Supporting Information. Post-synthetic modification of molecular frameworks using click chemistry: the importance of strained C-C triple bonds

Transcription

1 Supporting Information Post-synthetic modification of molecular frameworks using click chemistry: the importance of strained C-C triple bonds Zhengbang Wang, Jinxuan Liu, Hasan K. Arslan, Sylvain Grosjean, Tobias Hagendorn, Hartmut Gliemann, Stefan Bräse,,# and Christof Wöll *, Institute of Functional Interfaces, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany Soft Matter Synthesis Lab, Institute of Biological Interfaces, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany. Institute of Organic Chemistry, Karlsruhe Institute of Technology, Karlsruhe, Germany # Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany. S 1

2 In the supporting information we provide first a description of the equipment used for the characterization of the MOF thin films, or SURMOFs, fabricated in the course of this work and then provide XRD, EDX and IR-data recorded for the films. These data allow to judge the quality of the films and to determine the efficiency of the PSM process. General methods. All the reagents and solvents (except N 3 -BDC, compound 1 and compound 2 for metal-free click reaction) employed here were commercially available and used as supplied without further purification. The samples were characterized with infra red reflection absorption spectroscopy (IRRAS) and X-ray diffraction (XRD). IRRAS data were recorded using a Biorad Excalibur FTIR spectrometer (FTS 3000) equipped with a grazing incidence reflection unit (Biorad Uniflex) and a narrow band MCT detector. X-ray diffraction (XRD) measurements for out-of-plane (co-planar orientation) were carried out using Bruker D8-Advance diffractometer equipped with a position sensitive detector (PSD) Lynxeye in θ-θ geometry, variable divergence slit and 2.3 Soller-slit was used on the secondary side. XRD measurements for in-plane (non-coplanar orientation) were carried out using Bruker D8 Discover equipped with a quarter Eulerian cradle, tilt-stage and 2.3 Soller-slits were installed in both sides. A Göbel-mirror, and a PSD Lynxeye in θ-2θ geometry, were applied in the measurement. The Cu-anodes which utilize the Cu Kα1, 2-radiation (λ= nm) was used in both instrument. The measurement was carried out in the range of 2θ = 5-20 at a scan step of 0.02 at 40 kv and 30 ma. ImageJ software with a Dropsnake plugin was used to measure the water contact angle. The fluorescence properties of the SURMOFs was measured with a Fluorescence Microscope equipped with a mercury short arc reflector lamp (Type HXP-R 120W/45C VIS), Supplier: OSRMA and the band pass filter (BP) with BP 546/12 and the long pass (LP) filter LP 590 were separately used for the excitation and emission filters. The thickness of the MOFs thin films before and after PSM was measured by ellipsometry (J. A. Woolam Co., Inc.; WVASE32 software) and modeled as a Cauchy S 2

3 layer. On each sample surface, at least three spots were measured and the mean film thickness was calculated assuming a Cauchy layer. The loading of the SURMOFs with methanol was determined by gas-phase QCM using Zn 2 (N 3 -bdc) 2 (dabco)] SURMOFs grown on QCM gold substrates modified with a MUD SAM. Prior to the QCM measurements the SURMOF sample was activated at 80 C for 4 h under a flow of pure nitrogen to remove any residual solvent hosted in MOFs. Before switching to the vessel containing methanol, pure nitrogen gas (carrier gas) was passed over the SURMOFs sample to obtain a stable baseline. The adsorption curve was recorded at 25 C using a flow rate of 100 sccm. A Bruker Tensor 27 Fourier transform IR spectrometer (Bruker Optik GmbH, Ettlingen, Germany), with a Bruker Platinum Attenuated total reflectance (ATR) cell, was employed to obtain the IR spectra of dabco linkers which were available in adequate amount. The cell was equipped with an ATR crystal made from diamond, onto which the samples were pressed directly. A total of 32 scans in the cm 1 spectral range were recorded with a scan velocity of 10 khz and a spectral resolution of 4 cm 1. The reference spectra were acquired with the unloaded diamond crystal. N 3 -BDC was characterized with nuclear magnetic resonance (NMR) spectroscopy, high resolution mass spectrometry (HRMS), and infra-red spectroscopy (IR). NMR spectra were recorded on a Bruker AM 500 spectrometer (500 MHz for 1 H / 125 MHz for 13 C), as solutions in DMSO-d 6. Chemical shifts, δ, were quoted in parts per million (ppm) and were referenced to DMSO as internal standard. The following abbreviations were used to describe peak patterns when appropriate: br = broad, s = singlet, d = doublet and m = multiplet. Coupling constants, J, are reported in Hertz unit (Hz). Mass spectra were recorded with a Finnigan MAT 95 (70 ev) spectrometer under electron impact (EI) conditions. The molecular fragments were quoted as the relation between mass and charge (m/z). The abbreviation [M + ] refers to the molecular ion. IR spectrum was recorded with a FTIR Bruker IFS 88 spectrometer, S 3

