Insight into Fast Nucleation and Growth of Zeolitic Imidazolate

Article pubs.acs.org/crystal

Insight into Fast Nucleation and Growth of Zeolitic Imidazolate Framework-71 by In Situ Time-Resolved Light and X‑ray Scattering Experiments Sanjib Saha,† Sergej Springer,‡ Maria E. Schweinefuß,‡ Diego Pontoni,§ Michael Wiebcke,*,‡ and Klaus Huber*,† †

Department Chemie, Universität Paderborn, Warburger Strasse 100, 33098 Paderborn, Germany Institut für Anorganische Chemie, Leibniz Universität Hannover, Callinstrasse 9, 30167 Hannover, Germany § European Synchrotron Radiation Facility, 38043 Grenoble Cedex, France ‡

S Supporting Information *

ABSTRACT: The current rather poor understanding of the mechanisms of crystallization of zeolitic imidazolate frameworks (ZIFs), an important subclass of porous metal organic framework (MOF) materials, greatly hampers rational synthesis of predicted ZIF phases/polymorphs and control of crystal size/shape. In this contribution, we present the results of in situ studies on a recently developed fast ZIF-71 nanocrystal synthesis from solution. By taking advantage of the combined use of time-resolved static and dynamic light scattering and stopped-flow synchrotron small-angle and wide-angle X-ray scattering, we were able to reveal the whole nanocrystal formation process: a population of small amorphous particles (termed clusters) first forms via coagulation, followed by the formation of a second population of bigger amorphous particles that grow via addition of significantly smaller “monomers”, the nature of which remains as yet unknown (clusters and/or smaller units). The latter particles transform into the periodic ZIF-71 structure with RHO topology, probably via intraparticle nucleation and subsequent particle reorganization. The reaction kinetics speeds up with increasing linker-tometal concentration ratio, yielding nanocrystals with decreasing size, while the life times of amorphous intermediates become very short and challenging to be observed experimentally. We discuss how our results complement and extend recent findings on the crystallization of ZIF-8 with SOD topology under similar synthetic conditions.

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INTRODUCTION Zeolitic imidazolate frameworks (ZIFs) are a distinctive subclass of metal organic frameworks (MOFs).1 Their periodic tetrahedral framework structures with underlying zeolite-related topologies are assembled from divalent metal cations and linking imidazolate and/or substituted imidazolate anions.2,3 Currently, microporous ZIFs are attracting tremendous attention for many potential applications in fields such as separation and catalysis, because ZIFs, due to the modifiable imidazolate linker, are more easily tunable toward specific applications than pure, inorganic zeolites.2,3 In addition, some ZIFs exhibit good water stability4,5 unlike most other MOFs.6 More than 100 ZIFs with about 30 different underlying net topologies have as yet been experimentally realized, employing solution-based synthetic methods in most cases.2,3 Theoretical studies have predicted that further ZIF structures could be synthetically accessible.7−9 Indeed, even in a ZIF system that had been the subject of a broad synthetic high-throughput screening study,10 we have recently discovered a new ZIF polymorph.11 However, discovery of new ZIFs is still proceeding on a trial and error basis, because our understanding of the mechanisms of formation is still rather poor. High-throughput screening studies do not appear to obviate the © XXXX American Chemical Society

need for detailed studies of the crystallization mechanisms, if we want to realize theoretically predicted and potentially existing ZIFs in a more rational manner.12 Furthermore, a mechanistic understanding is helpful for controlling crystal size and shape.13 Because it is known that fragile and unstable ZIF intermediates may undergo structural changes during work up after having quenched a reaction,14 in situ studies have to be preferred over ex situ experiments whenever feasible.15 Although such in situ studies on ZIF crystallization are still very scarce, various analytical methods have already been employed: energy-dispersive X-ray diffraction (EDXRD),16 small/wide-angle X-ray scattering (SAXS/WAXS),13,14,17,18 and static/dynamic light scattering (SLS/DLS)13,19 to follow particle/crystal nucleation and growth, X-ray absorption spectroscopy (XAS)17 to follow local structural changes during crystallization, and atomic force microscopy (AFM)20,21 to follow surface growth. Recently, electrospray ionization mass spectrometry (ESI-MS)22 has provided first insights into the Received: November 10, 2015 Revised: February 25, 2016

