system (Oxford Instruments). Simulations of the EPR spectra were performed by iteration of the anisotropic g-values and line widths using the EPR simulation program W95EPR developed by Prof. Dr. Frank Neese. High field EPR spectra were recorded on a home built instrument based on a quasi-optical mmwave bridge (244 GHz) and a 12T cryogenic magnet (Cryogenic Ltd) connected to a Sumitomo cryocooler. The sample was held in a Teflon cup and was accommodated in a non-resonant probehead based on a corrugated guide and taper (Reijerse, E.; Schmidt, P. P.; Klihm, G.; Lubitz, W. Appl. Magn. Reson. 2007, 31, 611626). Q-band Davies ENDOR experiments were performed on a Bruker Elexsys E580 spectrometer equipped with a Super Q-FT microwave bridge (34 GHz). The sample (2.8 mm diameter) was accommodated in a home-built TE011 CW/pulse ENDOR resonator (Reijerse, E.; Lendzian, F.; Isaacson, R.; Lubitz, W. J. Magn. Reson. 2012, 214, 237–243). The EPR resonator was cooled using an Oxford instruments CF935 Helium flow cryostat. X-band HYSCORE experiments were performed on a Bruker Elexsys E580 spectrometer equipped with a Super X-FT microwave bridge (9.5 GHz). The sample (3.8 mm diameter) was accommodated in the Bruker dielectric Resonator which was cooled using an Oxford instruments CF935 Helium flow cryostat.
UHR-ESI-MS spectra Description of the instrument: ESI-MS measurements were performed on a UHR-ToF Bruker Daltonik (Bremen, Germany) maXis, an ESI-ToF MS capable of resolution of at least 40,000 FWHM. Detection was in positive-ion mode with source voltage 4.5 kV and flow rates 250 µL/hour. The drying gas (N2) applied in the Cryo-MS measurements, which is used to aid solvent removal, was held at 35 °C. The applied spray gas temperature was 40 °C. The machine was calibrated prior to every measurement via direct infusion of the Agilent ESI-TOF low concentration tuning mixture, which provided an m/z range of singly charged peaks up to 2700 Da. Samples containing 5P1Ns (generated from 1P1 and 4Ns), 5P2Ns (generated from 1P2 and 4Ns), 3P1Ns (generated from 1P1 and 2Ns), 3P2Ts (generated from 1P2 and 2Ts), and 3P2troc (generated from 1P2 and 2troc) were measured on an AccuTOF LC, JMS-T100LP Mass spectrometer (JEOL, Japan) by replacing the ESI source with a CSI source (JEOL). CSI apparatus features a liquid nitrogen cooling device to maintain the temperature of the capillary and spray itself between 00C and 500C Typical measurement conditions are as follows: Positive-ion mode; Needle voltage 2000V, Orifice 1 voltage 90V, Orifice 2 voltage 9V, Ring Lens voltage 22V. Ion source temperature 30 0C, spray temperature -20 0C, solution flow rate 0.01 ml/min. All mass spectra were recorded with an average duration of 1 min. Preparation of the samples: 0.5 mg of the cobalt porphyrin was dissolved in 2 mL of benzene-d6 and an 100-fold excess of the respective azide-compound was added and allowed to stir for 30 S2
minutes. Prior to the measurement, the reaction mixture was diluted with acetonitrile. This is a requirement for proper ionization into the gas phase in ESI-MS studies.
2. Synthetic Procedures 1P2,1 nosyl azide 2Ns,2 tosyl azide 2Ts,3 troc azide 2troc,2 and N-nosyl iminoiodane (PhI=NNs) 4Ns,4 have been prepared according to literature procedures. 1P1 was bought from STREM chemicals and used without further purification. Synthesis of [15N-(p-nitrophyenylsulfonyl)imino]phenyliodinane] 15N-4Ns This compound was synthesized in two steps as described below.
Synthesis of p-nitrophenylsulfonyl amide Ns15NH2
p-Nitrophenylsulfonyl chloride NsCl (400 mg, 2.11 mmol) was dissolved in 20 mL of THF and 15 N-labled ammonia (gas) was added in small portions by bubbling it through the needle. After each addition of ammonia the reaction mixture was stirred for about 1 hour. The reaction was monitored with TLC, and when the peak of starting chloride disappeared, water (30 mL) and DCM (40 mL) were added. Organic phase was separated, and the water layer was washed with DCM (3×30 mL). Combined organic layers were washed with saturated sodium bicarbonate solution and dried over sodium sulfate. Evaporation of all volatiles gave target sulfamide Ns15NH2 in 63% yield (1.33 mmol, 270 mg). Compound was used without any further purification.
