In crystallo lattice adaptivity triggered by solid-gas reactions of cationic group 7 pincer complexes

The group 7 complexes [M(κ3-2,6-(R2PO)2C5H3N)(CO)2L][BArF4] [M = Mn, R = iPr, L = THF; M = Re, R = tBu, L = vacant site] undergo in crystallo solid-gas reactivity with CO to form the products of THF substitution or CO addition respectively. There is a large, local, adaptive change of [BArF4] anions for M = Mn, whereas for M = Re the changes are smaller and also remote to the site of reactivity.


S1a. General Considerations
All manipulations, unless otherwise stated, were performed under standard Schlenk line and glovebox (<0.5 ppm O2/H2O) techniques under an argon (BOC, N4.8 purity), carbon monoxide (CK Gases, N3.7 purity) or nitrogen atmosphere. Glassware was dried overnight at 140 °C and flame dried under vacuum before use. Pentane, hexane, CH2Cl2 and toluene were dried using a commercially available Grubbs-type purification system (Innovative Technology) and degassed with three freeze-pump-thaw cycles and stored over 3 Å molecular sieves (CH2Cl2 and toluene) under argon in resealable glass ampoules fitted with PTFE high vacuum stopcocks (Rotaflo HP or J. Young). C6H5F (pre-treated with alumina), 1,2-C6H4F2 (pre-treated with alumina) and CD2Cl2 were dried over CaH2, vacuum transferred, degassed with three freeze-pump-thaw cycles, and stored over 3 Å molecular sieves. Tetrahydrofuran (THF) was dried over Na/benzophenone, distilled, degassed with three freeze-pump-thaw cycles and stored over 3 Å molecular sieves. Na [BAr F 4], 1 i Pr-PONOP, 2 t Bu-PONOP, 3 [Mn( i Pr-PONOP)Br(CO)2] 4 and ReBr(CO)5 5 were synthesised according to literature methods. All other chemicals were from commercial sources and used without further purification. Solution state NMR data were collected on a Bruker AVIIIHD 500 MHz or AVIIIHD 600 MHz Widebore spectrometer at the temperatures specified. The solution 1 H and 13 C{ 1 H} NMR spectra were referenced to the residual solvent peaks. Assignments were aided with 1 H{ 31 P} solution NMR data. 31 P{ 1 H} and 11 B{ 1 H} solution spectra were referenced externally to 85% H3PO4 in D2O and 5% BF3•OEt2 in C6D6, respectively. Solid-state NMR samples were prepared in an argonfilled glovebox by pre-loading 60-100 mg of crushed material into a 4.0 mm zirconia solid-state NMR rotor and sealed with Kel-F, vespel or zirconia caps. Solid-state NMR data were obtained on Bruker Avance III HD spectrometers, operating at 100.63 MHz ( 13 C{ 1 H}), 100.56 MHz ( 13 C{ 1 H}), 162.04 MHz ( 31 P{ 1 H}), 161.99 MHz ( 31 P{ 1 H}) or 376.5 MHz ( 19 F{ 1 H}) at the MAS rates and temperatures specified. All 13 C{ 1 H} CP MAS spectra were referenced to adamantane where the upfield methane resonance was taken to be δC = 29.5 ppm, secondarily referenced to δC(SiMe4) = 0.0 ppm. 31 P{ 1 H} CP MAS spectra were referenced to triphenylphosphine (δP = -9.3 ppm relative to H3PO4) or calcium hydrogen phosphate (δP = 1.4 ppm relative to H3PO4). 19 F{ 1 H} HPDEC MAS spectra were referenced to CF3COOH/H2O (50% v/v, δ -76.54 ppm relative to CFCl3). Solid-state NMR spectra were recorded at varied MAS rates to determine isotropic chemical shifts. Electrospray ionisation mass spectrometry (ESI-MS) was carried out using a Bruker MicrOTOF instrument by Mr Karl Heaton at the University of York. ESI-MS for [Mn( i Pr-PONOP)(THF)(CO)2][BAr F 4] was collected using a modified glovebox directly attached to a Bruker HCT-II ion trap. Elemental

Preparation of [Re( t Bu-PONOP)Br(CO)2]
To an ampoule charged with ReBr(CO)5 (490 mg) was added t Bu-PONOP (485 mg) in 1,2-difluorobenzene (10 mL). The reaction mixture was heated to 95 °C for 18 hours, turning from colourless to bright yellow. The reaction was cooled to room temperature and the volatiles removed under reduced pressure. The yellow solid was washed with pentane (3 x 10 mL), and extracted into diethyl ether (40 mL) and isolated via cannula filtration. The volatiles were removed under reduced pressure and dried in vacuo to yield a bright yellow microcrystalline solid. Yield: 607 mg (70%). Crystals suitable for single-crystal X-Ray diffraction were grown from slow vapour diffusion of pentane into a toluene solution at -30 °C.