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DOI: 10.1021/acs.cgd.5b01594 Cryst. Growth Des. XXXX, XXX, XXX−XXX

Crystal Growth & Design

Article

For simultaneous time-resolved static and dynamic light scattering (TR-SLS/DLS) measurements, a commercial LS setup from ALV (ALV Langen/Hessen, Germany) was used. The goniometer arm of the LS setup was equipped with eight APD detectors angularly separated by eight degrees from each other. The scattered intensity measured by the detectors was fed into ALV-7000 digital correlators enabling recording real time intensity autocorrelation functions simultaneously at eight scattering angles. During a kinetic run, the goniometer arm was kept fixed at a particular position such that the experimental scattering angles covered a range from 25 to 81 degrees. The measurement time was 10 s at a particular time point. Evaluation of Light Scattering Data. The TR-SLS data were evaluated following Guinier’s approximation at the small angle limit33

dynamics of multinuclear complexes during prenucleation and nucleation stages. Additionally, liquid cell transmission electron microscopy (LC-TEM)23 has been demonstrated to enable monitoring particle growth processes. We are currently studying [Zn(dcim)2] (dcim = 4,5dichloroimidazolate) as a model ZIF system with respect to polymorphism and phase formation mechanisms.11,14 In this system, one previously well-known polymorph with RHO topology ([Zn(dcim)2]-RHO, ZIF-71), that was first synthesized solvothermally,10 has gained considerable interest for applications in shock-adsorption24 and separation.25−30 Various similar room-temperature solution-based methods for the production of ZIF-71 nano- and microcrystals have been published recently.26,29−31 The methods differ in the metal salts and solvents employed. Herein, we report on combined in situ SLS/DLS and SAXS/WAXS experiments performed on our recently developed ZIF-71 synthesis,11 which results in the formation of well-defined nanocrystals on time scales ranging from seconds to minutes. Successful monitoring of this process necessitated the application of analytical methods with an appropriately high time resolution. We have obtained new insights into ZIF nucleation and growth, that complement and extend current knowledge, mostly gained by studies of the formation of prototypical [Zn(mim)2]-SOD (mim = 2-methylimidazolate, ZIF-8).

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⎛ Kc ⎞ ⎛ 1 ⎞ 1 2 2 ln⎜ ⎟ = ln⎜ ⎟ + Rg q 3 ⎝ Mw ⎠ ⎝ R(q) ⎠

where q is the scattering vector determined by the scattering angle θ and Mw and Rg2 are, respectively, the weight-average molar mass and zaverage of the squared radius of gyration. R(q) is the excess absolute scattering intensity at an angle given by q. c is the concentration of scattering species in g·mL−1. The scattering species in the present experiments are particles with a composition of Zn(dcim)2, the concentrations of which were calculated with the initial molar concentration of Zn2+ ions in the respective solutions assuming a complete stoichiometric reaction as shown in eq 1. This calculation was not applicable for the solution with a composition where the Hdcim was present in substoichiometric amount (i.e., Zn2+/Hdcim =1:1). In the latter case, c was calculated by taking into account that only half of the initial Zn2+ ions were available for forming the particles. The molar mass, Mw, obtained was further corrected for transmission loss of the scattering solution during particle growth process (see sections S1 and S2 in the Supporting Information for a detailed description of the SLS data evaluation and subsequent correction of Mw). Combined TR-SLS/DLS experiments yielded Mw and Rg based on the scattering intensities at eight different angles in the same way as described above. Additionally, from the fluctuations of scattered light intensity at a given scattering angle, apparent diffusion coefficients, Dapp, are evaluated according to cumulant analysis34 (see section S3 in Supporting Information). Extrapolating Dapp to zero scattering angle gives the z-average diffusion coefficient Dz according to

EXPERIMENTAL SECTION

Materials and General Synthetic Method. Zinc nitrate (Zn(NO3)2·6H2O; Sigma-Aldrich, >99%), 4,5-dichloroimidazole (Hdcim; Sigma-Aldrich, >98%), and 1-propanol (1-PrOH; SigmaAldrich, >99.5%) were used as the source of Zn2+, linker, and solvent, respectively. All chemicals were used as received. The ZIF-71 nanocrystal synthesis studied here closely followed the protocol reported elsewhere.11 Generally, 1-propanolic solutions of the zinc salt and linker were combined as described below for the respective analytical methods. The formation of ZIF-71 occurs according to the following gross reaction.

