Application of NMR crystallography to the determination of the mechanism of charge-balancing in organocation-templated AlPO STA-2

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1 Application of NMR crystallography to the determination of the mechanism of charge-balancing in organocation-templated AlPO STA-2 Valerie R. Seymour, Eike C. V. Eschenroeder, Maria Castro, Paul A. Wright and Sharon E. Ashbrook* Supplementary Information S1. Synthesis of STA-2(BDAB) S2. Referencing of CASTEP calculations S3. 27 Al MQMAS spectra of as-made STA-2(BDAB) S4. D-HMQC NMR spectrum of as-made STA-2(BDAB) S5. NMR spectra of dehydrated as-made STA-2(BDAB) S6. Calculated NMR parameters for STA-2(BDAB) S7. Comparison of DFT calculations and experimental MQMAS spectra S8. DFT calculations of J-HETCOR spectra of STA-2(BDAB) S9. Calculated 13 C and 15 N NMR parameters for STA-2(BDAB) S10. References 1

2 S1. Synthesis of STA-2(BDAB) Bis-DABCO-butane, BDAB, was prepared according to literature methods.[s1,s2] The dibromoalkane and amine were mixed in a 1 : 2 molar ratio and refluxed at 80 ºC in ethanol for 5 h. Once cool, excess ethanol was removed on a rotary evaporator and the residue allowed to crystallise overnight under refrigeration to give a white solid. This was washed with acetone, cold ethyl acetate and acetonitrile. The product bromides were allowed to dry at room temperature in air. The typical yield of both templates was 97%. In a typical hydrothermal synthesis of AlPO STA-2, 0.74 g (0.80 mmol) Al(OH)3.0.8H2O and 0.93 g H3PO4 (0.81 mmol, 85% in H2O) were stirred in a beaker g (3.5 mmol) of the BDABBr2 template was anion-exchanged by stirring the aqueous solution with excess Amberlite IRN78 resin for 12 h at room temperature. The template solution was rotary evaporated to 5.5 ml, added to the reaction gel and was stirred for 4 h at room temperature. The homogenous gel (ph 7, molar ratio 0.99 : 1.00 : 0.44 : respectively) was put into a stainless steel, PTFE-lined autoclave and heated without stirring at 190 C for 48 h. After slow cooling, the product was sonicated and filtered off. Figure S1.1 shows electron microscope images of the STA-2 single crystals obtained. All reagents have been obtained from Sigma-Aldrich, except H3PO4, which has been obtained from Prolabo. Figure S1.1 Electron microscope images of the AlPO STA-2 single crystals obtained. 2

3 S2. Referencing of CASTEP calculations CASTEP[S3] DFT calculations generate the absolute shielding tensor ( ) in the crystal frame. The isotropic chemical shift, iso, is related to the isotropic component of by iso = ( iso ref), (S2.1) where iso is (1/3) Tr{ }, and ref is the reference shielding. Experimentally, ref is obtained by measuring the chemical shift of an external reference sample. For the DFT calculations, ref was determined by taking the average of the ref values calculated for the two Al and two P species in calcined STA-2. These calculations were carried out on optimised structures using CASTEP version 5.5.2, a planewave energy cutoff of 50 Ry and a k-point spacing of 0.04 Å 1. The results are given in Table S2.1. Table S P and 27 Al calculated isotopic shieldings and experimental chemical shifts[s4] for calcined STA-2, and the reference shieldings determined. STA-2 iso calc (ppm) iso exp (ppm) ref (ppm) ref> (ppm) P P Al Al

4 S3. 27 Al MQMAS spectra of as-made STA-2 27 Al triple-quantum MAS NMR spectra of as-made STA-2(BDAB) were acquired using split-t1 shifted echo experiments (as in previous work[s4]) and z-filtered experiments, in order to ensure that broadened resonances are acquired accurately and that no signal is lost completely as a result of T2 relaxation during the echo period. The two spectra acquired with B0 = 14.1 T are shown in Figure S3.1 (with appropriate shearing in the case of the z-filtered spectrum). Two broadened resonances corresponding to fourcoordinate Al are resolved, and are presumed to arise from species that correspond to Al1 and Al2 in the calcined form (i.e., in S6R and D6R respectively), although these cannot be assigned simply from the spectrum. A distinct shoulder is observed between the two, indicating perhaps some form of ordering. Only one (broadened) resonance is observed in the five-coordinate region of the spectrum. Average NMR parameters for these resonances are given in Table 3 of the main text. The integrated intensities of the two major Al IV resonances is 1 : 1, suggesting that a similar number of bridging hydroxyls are attached to both Al1 and Al2. 4