4 using the attenuated total reflection technique (ATR). The absorption band positions are given in wave numbers ν in cm 1. Figure S1 Schematic diagram for the automated LBL growth of MOFs thin films on substrates functionalized with SAMs. The preparation is done by repeated immersion cycles first in solution of the metal precursor (1 mm ethanolic solution of zinc acetate hydrate) and subsequently in the ethanolic organic ligand solution (0.2 mm equimolar N 3 -bdc/dabco mixture), with rinsing in ethanol between the two steps. (Journal of the American Chemical Society 2011, 133, 8158). S 4

5 Figure S2 IR spectra recorded for a 40 cycle [Zn 2 (N 3 -bdc) 2 (dabco)] MOF thin film grown on the OH-terminated organic surface of a MUD-SAM supported by an Au-substrate. S 5

6 Table S1 Peak assignment for IR spectra (Figure S2) S 6

7 Figure S3 IR data of a 40 cycle [Zn 2 (N 3 -bdc) 2 (dabco)] MOF thin film before and after activation at 80 C for 4 h. S 7

8 Figure S4 XRD data of a 40 cycles of [Zn 2 (N 3 -bdc) 2 (dabco)] MOF thin films before and after activation at 80 C for 4 h. S 8

9 Figure S5 IR data of a 40 cycles of [Zn 2 (N 3 -bdc) 2 (dabco)] MOF thin films before and after separately soaking in THF and dichloromethane for 4 h and 2 h. S 9

10 Figure S6 XRD data of a 40 cycles of [Zn 2 (N 3 -bdc) 2 (dabco)] MOF thin films before and after separately soaking in THF and dichloromethane for 4 h and 2 h S 10

11 Figure S7 IR data of a 40 cycles of [Zn 2 (N 3 -bdc) 2 (dabco)] MOF thin films before and after soaking in THF with catalyst for 4 h. S 11

12 Figure S8 XRD data of a 40 cycles of [Zn 2 (N 3 -bdc) 2 (dabco)] MOF thin films before and after soaking in THF with catalyst for 4 h. S 12

13 Figure S9 IR data recorded for a 40 cycle [Zn 2 (N 3 -bdc) 2 (dabco)] MOF thin film before and after soaking in THF with phenylacetylene for 4 h. S 13

14 Figure S10 XRD data of a 40 cycles of [Zn 2 (N 3 -bdc) 2 (dabco)] MOF thin films before and after soaking in THF with phenylacetylene for 4 h. S 14

15 Figure S11 QCM data recorded during the uptake of methanol from the gas phase into Zn 2 (N 3 -bdc) 2 (dabco)] SURMOFs before (black) and after (red) post-synthetic modifications with phenylacetylene. The thicknesses of the SURMOFs before and after PSM as determined by ellipsometry amount to 24.0 nm and 26.0 nm, respectively. From the total area of the QCM gold substrate, the MOF lattice parameter and the uptake amount as recorded by QCM, we obtain an average loading of 0.7 methanol molecules per unit cell for the pristine sample and of 0.2 methanol molecules per unit cell for the sample after PSM with phenylacetylene. S 15

16 Figure S12 EDX data of [Zn 2 (N 3 -bdc) 2 (dabco)] MOF thin films after Cu-catalyst click reaction, followed by soaking in ethanol under ultrasonic for 4 h. S 16