1
H NMR (500 MHz, DMSO-d6): 7.75 (d, 2H, 1JH15N = 82.0 Hz, NH2), 8.08 (d, 3JHH = 8.3 Hz, HAr), 8.43 (d, 3JHH = 8.3 Hz, HAr). 13
C{1H} NMR (APT) (126 MHz, DMSO-d6): 124.9 (CH), 127.7 (CH), 149.6 (CNO2), 149.8 (d, 2JCN = 3.0 Hz, CNH2). HSQC(1H/15N): 283.4.
1
Chen, Y.; Fields, K.B.; Zhang, X. P. J. Am. Chem. Soc. 2004, 126, 14718–14719. Lu, H.; Subbarayan, V.; Tao, J.; Zhang, X. P. Organometallics 2010, 29, 389–393. 3 Westheimer, H.; Closson, W. D.; Schulenberg, S. J. Am. Chem. Soc. 1970, 92:3, 650–657. 4 Wu, Q.; Hu, J.; Ren, X.; Zhou, J. Chemistry-a European Journal 2011, 17, 11553–11558. 2
S3
Synthesis of [15N-(p-nitrophyenylsulfonyl)imino nitrophenylsulfonyl amide Ns15NH2
phenyliodinane]
15
N-4Ns
from
p-
N15-nosyl iminoiodane 15N-4Ns was prepared according to the earlier reported synthesis of the non-labeled analogue 4Ns. Solid iodozobenzene diacetate (574 mg, 1.78 mmol) was added under nitrogen in small portion to a cooled to 0 ºC suspension of labeled nosyl amide Ns15NH2 (300 mg, 1.49 mmol) and (powdered) KOH (212 mg, 3.78 mmol) in 7 mL of dry MeOH over a period of 10 minutes. The resulting yellow suspension was stirred at 0 ºC for 30 min and then at room temperature for additional 3 h. The flask was wrapped with aluminum foil and left at room temperature over-night. Yellow precipitate was collected by filtration, washed with cold dry MeOH and diethyl ether and dried in vacuum. This gave N15-nosyl iminoiodane 15N-4Ns in 80% yield (482 mg, 1.19 mmol), which was used without further purification. 1
H NMR (500 MHz, DMSO-d6): 7.25 (t, 2H, 3JHH = 7.8 Hz, HPh-meta), 7.41(t, 1H, 3JHH = 6.5 Hz, HPh-para), 7.707.74 (m, 4H, HPh-ortho + HNs), 8.04 (d, 2H 3JHH = 9.4 Hz, HNs). Note: compound is not very stable in DMSO over long time. The NMR should be measured without delays. 13
C{1H} NMR (APT) (126 MHz, DMSO-d6): 117.6 (Cq), 124.0 (CH), 127.9 (CH), 130.6 (CH), 131.1 (CH), 134.1 (CH), 148.4 (Cq), 151.5 (Cq).
S4
Copies of the NMR spectra of all new compounds A.