Zn(NO3)2 + 2C3H 2Cl 2N2 → Zn(C3HCl 2N2)2 + 2HNO3

(2)

(1)

Dapp = Dz(1 + kDq2R g2)

In Situ Time-Resolved Light Scattering (TR-LS). Solutions of Zn(NO3)2·6H2O and Hdcim were prepared by directly combining the solid chemicals with appropriate amounts of 1-PrOH. At first, 3 mL of the Zn(NO3)2·6H2O solution were filtered into a precleaned LS cuvette using a 0.2 μm syringe filter. Then, 3 mL of linker solution was filtered into the same cuvette making the overall compositions Zn2+/ Hdcim/1-PrOH = 1:X:4000 or 1:X:2000 with X = 1, 2, 3, 4, 5, 6, 8. The cuvette was gently shaken for a couple of seconds and then placed inside the goniometer of the LS instrument. The time difference between the start of mixing the solutions and the start of collecting data (dead time) varied between 20 and 30 s. All TR-LS experiments were performed at 25 °C. Two different LS setups were used for the present work both applying a He−Ne gas laser as the source of incident light (wavelength: λ = 632.8 nm) but differing in terms of detection and processing of the scattered light. For time-resolved static light scattering (TR-SLS) measurements, a custom built multiangle goniometer was used. The details of the setup can be found elsewhere.32 The scattered intensity was detected simultaneously at 19 angles covering an angular range of 26° < θ < 143°. The time required to record a single scattering curve was 2 ms. The time resolution of a given kinetic run depended on exactly how many of such single scattering curves had to be averaged in order to get an acceptable statistics. The time resolution varied between 2 s (for Zn2+/Hdcim/1-PrOH = 1:8:2000) to 4 s (for Zn2+/Hdcim/1-PrOH = 1:1:4000).

(3)

An effective average hydrodynamic radius, Rh, for the scatterers is obtained from Dz by using the Stokes−Einstein relation Rh =

kBT 1 6πη Dz

(4)

where T is the absolute temperature and η is the viscosity of the solvent. In Situ Time-Resolved Small- and Wide-Angle X-ray Scattering (TR-SAXS/WAXS). The experiments were performed at beamline ID02 at the European Synchrotron Radiation Facility (Grenoble, France) using a wavelength of 0.1 nm. SAXS and WAXS intensities were recorded on a 2D FreLoN35 (Fast Readout, Low Noise) CCD detector. The detector was set at two different distances (1.5 and 8 m) from the quartz glass capillary (1.5 mm diameter), which served as the scattering cell. The acquisition setup was synchronized with a Biologic SFM-400 stopped-flow device for rapid turbulent mixing of the 1-propanolic Zn(NO3)2·6H2O and Hdcim solutions in order to define the onset of the rapid reaction as precisely as possible.36 Two reactions having the total molar ratios Zn2+/ Hdcim/1-PrOH = 1:4:1000 and 1:4:2000, respectively, were studied. A circulating fluid bath was used to keep the temperature at 25 °C. The raw intensity data were normalized to an absolute scale after correcting for dark level and sensitivity of the detector and the scattering intensity of pure 1-PrOH. The normalized 2D data were azimuthally averaged to obtain the 1D scattering profiles. B



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Evaluation of X-ray Scattering Data. The TR-SAXS patterns were fitted using the Beaucage empirical formula37 for one structural level expressed as

I(mm−1) = I0e

3p

{erf( )} +B qR g

−q2R g2

6

qp

+ BG

(5)

where the absolute scattering cross section per unit sample volume, I(q), is expressed as sum of a Guinier decay (first term of eq 5) to account for the scattering at low q and a power law decay (second term of eq 5). In the second term, p is the Porod exponent characteristic for the respective mass or surface fractal of the scattering entities and depends on the particle topology. BG is the scattering intensity of the first solution measurement at the 1.5 m detector distance and was kept fixed during fitting. The SAXS data fitting software package SansView38 was used for data evaluation. For those scattering patterns, which are expected to depend on two species, namely, big particles and small clusters, an additional Guinier term was added to eq 5.