5 Figure S3.1 Two-dimensional 27 Al (14.1 T, 14 khz) triple-quantum MAS NMR spectra of STA-2(BDAB), acquired using (a) a phase-modulated split-t1 shifted echo experiment and (b) a z-filtered experiment. The spectrum in (b) is shown after a shearing transformation. The MAS spectrum is shown above each two-dimensional spectrum for comparison. 5

6 S4. D-HMQC NMR spectrum of as-made STA-2(BDAB) Figure S4.1 shows a two-dimensional 27 Al/ 31 P D-HMQC[S5] spectrum acquired at B0 = 18.8 T. This spectrum, exploiting transfer via the heteronuclear dipolar interaction using the SFAM[S6] dipolar recoupling sequence, is able to provide information on species that are in close spatial proximity. It can be compared directly with the J-HETCOR spectra in the main text (although note the reversal of the axes), which exhibit cross peaks between species that are linked through covalent bonds. While the two types of spectra show very similar cross peaks for the major resonances, the D-HMQC spectrum additionally shows cross peaks between the broad, low intensity resonances in the 27 Al and 31 P spectra. This appears to confirm them as resulting from the same less crystalline impurity phase (as no cross peaks are observed for either of these resonances and those from STA-2(BDAB). Figure S4.1 Two-dimensional 27 Al/ 31 P (18.8 T, 20 khz) D-HMQC NMR spectra of STA- 2(BDAB), acquired using SFAM dipolar recoupling. The shaded area indicates cross peaks corresponding to an impurity phase. 6

7 S5. NMR spectra of dehydrated as-made STA-2(BDAB) STA-2 is known to absorb water in its as-made form.[s4] However, there were no significant changes in the 27 Al and 31 P spectra of a sample of STA-2(BDAB) dried at 250 C for 3 h (shown in Figures S5.1a and b), suggesting that the water is present only within the pores and is not coordinated to the framework Al species. A comparison of the 1 H MAS NMR spectra (Figure S5.1c) reveals a decrease in intensity of the resonance at ~ 5 ppm upon drying, confirming water was present in the pores initially. (The residual intensity at 5 ppm in the spectrum of the dried material probably results from the hydroxyl protons). Figure S5.1 (a) 27 Al, (b) 31 P and (c) 1 H MAS NMR spectra of as-made and dried STA- 2(BDAB), acquired at 14.1 T with MAS rates of (a, b) 10 khz and (c) 60 khz. A two-dimensional 27 Al/ 31 P J-HETCOR spectrum of the dried material, also acquired at 14.1 T, shows no differences to that of the hydrated as-made material (as shown in Figure S5.2), confirming that the framework structure (and, therefore, the NMR parameters) are relatively unaffected by the presence of water. 7

8 Figure S5.2 Two-dimensional 27 Al/ 31 P J-HETCOR NMR spectra (14.1 T, 10 khz) of (a) as-made and (b) dried STA-2(BDAB), acquired using = 2.5 ms. 8

9 S6. Calculated NMR parameters for STA-2(BDAB) Table S6.1 shows the 27 Al and 31 P NMR parameters calculated using nine possible structural models described in the main text, with the position of hydroxyl oxygens O91- O96 shown in Figure 4a. Table S Al and 31 P calculated (using CASTEP) NMR parameters (isotropic chemical shift, iso, quadrupolar coupling constant, CQ and asymmetry, Q) for optimised structural models of STA-2(BDAB). iso (ppm) CQ /MHz Q iso (ppm) O91O92 Al11 Al IV / S6R P11 D6R Al12 Al IV / S6R P12 D6R Al13 Al IV / S6R P13 D6R Al14 Al V / S6R P14 D6R Al15 Al IV / S6R P15 D6R Al16 Al V / S6R P16 D6R Al21 Al IV / D6R P21 S6R Al22 Al IV / D6R P22 S6R Al23 Al V / D6R P23 S6R* Al24 Al IV / D6R P24 S6R Al25 Al V / D6R P25 S6R* Al26 Al IV / D6R P26 S6R O91O93 Al11 Al IV / S6R P11 D6R Al12 Al V / S6R P12 D6R Al13 Al IV / S6R P13 D6R