1
H nmr spectra of p-nitrophenylsulfonyl amide Ns15NH2
1
H NMR spectrum
B. 13C { 1H }spectra APT of p-nitrophenylsulfonyl amide Ns15NH2
13
C { 1H } spectrum APT
S5
HSQC(1H/15N)
C. HSQC(1H/15N) of p-nitrophenylsulfonyl amide Ns15NH2 (TOP) D. 1H NMR spectra of [15N-(p-nitrophyenylsulfonyl)imino phenyliodinane] 15N-4Ns (BOTTOM)
1
H NMR spectrum
S6
13
C{1H} NMR (APT)
E. 13C{1H} NMR (APT) of [15N-(p-nitrophyenylsulfonyl)imino phenyliodinane] 15N-4Ns
S7
3. Preparation of EPR and XAS samples For EPR studies, dry degassed benzene-d6 was used as the solvent. Samples were prepared by dissolving 0.005 mmol of the catalyst (1P1 or 1P2) in 2 mL of benzene-d6 to which 0.5 mmol of the azide 2 (2Ns, 2Ts or 2troc) or iminoiodane 4Ns was added. All manipulations were carried out inside a glove box. Room temperature EPR spectra were recorded within 15 minutes of mixing and then the samples were thermostated at 45 oC and left overnight. EPR spectra were recorded again the next day. XAS measurements were performed on NSLS X3B, which is equipped with a sagitally focusing Si(111) double-crystal monochromator and a post-monochromator Ni-coated harmonic rejection mirror. Note that while the Ni mirror was in the beampath during data collection, metallic Ni contamination is not significant based on measurement of an experimental blank spectrum. Hence Cobalt EXAFS could only be collected up to the Nickel K-edge energy. The samples were prepared in Mössbauer/XAS cups made from Delrin® and the window side was sealed with Kapton® tape. All probes were made in benzene solution with a concentration of 10 mM and immediately frozen and stored at 77 K when the desired intermediate was formed in maximum yield, following reaction kinetics previously investigated by UV/vis and EPR spectroscopy. The temperature was kept below the melting point for storage period and transfer. A He Displex cryostat was used for temperature control during the measurement, with typical sample temperatures of ~20K. Data were collected as fluorescence spectra using a 31 element solid-state Ge detector (Canberra), over an energy range of 7508 – 8328 eV (k ~ 12 Å-1). Each scan required approximately 40 minutes. A Co foil spectrum was collected simultaneously using a PMT for energy calibration; the first inflection point of the metal foil reference was set to 7709 eV. Data averaging was carried out using Athena5 from the ifeffit package. Reference spectra for individual scans were carefully aligned to ensure that the energy scale was identical for all spectra. Sets of scans at each spot were examined for photoreduction effects. No evidence for photo reduction was observed based upon edge energies or spectral changes although slight burn marks were visible after the measurement. EXAFS analysis and fitting was performed with ArtemisFout! Verwijzingsbron niet gevonden.Fout! Verwijzingsbron niet gevonden.Fout! Verwijzingsbron niet gevonden. from the ifeffit package and FEFF 6. The fitting process is summarized in tables for each sample showing the major fitting parameters. The goodness of the fit (GOF) is represented by the R-factor (value from ifeffit 2
2
package) which is defined by 𝑅 = ∑[(𝜒𝑑𝑎𝑡 (𝑅𝑖 ) − 𝜒𝑡ℎ (𝑅𝑖 ) )/(𝜒𝑑𝑎𝑡 (𝑅𝑖 )) ].
S8
5
Demeter, Version 0.9.17, http://bruceravel.github.io/demeter/.
Figure S3-1: Normalized XANES spectra of 1P1 and 1P4 with 2Ns, 2troc or 4Ns. The spectra are energy corrected to a simultaneously measured reference Co-foil.
Figure S3-2: Overlaid Fourier transform EXAFS spectra for 1P1, 3P1Ns and 5P1Ns. All spectra are weighted by k3. S9
Figure S3-3: Fourier transform EXAFS spectra of 1P1 (dotted line) and the best fit (red line); the inset shows the EXAFS data on a wave vector scale weighted by k3 with respective representation.