17 Figure S13 Schematic illustration of Cu-catalyst click reaction carried out on the surface of the MOFs. S 17

18 Figure S14 IR spectroscopy of: (a) 40 cycle [Zn 2 (bdc) 2 (dabco)] SURMOF; (b) N 3 -BDC functionalized [Zn 2 (bdc) 2 (dabco)] SURMOF; (c) N 3 -BDC functionalized [Zn 2 (bdc) 2 (dabco)] SURMOFs after carrying out the Cu-catalyst click reaction with an hydrophobic molecule (1-ethynyl-4-pentylbenzene) for 1 h. S 18

19 Figure S15 IR spectroscopy of: (a) 40 cycle [Zn 2 (bdc) 2 (dabco)] SURMOF; (b) N 3 -BDC functionalized [Zn 2 (bdc) 2 (dabco)] SURMOF; (c) N3-BDC functionalized [Zn 2 (bdc) 2 (dabco)] SURMOF after carrying out the Cu-catalyst click reaction with a fluorescence molecule (Alkyne MegaStokes dye 673) for 1 h. S 19

20 Figure S16 Comparison of XRD patterns from as-synthesized [Zn 2 (N 3 -bdc) 2 (dabco)] (black), prepared by the LPE method, and after reaction with compound 1 (red). S 20

21 Figure S17 Comparison of XRD patterns from as-synthesized [Zn 2 (N 3 -bdc) 2 (dabco)] (black), prepared by the LPE method, and after reaction with compound 2 shown in the inset (red). S 21

22 In this study, the PSM of [Zn 2 (N 3 bdc) 2 (dabco)] MOFs thin films using click-chemistry was monitored by IRRAS. In all cases, a decrease of the N 3 vibration was observed with increasing reaction times. Of course, the PSM process in which additionally molecules are coupled into the framework, should lead to the appearance of new vibrations. For example, coupling the (1-ethynyl-4-pentylbenzene) should lead to the appearance of a CH 3 vibration. Unfortunately, in case of [Zn 2 (N 3 bdc) 2 (dabco)] SURMOFs a vibration at 2965 cm -1 (originating from the dabco-compound) is present already before the PSM-process, thus obscuring the CH 3 -vibration Figure S18 IR spectroscopy of: (a) 40 cycle [Zn 2 (bdc) 2 (dabco)] SURMOF; (b) N 3 -BDC functionalized [Zn 2 (bdc) 2 (dabco)] SURMOF; (c) N 3 -BDC functionalized [Zn 2 (bdc) 2 (dabco)] SURMOFs after carrying out the Cu-catalyst click reaction with an hydrophobic molecule (1-ethynyl-4-pentylbenzene) for 1 h. S 22

23 Figure S19 PSM of highly oriented [Cu 2 (N 3 -bdc) 2 (dabco)] MOF thin films prepared with Cu(CF 3 COO) 2 was monitored by IRRAS at different reaction times and the IR spectrum of pure dabco linkers measured using an Attenuated Total Reflectance (ATR) setup. A yield of % was calculated from the maximum absorbance of the N 3 stretching vibration (2112 cm 1 ) after reaction with 1-ethynyl-4-pentylbenzene for 8 h. S 23

24 Figure S20 IRRAS data for pristine [Zn 2 (bdc) 2 (dabco)] SURMOFs (black curve) and after click reaction with 1-ethynyl-4-fluorobenzene for 2h (red curve), 4h (blue curve) and 6h (dark cyan curve); ATR spectra for pure 1-ethynyl-4-fluorobenzene; inset: 5 times magnifying IR spectroscopy from 1180 cm -1 to 1280 cm -1. A yield of 93.4 % was calculated from the maximum absorbance of the N 3 stretching vibration (2114 cm 1 ) after reaction with 1-ethynyl-4-fluorobenzene for 6 h. S 24

25 Table S2 The yields of the functionalization of SURMOFs in volume with different alkyne reactants by using (I)-catalyzed click chemistry or strain-promoted click chemistry. S 25