Preparation of [Re( t Bu-PONOP)(CO)2][BAr F 4] (3)
A solution of [Re( t Bu-PONOP)Br(CO)2] (400mg) in 1,2difluorobenzene (10 mL) was added dropwise to a solution of Na[BAr F 4] (567 mg) in 1,2-difluorobenzene (10 mL). After several drops of [Re( t Bu-PONOP)Br(CO)2] solution had been added, the reaction mixture rapidly changed from a cloudy white suspension to a bright red cloudy suspension. After complete addition, the reaction mixture was stirred at room temperature for 1 hour, then precipitated with hexane (200 mL). The reaction mixture was cannula filtered and the solids extracted into CH2Cl2 (15 mL). The solution was layered with hexane to yield the product as bright red block-like crystals. Yield: 670 mg (80%).                             F 4] was lightly crushed with a spatula and deposited onto Quantifoil Cu R2/4 grids that had been assembled into autogrid cartridges. Grids were transferred into glass vials and transported to the microscope under an Ar atmosphere. The grids were then conductively cooled to liquid N2 temperature and transferred into the cassette under a blanket of N2 vapour before loading into the TEM.

Data Collection
3DED data were collected at 80 K using a Thermo Scientific Glacios TEM operated at 200 kV and equipped with a Ceta-D camera. In order to obtain a low flux whilst operating the microscope in nanoprobe mode the following illumination conditions were used: gun lens 8, spot size 11, 30 µm C2 aperture. This resulted in a parallel beam of ~1 µm diameter and flux of 0.06 -0.07 e -Å -2 s -1 . A selected area aperture was not used. Data were acquired using EPU-D with the following settings: 2x binning, a rotation speed of 2° s -1 and an exposure time of 0.5 s. 19 datasets were collected from crystals across 2 duplicate grids.

Data Processing
All data were processed with DIALS. 6 Images recorded on the Ceta-D exhibit negative mean background values at high resolution which causes failures in background modelling so a pedestal of 64 ADU was added to every pixel value. The initial detector distance was fixed to 958.5 mm (calibrated using an aluminium powder diffraction calibration grid). 8 datasets were combined resulting in 95.3% complete data to 0.83 Å resolution. The strong reflections from each of the datasets were used for joint refinement of the detector distances and unit cell parameters of each of the 8 datasets. The mean refined detector distance 958.48 (20) mm was identical within error to the initial estimate. The optimal unit cell parameters of the combined dataset were then refined by fitting calculated to observed 2θ values.

Data Solution
The structure was solved ab initio using SHELXT 7 and refined with SHELXL. 8 The electron scattering factors from Peng 9 were used in refinement. Anisotropic ADPs were refined for all non-hydrogen atoms. Hydrogen atoms were geometrically placed at the idealised (internuclear) X-H distances defined in SHELXL for refinement of structures against neutron diffraction data 10 and allowed to ride on their parent atoms during refinement. Three CF3 groups are disordered in the structure and were modelled in two positions with distance (C-F and F-F), similar-ADP and rigid-bond 11 restraints (SADI, SIMU and RIGU instructions) used. No other restraints were applied. An extinction parameter was refined. To convert map values (in Å -2 ) to values of electrostatic potential in eÅ -1 a conversion factor of 47.87801 Å 2 V (International Tables for Crystallography (2006) Volume C section 4.3.1.7) followed by a conversion factor of 1V = 0.069446154 eÅ -1 (based on recommended values from CODATA 2018) was used.

S3. Single-Crystal X-Ray Diffraction
Single-crystal X-Ray diffraction data were collected on a Rigaku SuperNova diffractometer with Cu-Kα (λ = 1.54184 Å) radiation equipped with a nitrogen gas Oxford Cryosystems Cryostream unit 12 at the University of York. Diffraction images from raw frame data were reduced using the CrysAlisPro suite of programmes. The structures were solved using SHELXT 7 and refined by full convergence on F 2 against all independent reflections by fullmatrix least-squares using SHELXL 13 (version 2018/3) through the Olex2 GUI. 14 All nonhydrogen atoms were refined anisotropically and hydrogen atoms were geometrically placed and allowed to ride on their parent atoms. Disorder of the -CF3 groups on the [BAr

S4. SEM Methods
The samples were affixed to an Al stub via a carbon pad and then sputter coated with 5 nm of Cu in a JEOL JFC-2300HR high resolution fine coater, equipped with a JEOL FC-TM20 for thickness control. The SEM images were acquired on a JEOL JSM-7800F prime, equipped with a Schottky (field-assisted) thermionic emitter, at the York JEOL Nanocentre. The signals were collected in an off-axis Everhart-Thornley detector with a positive bias, in LED mode 3, for attraction of both secondary and backscattered electrons. An objective lens aperture size of 30 μm was used with an accelerating voltage of 5 keV, resulting in a probe current of 0.1 nA. At the used working distance of 10 mm, with the aforementioned settings, the maximum resolution of the instrument is 3 nm. The images produced are 1280 x 960 pixels in resolution and were collected with a dwell time of 14 μs at each pixel.