S10
Table S3-1: Summary of EXAFS fitting for 5P1Ns. Bold line represents the best fit for the system (fit 12). r is in units of Å; σ² is in units of 10-3 Å; ΔE0 is in units of eV; R-factor represents the GOF. Fourier transform range: k 1.5-5.0 Å-1 . The fit was optimized in R space with a k-weight of 3. The fitting range is 0.8-2.1 Å for fits 1-2 and 0.8-4.8 for fits 3-11. Co-N/C Co···C/N Co···C/N Co···O/N fit R-factor ΔE0 n r σ² n r σ² n r σ² n r σ² 1' 0.070 -1.26 5 1.92 2.0 2' 0.062 -1.68 6 1.92 3.0 3 0.198 -1.80 6 1.92 3.1 4 0.109 0.36 6 1.93 3.1 8 2.94 4.2 5 0.087 -1.63 6 1.92 3.1 8 2.94 4.9 12 3.32 8.3 6 0.079 -0.94 6 1.93 3.1 8 2.95 5.0 12 3.32 7.9 7 0.077 -1.05 6 1.93 3.1 8 2.95 5.0 12 3.32 7.9 8 0.065 -1.61 6 1.92 3.1 8 2.95 5.1 12 3.31 7.7 4 4.79 0.7 9 0.051 -1.07 6 1.92 2.8 8 2.93 0.3 12 3.25 -0.8 4 3.79 2.9 10 0.042 -0.62 6 1.93 2.9 8 2.93 0.8 12 3.25 0.4 4 4.03 2.6 11 0.052 -1.53 6 1.92 3.0 8 2.94 4.3 12 3.32 9.6 2 5.30 -3.8 12 0.048 -1.21 6 1.92 3.0 8 2.94 4.5 12 3.35 8.7 4 3.57 2.2
n
Co···S r σ²
Co···N···C * n r σ²
16 16 16 2 3.19 -4.0 16 2 3.19 -2.9 16 1 3.73 -0.1 16 16
4.17 4.17 4.20 4.19 4.19 4.19 4.23
11.5 10.6 7.3 2.2 2.7 11.2 9.4
Co···C···C * n r σ²
32 32 32 32 32 32
5.39 4.00 3.98 4.52 4.57 4.55
Co···C···C * n r σ²
26.0 19.3 4.5 23.3 24 4.77 8.8 7.7 24 4.78 6.4 6.1 24 4.76 6.4
* multiscattering (2 legs) with a degeneracy of 2 for the shown paths and untreated σ² values.
Table S3-2: Summary of EXAFS fitting for 3P1Ns. Bold line represents the best fit for the system (fit 10). r is in units of Å; σ² is in units of 10-3 Å; ΔE0 is in units of eV; R-factor represents the GOF. Fourier transform range: k 1.5-5.0 Å-1 . The fit was optimzied in R space with a k-weight of 3. The fitting range is 0.8-2.1 for fits 1-3 and 1.2-5.0 for fits 4-11.
fit R-factor 1' 0.061 2' 0.035 3' 0.029 4' 0.038
ΔE0 3.40 2.86 2.30 1.70
n 4 5 6 7
Co-N/C Co···C/N Co···C/N Co···O/N Co···C/N * Co···N···C * r σ² n r σ² n r σ² n r σ² n r σ² n r σ² 1.95 1.5 1.95 2.7 1.95 3.8 1.95 4.8
5 6 7 8 9 10 11
3.45 3.30 2.55 1.96 2.05 2.33 2.35
6 6 6 6 6 6 6
1.96 1.96 1.95 1.95 1.95 1.95 1.95
0.085 0.065 0.045 0.037 0.032 0.023 0.025
3.8 3.8 3.7 3.7 3.7 3.6 3.7
8 8 8 8 8 8 8
3.00 3.01 3.00 3.00 3.00 2.99 3.00
7.0 6.2 6.5 6.5 6.3 6.2 6.6
12 12 12 12 12 12
3.35 3.37 3.37 3.38 3.39 3.39
15.1 13.6 14.1 16.3 18.5 14.5
2 2 2 2 4
3.60 3.60 3.61 3.62 3.63
0.7 0.8 1.0 2.1 2.4
12 12 12 12
4.93 4.93 4.93 4.93
Co···C···C * n r σ²
7.9 6.4 32 4.11 8.3 9.0 32 4.08 1.0 16 4.30 15.6 9.0 32 4.31 -0.1 16 4.31 -15.4
* multiscattering (2 legs) with a degeneracy of 2 for the shown paths and untreated σ² values. ' smaller fitting range
S11
Table S3-3: Summary of the EXAFS fitting for 1P1. The best fit for the date (fit 9) is represented in bold. r is in units of Å; σ² is in units of 10-3 Å; ΔE0 is in units of eV; R-factor represents the GOF. Fourier transform range: k 1.5-5.0 Å-1 . The fit was optimzied in R space with a k-weight of 3. The fitting range is 0.8-4.0 Å for fits 1-4 and 0.8-5.0 for fits 5-11. Co-N/C Co···C/N Co···C/N fit R-factor ΔE0 n r σ² n r σ² n r σ² 1' 0.311 -3.09 4 1.93 1.6 2' 0.136 0.20 4 1.94 1.8 8 2.98 2.1 3' 0.105 -1.01 4 1.94 1.7 8 2.97 2.7 4 3.32 2.5 4' 0.062 -0.75 4 1.94 1.8 8 2.97 2.9 4 3.33 1.8 5 0.832 -0.78 4 1.94 1.8 8 2.97 2.9 4 3.33 2.0 6 0.064 -0.53 4 1.94 1.8 8 2.98 2.8 4 3.32 2.3 7 0.062 -0.27 4 1.94 1.8 8 2.98 2.9 4 3.32 2.0 8 0.060 -0.17 4 1.94 1.8 8 2.98 2.7 4 3.32 2.4 9 0.057 0.10 4 1.94 1.8 8 2.98 2.7 4 3.32 2.6