10 Al14 Al V / S6R P14 D6R Al15 Al IV / S6R P15 D6R Al16 Al IV / S6R P16 D6R Al21 Al V / D6R P21 S6R* Al22 Al IV / D6R P22 S6R Al23 Al V / D6R P23 S6R* Al24 Al IV / D6R P24 S6R Al25 Al IV / D6R P25 S6R Al26 Al IV / D6R P26 S6R O91O94 Al11 Al V / S6R P11 D6R Al12 Al IV / S6R P12 D6R Al13 Al IV / S6R P13 D6R Al14 Al V / S6R P14 D6R Al15 Al IV / S6R P15 D6R Al16 Al IV / S6R P16 D6R Al21 Al IV / D6R P21 S6R Al22 Al V / D6R P22 S6R* Al23 Al V / D6R P23 S6R* Al24 Al IV / D6R P24 S6R Al25 Al IV / D6R P25 S6R Al26 Al IV / D6R P26 S6R O91O95 Al11 Al IV / S6R P11 D6R Al12 Al IV / S6R P12 D6R Al13 Al V / S6R P13 D6R Al14 Al V / S6R P14 D6R Al15 Al IV / S6R P15 D6R

11 Al16 Al IV / S6R P16 D6R Al21 Al IV / D6R P21 S6R Al22 Al IV / D6R P22 S6R Al23 Al V / D6R P23 S6R* Al24 Al V / D6R P24 S6R* Al25 Al IV / D6R P25 S6R Al26 Al IV / D6R P26 S6R O91O96 Al11 Al IV / S6R P11 D6R Al12 Al IV / S6R P12 D6R Al13 Al IV / S6R P13 D6R Al14 Al V / S6R P14 D6R Al15 Al V / S6R P15 D6R Al16 Al IV / S6R P16 D6R Al21 Al IV / D6R P21 S6R Al22 Al IV / D6R P22 S6R Al23 Al V / D6R P23 S6R* Al24 Al IV / D6R P24 S6R Al25 Al IV / D6R P25 S6R Al26 Al V / D6R P26 S6R* O92O93 Al11 Al IV / S6R P11 D6R Al12 Al V / S6R P12 D6R Al13 Al IV / S6R P13 D6R Al14 Al IV / S6R P14 D6R Al15 Al IV / S6R P15 D6R Al16 Al V / S6R P16 D6R Al21 Al V / D6R P21 S6R*

12 Al22 Al IV / D6R P22 S6R Al23 Al IV / D6R P23 S6R Al24 Al IV / D6R P24 S6R Al25 Al V / D6R P25 S6R* Al26 Al IV / D6R P26 S6R O92O94 Al11 Al V / S6R P11 D6R Al12 Al IV / S6R P12 D6R Al13 Al IV / S6R P13 D6R Al14 Al IV / S6R P14 D6R Al15 Al IV / S6R P15 D6R Al16 Al V / S6R P16 D6R Al21 Al IV / D6R P21 S6R Al22 Al V / D6R P22 S6R* Al23 Al IV / D6R P23 S6R Al24 Al IV / D6R P24 S6R Al25 Al V / D6R P25 S6R* Al26 Al IV / D6R P26 S6R O92O95 Al11 Al IV / S6R P11 D6R Al12 Al IV / S6R P12 D6R Al13 Al V / S6R P13 D6R Al14 Al IV / S6R P14 D6R Al15 Al IV / S6R P15 D6R Al16 Al V / S6R P16 D6R Al21 Al IV / D6R P21 S6R Al22 Al IV / D6R P22 S6R Al23 Al IV / D6R P23 S6R

13 Al24 Al V / D6R P24 S6R* Al25 Al V / D6R P25 S6R* Al26 Al IV / D6R P26 S6R O92O96 Al11 Al IV / S6R P11 D6R Al12 Al IV / S6R P12 D6R Al13 Al IV / S6R P13 D6R Al14 Al IV / S6R P14 D6R Al15 Al V / S6R P15 D6R Al16 Al V / S6R P16 D6R Al21 Al IV / D6R P21 S6R Al22 Al IV / D6R P22 S6R Al23 Al IV / D6R P23 S6R Al24 Al IV / D6R P24 S6R Al25 Al V / D6R P25 S6R* Al26 Al V / D6R P26 S6R*