S5ai. Periodic DFT Calculations
Periodic DFT calculations were performed employing the Gaussian Plane Wave (GPW) formalism as implemented in the QUICKSTEP 15 module within the CP2K program suite (Version 5.0). 16  4], 4, were obtained from the experimental crystallographic data. For structure 1 the hexane molecule present in the experimental unit cell was removed and periodic DFT optimizations resulted in good agreement with the experimental structure (see Figure S43) The proto-structures 2* and 4* were generated from the unit cell of structures 1 and 3 via THF/CO substitution and CO addition at all metal centres respectively. Periodic boundary conditions (PBC) were applied throughout in combination with fixed unit cell parameters obtained from experiment. Molecularly optimized basis sets of double-ζ quality plus polarization in their short-range variant (DZVP-MOLOPT-SR-GTH) 17 were used on all atomic species. The interaction between the core electrons and the valence shell (Mn: 15, Re: 15, F: 7, O: 6, N: 5, P: 5, C: 4, B: 3, H: 1 electrons) was described by Goedecker-Teter-Hutter (GTH) pseudo potentials. [18][19][20] Geometry optimisations employed the PBE GGA functional 21 and included dispersion effects via Grimme's D3 correction. 22 The auxiliary plane wave basis set was truncated at a cutoff of 500 Ry. The maximum force convergence criterion was set to 10 -4 Eh·Bohr -1 , whilst default values were used for the remaining criteria. The convergence criterion for the self-consistent field (SCF) accuracy was set to 10 −7 Eh and 10 -8 Eh for geometry optimizations. The electronic energies were used directly without further corrections. The Brillouin zone was sampled using the Γ-point.
Cartesian coordinates in Å of the central cations surrounded by the arrays of anions are provided as a separate XYZ file. Individual ion-pair geometries were taken from these structures without further modification. Good agreement between computed and experimental structures were obtained (see Figures S43-S46).

S5aii. Computational Details for Molecular DFT Calculations
Inter-ion interactions were analysed between one central metal cation and five nearestneighbour surrounding [BAr F 4] anions, where ion-pair geometries were extracted from the periodic-DFT optimised structures. The ion-pair interaction energies were computed using Gaussian16 (Revision A.03) and employed the PBE functional with and without Grimme's D3 dispersion correction. 23 Mn and Re centres were described with Stuttgart pseudopotentials and associated basis sets 24 while 6-31G** basis sets were employed for the other atoms. 25,26 The transition state for CO exchange in the [Re( t Bu-PONOP)(CO)2] + system was modelled and verified by the appearance of one imaginary frequency in the vibrational analysis. IRC calculations showed this transition state linked to two equivalent forms of the ground state structure, i.e. the [Re( t Bu-PONOP)(CO)2] + cation. Quantum theory of atoms in molecules (QTAIM) analysis 27 employed AIMALL program 28 and used the extended wavefunction format. Independent gradient model calculations were run with Multiwfn 29 with the Hirshfeld partitioning scheme (IGMH method). 30 Surfaces were visualised with VMD. 31

S5b. QTAIM Analysis of the [Re(tBu-PONOP)(CO)2]+ molecular cation
The molecular graph for this species is shown in Figure S42 with bond critical points (BCPs) shown as green spheres. Bond paths with ρ(r) < 0.001 a.u. and ring critical points are omitted for clarity. Bond paths signalling weak HH and OH interactions were seen (see table of associated BCP metrics) but no evidence for any C-HRe bond paths that would be associated with an agostic interaction was computed. Note that the atom labelling scheme provided here differs to that in the main manuscript.     Figure S49: IGMH plots for IP1-IP5 in 3 and its equivalent in 4* after THF/CO substitution. Cations and anions are defined as separate fragments; sign(λ2)ρ-coloured isosurfaces are plotted with δG inter = 0.003 a.u; relative atomic contributions coloured by %δG atom . The ion-pair interaction energies are also indicated (kcal/mol) with the contribution from dispersion in brackets.