Co···C/N Co···C/N Co···N···C * Co···C···C * n r σ² n r σ² n r σ² n r σ²
8 8 8 8 8 12
4.31 4.30 4.30 4.11 4.15 4.92
1.4 2.1 1.8 4 4.93 -2.2 4.9 4 4.93 -2.8 16 4.22 2.2 8.2 4 4.93 -2.5 12 4.24 3.1 32 3.99 54.3 2.7 12 4.24 5.0 32 4.03 33.0
* multiscattering (2 legs) with a degeneracy of 2 for the shown paths and untreated σ² values. ' smaller fitting range
4. Mass spectrometric study A. Mass spectra of mono-nitrene species 3P1Ns The full mass spectrum of the mixture of 1P1 and 2Ns is shown in Figure S4-1. The main peak (relative intensity 100%) at 671 corresponds to the starting porphyrin ([1P1]+) (see Figure S4-2 for the simulation), which is probably due to a low conversion towards 3P1Ns and/or decomposition of complex 3P1Ns in the presence of acetonitrile. We also observed a peak at 703 a.u. (Figure S4-3, relative intensity ~20%), which can be simulated as a dioxygen adduct of 1P1 ([1P1 + O2]+). This peak is also present in the MS of pure 1P1 (without addition of 2Ns), and is most probably formed in the mass spectrometer due to traces of oxygen. Another peak at 735 (relative intensity ~5%, not simulated) might correspond to the bis-dioxygen adduct ([1P1 + 2O2]+). The peak at 872 (Figure S4-4, relative intensity 0.5%) corresponds to the mono-nitrene [3P1Ns+H+]+ molecular ion (see main text for discussion). The peak at 1544 (Figure S4-5) corresponds to nitrene 3P1Ns containing an additional moiety of 1P1 ([3P1Ns+1P1+H+]+).
S12
Intens. x105
+MS, 1.7-8.1min #(99-479) 671.1647
2.5
2.0
1.5
1.0
703.1550
0.5
735.1454
872.1634 1544.3319
0.0 400
600
800
1000
Figure S4-1. Full mass-spectrum of the reaction of 1P1 with 2Ns.
S13
1200
1400
1600
m/z
Intens. [%] 100
+MS, 2.5-3.9min #(151-232) 671.1640
80
60
672.1673 40
20
673.1707
0 [%]
(C44H28CoN4), M ,671.16 671.1640
100
80
60
672.1674
40
20 673.1707
0 670.5
671.0
671.5
672.0
672.5
673.0
673.5
674.0
m/z
Figure S4-2. Mass-spectrum of the reaction of 1P1 with 2Ns. Region at 671 and simulation for [C44H28CoN4] (corresponds to [1P1]+).
S14
Intens. [%]
+MS, 2.5-3.9min #(151-232) 703.1540
20
15
704.1573 10
5
705.1604
0 [%]
(C44H28CoN4)O2, M ,703.15 703.1539
100
80
60
704.1572
40
20 705.1606
0 702.5
703.0
703.5
704.0
704.5
705.0
705.5
706.0
m/z
Figure S4-3. Mass-spectrum of the reaction of 1P1 with 2Ns. Region at 703 and simulation for [C44H28CoN4O2] (corresponds to [1P1 + O2]+).
S15
Intens. [%]
+MS, 1.7-8.1min #(99-479) 872.1617
0.5
0.4
0.3
873.1645
0.2
874.1599
0.1
0.0 [%]
C44H28CoN4(C6H4SN2O4), M+nH ,872.16 872.1611
100
80
60
873.1643
40
874.1674
20
875.1710
0 871.5
872.0
872.5
873.0
873.5
874.0
874.5
875.0
875.5
m/z
Figure S4-4. Mass-spectrum of the reaction of 1P1 with 2Ns. Region at 872 and simulation for [C50H33CoN6O4S] (corresponds to [3P1Ns]+).