I(mm−1) = I0e

3p

{erf( )} +B qR g

−q2R g2

6

q

p

2 2

+ I0,ce−q R g,c + BG (6)

Figure 1. (Top) Time-dependent molar mass (Mw) and (bottom) radius of gyration (Rg) of the growing particles from TR-SLS measurements for a series of solutions with compositions Zn2+/ Hdcim/1-PrOH = 1:X:4000. The values of X are shown in the diagrams. Time t = 0 represents the instant at which the two precursor solutions were mixed.

where the subscript c denotes the clusters. A reasoning of the applicability of eq 6 for selected SAXS patterns will be given in Results and Discussion. Bragg reflections seen in the WAXS region were fitted with a pseudo-Voigt function to extract integrated intensities, which, in turn, were normalized to the maximal integrated intensity reached at the end of the reaction. Normalization yielded the extent of crystallization, β, as a function of time. For kinetic analysis, the resulting experimental data β(t) were fitted applying the Gualtieri equation,39

β(t ) =

1 1 + e−(t − a)/ b

intensity remained close to the background level before it rose due to particle formation. This lag time was largest at 1:1:4000 (∼150 s) and decreased with increasing linker concentration, i.e., when the reaction kinetics became increasingly faster (see Figure S4 in the Supporting Information). The observation is in line with our previous findings for [Zn(im)2]-zni (im = imidazolate, ZIF-zni) formation.19 The smallest radius measured varied between 30 nm < Rg < 50 nm. The values approximately correspond to the lower size limit detectable by SLS. Solutions with increasing linker concentration produced final particles with decreasing size, the Rg values of which were 100 s), a well developed power law between the scattered intensity and q according to Porod with a slope of p ≈ −1.8 can be identified, suggesting bigger structures, which would produce a Guinier shoulder at a much lower q inaccessible to the present SAXS experiment. These bigger structures can be attributed to aggregates of particles, which result from the same aggregation process that might have contributed to the upturn of the correlation plots between Rg and Mw measured by TR-SLS (Figure 3) and the aggregates observed in SEM images (Figure 4). One additional power law appearing at the high q end of Figure 5a can be attributed to surface scattering from the particles according to Porod’s law. In a first attempt, this power law along with the Guinier shoulder at q < 0.1 nm−1 was fitted by the unified Beaucage law according to eq 5. The values of the slopes, p, obtained from such fits are found to be constant at p ≈ 3.7 for all measurements at t > 100 s (Figure S8a in Supporting Information). This is very close to the value expected for scattering from smooth surfaces (p = −4). For measurements at t < 100 s, however, the fitted value of p decreased monotonically. We have assumed that at these short times, the scattering intensities at high q were not only governed by the surface scattering from the particles. Additional contribution from small clusters, which produce a Guinier shoulder at q ≈ 0.2 nm−1, interfered with the Porod slope and hence gave smaller apparent p values. Accordingly, an additional Guinier decay was added in eq 6 for fitting the data. In Figure S8b in the Supporting Information, fitting quality of both functions is compared at three selected measurement times. For a measurement at t ≈ 50 s, eq 6 certainly fits the data better than eq 5. At later times (t ≈ 80 s), E



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the scattering contribution from the clusters at q ≈ 0.2 nm−1 becomes negligible and the experimental data could be well fitted by eq 5. The formation of clusters in the initial stages could be seen more clearly with the experiment at a detector distance of 1.5 m (Figure 5b), where smaller length scales are probed. The increase of the scattering intensity within 0.1 < q < 1 nm−1 implies the formation of clusters. However, the corresponding Guinier shoulder disappeared very quickly (at t ≈ 10 s), and an upturn of the scattering intensity at q ≈ 0.1 nm−1 (Figure 5b) appeared due to the formation of the particles. The disappearance of the scattering intensity seen at q ≈ 0.2 nm−1 is caused by the consumption of clusters while they are incorporated in the particles, either by direct attachment or via prior dissolution forming smaller units. Figure 5b also shows that the clusters could be seen from the second measurement onward which corresponds to 0.6 s, whereas the 110 Bragg peak, which is by far the strongest reflection in the PXRD pattern of ZIF-71 (see Figure S7 in the Supporting Information), appeared much later in time at ∼70 s in the WAXS region at q ≈ 3.1 nm−1. Figure 6a summarizes the Rg values of the clusters and particles obtained from the X-ray scattering experiments shown in Figure 5. For times t < 15 s, Rg values were obtained using a Beaucage fit (eq 5) to curves in Figure 5a,b, which characterize clusters. For times covering 15 s < t < 80 s the empirical