14 S7. Comparison of DFT calculations and experimental MQMAS spectra Figure S7.1 shows the predicted centre-of-gravity ( 1, 2) of resonances in a 27 Al MQMAS NMR spectrum, for each of the Al species in the calculated models of STA- 2(BDAB). The 2 position is simply a sum of the 27 Al isotropic chemical and second-order quadrupolar shifts, whereas the position in 1 is determined (for a sheared (or split-t1) triple-quantum MAS spectrum) by 1 = (17/31) iso + (32/93) Q (for I = 5/2, using the scaling convention of Ref. S7). 14

15 Figure S7.1 Plots of the resonance position (i.e., centre-of-gravity (( 1, 2)) in 27 Al (14.1 T) MQMAS NMR spectra for Al species in the range of structural models of STA- 2(BDAB), using the calculated NMR parameters given in Table S6.1. Also shown is the experimental spectrum (14.1 T) of STA-2(BDAB) for comparison. 15

16 S8. DFT calculations of J-HETCOR spectra of STA-2(BDAB) Figure S8.1 shows the predicted position of cross peaks in a 27 Al/ 31 P (20.0 T) J- HETCOR spectrum for each of the structural models of STA-2(BDAB). These plots were generated by correlating the 31 P and 27 Al isotropic chemical shifts, i.e., the isotropic quadrupolar shift for 27 Al is not included, for all species joined by a single Al-O-P linkage. The Al and P species linked by two bonds are shown in Table 5 in the main text. 16

17 Figure S8.1 Plots of cross peak position in 27 Al/ 31 P (20.0 T) J-HETCOR NMR spectra for structural models of STA-2(BDAB), using only the calculated isotropic chemical shifts (i.e., no isotropic quadrupolar shift) given in Table S6.1. Also shown is the experimental spectrum (20.0 T) of STA-2(BDAB) for comparison. 17

18 S9. Calculated 13 C and 15 N NMR parameters for STA-2(BDAB) Figure S9.1 Labeling scheme used for the BDAB template molecule in STA-2(BDAB). Table S9.1 Experimental 13 C and 15 N isotropic chemical shifts, iso exp, for STA-2(BDAB). Reproduced from Ref. S4. Species iso exp (ppm) Species iso exp (ppm) C N C N C C

19 Table S9.2 Calculated 15 N isotropic chemical shifts, iso calc, for structural models of STA- 2(BDAB). 15 N iso calc (ppm)* N1 N2 O91O , , , , O91O , , , , O91O , , , , O91O , , , , O91O , , , , O92O , , , , O92O , , , , O92O , , , , O92O , , , , *Referenced to quaternary N (N2) in the experimental 15 N MAS NMR spectrum in Ref. S4 at ppm 19

20 Table S9.3 Calculated 13 C isotropic chemical shifts, iso calc, for structural models of STA- 2(BDAB). Species 13 C iso calc (ppm)* O91O92 O91O93 O91O94 O91O95 O92O93 O92O94 O92O95 O92O96 C C C C C C C C C C C C C C C C *Referenced to C2 in the experimental 13 C MAS NMR spectrum in Ref. S4 at 64.6 ppm 20

21 S10. References S1. T. P. Abbiss, F. G. Mann, J. Chem. Soc. 1964, S2. G. W. Noble, P. A. Wright, A. Kvick, J. Chem. Soc. Dalton. Trans. 1997, S3. M. D. Segall, P. J. D. Lindan, M. J. Probert, C. J. Pickard, P. J. Hasnip, S. J. Clark, M. C. J. Payne, J. Phys.: Condens. Matter., 2002, 14, S4. M. Castro, V. R. Seymour, D. Carnevale, J. M. Griffin, S. E. Ashbrook, P. A. Wright, D. C. Apperley, J. E. Parker, S. P. Thompson, A. Fecant, N. Bats, J. Phys. Chem., 2010, 114, S5. G. Tricot, O. Lafon, J. Trebosc, L. Delevoye, F. Mear, L. Montagne, J. P., Phys. Chem. Chem. Phys., 2011, 13, S6. R. Fu, S. A. Smith, G. Bodenhausen, Chem. Phys. Let. 1997, 272, 361. S7. K. J. Pike, R. Malde, S. E. Ashbrook, J. McManus, S. Wimperis, Solid State Nucl. Magn. Reson., 2000, 16,