S16
Intens. [%]
+MS, 1.7-8.1min #(99-479) 1544.3274 1543.3243
2.5
2.0
1545.3300
1.5
1.0
1546.3318 0.5
1547.3330 0.0 [%]
(C44H28CoN4)2(C6H4SN2O4), M+nH ,1543.33 1544.3288
100 1543.3256
80
60
1545.3321
40
1546.3355
20
1547.3390
0 1543
1544
1545
1546
1547
1548
1549
m/z
Figure S4-5. Mass-spectrum of the reaction of 1P1 with 2Ns. Region at 1544 and simulation for [C94H60Co2N10O4S] (corresponds to [3P1Ns + 1P1 + H+]+.
S17
B. Mass spectra of mono-nitrene 3P2troc Similar results were obtained in the ESI-MS spectra recorded for the reaction mixture of 1P2 and 2troc (Figure S4-6), but the relative intensity of the thus observed [3P2troc]+ species (Figure S4-6) is higher than in the case of 3P1Ns. Peaks pertaining to loss of H atoms from the catalyst and oxygen adducts of them are seen (Figure S4-8 to S4-10). The loss of H atoms in these cases can be attributed to the H atoms in the amide arms of catalyst 1P2 which is lost in the conditions of mass measurements. The peak for the mono-nitrene species is shown in Figure S4-11. Most parts of the spectra are dealt with in detail in Figures S4-7 to S4-11. Intens. [%]
1+ (A) 1337.6713
+MS, 1.7-7.2min #(105-434)
80
60
40
20 1+ (B) 1529.5935 1+ (D) 1719.5139
0 500
1000
1500
2000
Figure S4-6. Full mass-spectrum of the reaction of 1P2 with 2troc.
S18
2500
3000 m/z
Figure S4-7. Mass-spectrum of the reaction of 1P2 with 2troc. Region at 1338 and simulations for [C84H94CoN8O4] (corresponds to [1P2– H2]+).
S19
Intens. [%]
+MS, 1.7-7.2min #(105-434)
1+ (A) 1337.6713
1+ (A) 1338.6752
80
60
1+ (A) 1339.6796 40
1335.6566
1336.6600 1+ (A) 1340.6845
20
0 [%]
(C84H92CoN8O4), M ,1335.66 1335.6568
100
1336.6601
80
60
1337.6635
40
20 1338.6668
1339.6702
0 1333
1334
1335
1336
1337
1338
1339
1340
1341
m/z
Figure S4-8. Mass-spectrum of the reaction of 1P2 with 2troc. Region at 1335 and simulations for [C84H92CoN8O4] (corresponds to [1P2– 2H2]+).
S20
Intens. [%]
+MS, 1.7-7.2min #(105-434)
1+ (C) 1353.6669
1+ (C) 1354.6730
12.5
10.0
1+ (C) 1355.6801
7.5
5.0 1+ (C) 1356.7024 1351.6536
1352.6572 1357.7135
2.5
0.0 [%]
(C84H92CoN8O4)O, M ,1351.65 1351.6517
100
1352.6550
80
60
1353.6584
40
20 1354.6618
1355.6651
0 1351
1352
1353
1354
1355
1356
1357
1358
m/z
Figure S4-9. Mass-spectrum of the reaction of 1P2 with 2troc. Region at 1351 and simulations for [C84H92CoN8O5] (corresponds to [1P2– 2H2 + O]+).
S21
Intens. [%]
+MS, 1.7-7.2min #(105-434)
1+ (C) 1353.6669
1+ (C) 1354.6730
12.5
10.0
1+ (C) 1355.6801
7.5
5.0 1+ (C) 1356.7024 1352.6572 1357.7135
2.5
0.0 [%]
(C84H94CoN8O4)O, M ,1353.67 1353.6674
100
1354.6707
80
60
1355.6740
40
20 1356.6774
1357.6808
0 1353
1354
1355
1356
1357
1358
1359
m/z
Figure S4-10. Mass-spectrum of the reaction of 1P2 with 2troc. Region at 1353 and simulations for [C84H94CoN8O5] (corresponds to [1P2– H2 + O]+).