Beaucage formula with an additional Guinier term according to eq 6 has been applied to curves in Figure 5a, and for t > 80 s again a simple Beaucage law based on eq 5 fit well to curves in Figure 5a. As has been further outlined in the Supporting Information (Figure S9), a fit with a model form factor for polydisperse spheres in the regime of 0.05 nm−1 to 0.5 nm−1 in Figure 5a gave Rg values for particles which are in agreement with those given by eq 6 with a typical polydispersity (weightaverage particle mass)/(number-average particle mass) of 1.4. The cluster size increased only slightly from Rg ≈ 4 nm to Rg ≈ 6 nm, whereas the particle size increased up to Rg ≈ 70 nm. The values are compared with Rg values obtained by TR-SLS with the same solution composition. Until t ≈ 70 s, the Rg values measured by both methods for the particles are close to each other. Beyond 70 s, Rg values from TR-SLS got increasingly larger than the respective values from SAXS, as at these later stages LS probes aggregates of particles, which were too large to be accessible to a SAXS based size analysis. In Figure 6b, the scattering intensities of the clusters and particles at zero q are plotted against time. The scattering intensity of the clusters increased at first and then decreased which corresponds to the hump seen in Figure 5b at q ≈ 0.2 nm−1 and further demonstrates that clusters disappear to form the particles. The extent of crystallization, β, as a function of time is shown in Figure 7 along with a fit of the experimental β

Figure 7. Extent of crystallization obtained from the 110 Bragg reflection appearing in the WAXS region (Figure 5b) at q ≈ 3.1 nm−1. The red line was obtained by fitting the data points with the Gualtieri formula.

values applying the Gualtieri equation (eq 7). From the Gualtieri fit (via extrapolation of the β values to zero) an induction time of ∼35 s can be inferred before first appearance of crystalline domains with the periodic ZIF-71 structure. At about that time, which is much later than the first appearance of clusters (at t ≈ 0.6 s) and particles (at t ≈ 15 s), the clusters start to disappear and the particles have grown to approximately three-quarters of their final size. This strongly suggests that both the clusters and early particles were amorphous. The Gualtieri analysis revealed that the rate constant of crystallite nucleation (kn = 0.024(5) s−1) is about two times larger than the rate constant of crystallite growth (kg = 0.0117(4) s−1). This observation might be explained with a heterogeneous formation of crystalline domains in the amorphous particles (possibly near to the particle-solution interface) and a subsequent slow reorganization of the amorphous parts into the periodic ZIF-71 structure.

Figure 6. Radii of gyration (a) and scattering intensities at q = 0 (b) as obtained from TR-SAXS (○, ●, △) and TR-SLS (red solid circles) for the particle growth from a solution with composition Zn2+/Hdcim/1PrOH = 1:4:2000. The symbols denote: Fit with eq 5 to the data in Figure 5b indicating clusters (△); fit of eq 5 to data at t < 15 s in Figure 5a indicating clusters or particles (○); fit of eq 6 to data in Figure 5(a) indicating clusters and particles (●); fit of eq 5 to data at t > 80 s in Figure 5a indicating particles (○). The dashed vertical line indicates the first appearance of the 110 Bragg peak in Figure 5b. F



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clusters and particles. For the clusters an exponent close to 1/3 was determined. This indicates that the clusters grew via coagulation; i.e., any entity (clusters and smaller units) can react with any other entity.41,42 For the particles, on the other hand, the magnitude of α approached a limiting value very close to 1/6, which agrees with the value obtained with TR-SLS, and suggests particle growth by a monomer-addition mechanism.41,42 TR-SAXS/WAXS experiments on a more concentrated solution, which corresponds to the original protocol of our ZIF-71 nanocrystal synthesis (Zn 2+ /Hcdim/1-PrOH = 1:4:1000), revealed the same sequence of stages with intermediate amorphous clusters and particles as well as the same monomer-addition growth of particles. However, the reaction was even faster (see Figure S10 and Figure S11 in the Supporting Information). The 110 Bragg reflection of ZIF-71 appeared already at ∼18 s. Hence, the lifetime of amorphous intermediates may become very short, and detection of such species became difficult, a situation already encountered during ZIF-8 formation under similar conditions.17