S22
Intens. [%]
+MS, 1.7-7.2min #(105-434) 1529.5935
15.0
1527.5919
12.5
1528.5933
1530.5949 10.0
1531.5945 7.5
5.0
1526.5807 1532.5948
2.5
1533.5947
0.0 [%]
1534.7656
(C84H96CoN8O4)(C3H2Cl3NO2), M-nH ,1527.60 1529.5931
100
1530.5960
1527.5954
1528.5987
80
60 1531.5987
40 1532.5931
20 1533.5962
1534.5995
0 1527
1528
1529
1530
1531
1532
1533
1534
1535
m/z
Figure S4-11. Mass-spectrum of the reaction of 1P2 with 2troc. Region at 1530 and simulation for [C87H97Cl3CoN9O6] (corresponds to [3P2troc – H2 + H+]+). Another peak probably corresponds to [3P2troc – 2H2 + H+]+, but this peak is not intensive enough for any reliable simulation.
C. Mass spectra of bis-nitrene species 5P1Ns Further, we investigated the reaction of imino-iodane 4Ns with 1P1 by means of high-resolution ESI-MS (Figure S4-12). Remarkably, in contrast to the reaction of 1P1 with nosyl azide 2Ns, which only showed formation of the mono-nitrene species 3P1Ns in the MS (Figures S4-1, S4-4), here we observed an intense (relative intensity is ~30%) peak of bis-nitrene 5P1Ns plus a hydrogen atom and a proton [5P1Ns + H + H+]+ (Figure S4-14). This species is likely formed by abstraction of one (or two) hydrogen atom from the co-solvent (acetonitrile) by the nitrene moieties of bis-nitrene species 5P1Ns, followed by protonation (or one-electron oxidation) in the matrix or in the mass spectrometer. Also formation of some mono-nitrene species 3P1Ns [3P1Ns + + H+]+ (relative intensity is ~25%) is observed (Figure S4-13). The latter is present either due to incomplete conversion towards the bis-nitrene or is a fragmentation ion of species 5P1Ns. Bisnitrene 5P1Ns seems to be more reactive than mono-nitrene species 3P1Ns and decays within minutes if acetonitrile is present as a co-solvent used (and needed) in the ESI-MS experiments. When the mass spectra are measured only 4 min after mixing 4Ns with 1P1, most of the peaks of the bis-nitrene species (but not the mono-nitrene species) have disappeared (Figure S4-15). S23
Probably, significant decomposition also occurs after mixing 1P1 with an excess of 4Ns, which did not allow us to assign all the peaks in the spectrum shown in Figure S4-12. Intens. [%]
+MS, 1.1-1.3min #(69-78) 703.1531
80
685.1662
60
752.1696
40
798.1078
903.1432
962.1804
1073.1591
872.1609
615.2527 20
486.0751 1111.1104 1147.3006 0 500
600
700
800
900
1000
1100
1200
m/z
Figure S4-12. Full mass-spectrum of the reaction of 4Ns with 1P1 measured after 1 min after mixing compounds.
Intens. [%]
+MS, 1.1-1.3min #(69-78) 872.1609
25
20
15
873.1635
10
874.1604 5
875.1664
0 [%]
(C44H28CoN4)(C6H4N2O4S), M+nH ,872.16 872.1611
100
80
60
873.1643
40
874.1674 20
875.1709 0 871.5
872.0
872.5
873.0
873.5
874.0
874.5
875.0
875.5
876.0
m/z
Figure S4-13. Mass-spectrum of the reaction of 4Ns with 1P1. Region at 872 and simulation for [C50H33CoN6O4S] (corresponds to mono-nitrene species 3P1Ns [3P1Ns + H+]+). S24
Intens. [%]
+MS, 1.1-1.3min #(69-78) 1073.1591
25
20
1074.1609 15
10
1075.1597
5
0 [%]
(C44H28CoN4)(C6H4N2O4S)2H, M+nH ,1073.16 1073.1581
100
80
1074.1613 60
40
1075.1642
20
1076.1574 1077.1606 0 1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
m/z
Figure S4-14. Mass-spectrum of the reaction of 4Ns with 1P1. Region at 1073 and simulation for [C56H38CoN8O8S2] (corresponds to bis-nitrene species 5P1Ns [5P1Ns + H + H+]). Intens. [%]
+MS, 2.0-3.9min #(122-234) 685.1662
80
703.1531
60
40
20
1147.3012 1131.3066 598.1188
734.1588
903.1434 798.1090
871.1533
962.1801
0 400
500
600
700
800
900
1000
1100
1200
m/z
Figure S4-15. Full mass-spectrum of the reaction of 4Ns with 1P1 measured after 4 min after mixing compounds. Target peaks disappear, probably due to reaction with co-solvent acetonitrile. S25
D. Mass spectra of a mixture of 1P2 + 2Ns Mass spectra corresponding to the mono-nitrene species is obtained on mixing 1P2 with 2Ns. Most relevant part of this spectrum corresponding to the mono-nitrene species and the simulation is shown in Figure S4- 16.
Figure S4-16. Top: Mass spectra of 1P2 with 2Ns region at 1539 corresponds to H2-loss from mono-nitrene species 3P2Ns ([3P2Ns – H2 + H+]+), molecular formula [C90H99CoN10O8S]. The region around and 1563 corresponds to the Na+ adduct of 3P2Ns, [C90H100CoN10O8S+Na+]. Middle: simulation for region at 1563 [C90H100CoN10O8S+Na+]. Bottom: simulation for region at 1539 [C90H99CoN10O8S]. E. Mass spectra of a mixture of 1P2 + 2Ts Mixing of 1P2 with 2Ts also gives the mono-nitrene species (Figures S4- 17 and S4-18). Simulations are performed on the most relevant parts of the spectrum.
Figure S4-17. Mass spectra of a mixture of 1P2 with 2Ts, region around 1339 belonging to 1P2. S26
Figure S4-18. Mass spectra of a mixture of 1P2 with 2Ts, region around 1508 corresponding to H2-loss from mono-nitrene species 3P2Ts ([3P2Ts – H2 + H+]+) with molecular formula [C91H102CoN9O6S] (top) and corresponding simulation for the same (bottom). F. Mass spectra of a mixture of 1P2 + 4Ns As mentioned in the main text, the species obtained on mixing bulkier porphyrin 1P2 with the oxidizing iminoiodane 4Ns, the bis-nitrene species is not obtained according to EPR spectroscopy. Instead a mono-nitrene species is obtained. This was also the case in the mass spectrometric studies. A peak corresponding to the mono-nitrene species of 3P2Ns ([3P2Ns – H2 + H+]+) was obtained (effectively lacking a H atom; see Figure S4-20). In addition to that, a small peak corresponding to the bis-nitrene species was also obtained which is shown in Figure S4-21. The region at 1337 and 1351 is shown in Figure S4-19 and belongs to an O-adduct of the catalyst. The net loss of a hydrogen atom can be explained by having a proton as the charge carrier combined with H2 loss from the amide arms of this catalyst under the ionization conditions of the mass spectrometer.
Figure S4-19. Mass spectra of a mixture of 1P2 + 4Ns, region at 1337 belonging to [1P1 H2]+ and 1351 to [1P1 – H2 + O]+.
S27
Figure S4-20. Mass spectra of 1P2 + 4Ns, region at 1539 belonging to mono-nitrene species 3P2Ns ([3P2Ns – H2 + H+]+) with molecular formula [C90H99CoN10O8S] and simulation for the same.
Figure S4-21. Mass spectra of a mixture of 1P2 + 4Ns, region at 1738 belonging to bis-nitrene species 5P2Ns ([5P2Ns – H2]+) with molecular formula [C96H102CoN12O12S2].
S28
5. Copies of the EPR spectra
Figure S5-1. Left: Disappearance of signals of 1P2 with simultaneous appearance of new signals characteristic for 3P2troc. Right: Spectrum around g = 2.00 showing the cobalt and nitrogen hyperfine structure of species 3P2troc in benzene-d6. The Q-band Davies ENDOR experiment (Figure S5-2) revealed broad features spanning 1-60 MHz. Apart from the characteristic proton signals centered around 52 MHz strong lines are observed around 22 and 12 MHz. The position of these features is consistent with the 59Co hyperfine parameters estimated from the high field EPR spectrum (Figure 3, main text), which are summarized in Table 1. Low frequency contributions (