This hypothesis is supported by the fact, that particle growth as determined by SAXS (Figure 6) was apparently not affected by the crystallization process. Moreover, the hypothesis appears reasonable in light of recent demonstrations of ready occurrence of solvent-assisted linker exchange reactions in ZIF/solution systems (ZIF-71, ZIF-8).43,44 Such amorphousto-crystalline particle reorganizations have also been experimentally observed in other chemical systems (e.g., zeolites, CaCO3).45,46 For the clusters and particles, respectively, a power law relation between Rg and scattering intensity, I(q = 0), extrapolated to zero q could be established from the TRSAXS data, applying eq 8 and replacing Mw by I(q = 0). As can be seen in Figure 8, the exponents α are distinctly different for

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CONCLUSION On the basis of results from in situ TR-SLS/DLS and TRSAXS/WAXS experiments we propose a mechanism for the fast formation of ZIF-71 nanocrystals in comparatively dilute alcoholic solutions that is outlined schematically in Figure 9. From the dissolved metal salt and linker, a population of small amorphous clusters forms which grow via a coagulation process. The clusters, in turn, are consumed in the course of the subsequent formation and growth of a second population of bigger amorphous particles. These particles grow via a monomer-addition mechanism with the monomers being significantly smaller in size, but as yet of unknown nature. Possible monomeric entities are the clusters, multinuclear complexes (oligomers)22 and/or metal ions and linker

Figure 8. Correlation between the radius of gyration and scattered intensity extrapolated to q = 0 established from TR-SAXS experiments for a solution with a composition of Zn2+/Hdcim/1-PrOH = 1:4:2000. The data are introduced in Figure 6 and the symbols have the same meaning as in Figure 6. The α values used to draw the lines are 1/3 (red) and 1/6 (green), respectively.

Figure 9. A simplistic scheme outlining the proposed steps and intermediates in the formation of ZIF-71 in 1-propanolic solution containing Zn(NO3)2·6H2O as the metal salt and Hdcim as the linker. The times given correspond to the in situ experiments with the composition Zn2+/ Hdcim/1-PrOH = 1:4:2000. G



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molecules.20 The attaching entities may change with time, as concentration of nutrients in solution decreases. Crystallization occurs after an induction time probably heterogeneously in the amorphous particles with subsequent particle transformation into the periodic ZIF-71 structure. The reactions accelerate with increasing linker-to-metal ratio, yielding nanocrystals of decreasing final size. Thereby, the lifetimes of amorphous intermediates may become very short and hence hardly observable experimentally. At later stages, the nanocrystals tend to randomly aggregate. This mechanism resembles the crystallization mechanism of ZIF-8 under similar conditions,13,17,23 suggesting a more generally valid scheme for ZIF formation, independent of topology. A recent in situ ESI-MS study on ZIF-8 by Lim et al.22 has demonstrated formation and depletion of multinuclear complexes during prenucleation and nucleation stages. It is reasonable to assume that similar oligomeric species form via complex formation, complex deprotonation and ligand exchange reactions13 in the case of ZIF-71 formation. On the other hand, the mechanism differs partly from that observed previously by us for the formation of dense ZIF-zni in similarly dilute solutions, where amorphous particles form rapidly over the first few hundreds of seconds and light scattering only revealed an increase of the number density of particles throughout this period. Later, possibly with the onset of crystallization, those particles start to aggregate via a monomer-addition mechanism with the particles now acting as monomer. 14,19 The differences among the particle aggregation processes may be related to the fact that ZIF-zni has an anisotropic (polar) crystal structure promoting oriented attachment, whereas ZIF-71 and ZIF-8 are cubic phases favoring random aggregation. Formation of amorphous nanoparticles,48,49 where the particles grow via monomer addition over a period of time,41,42,47 which in most cases is significantly longer than a preceding nucleation step,41,42,47 is a frequently occurring phenomenon in crystallization from supersaturated solution. Aside from ZIF-8 and ZIF-71 it has also been observed with CaCO3, and silica synthesized at different reaction conditions. Among those systems, silica particles establish a special case inasmuch as the amorphous phase does not crystallize but remains kinetically trapped in a glassy state. Our work has demonstrated that advanced in situ scattering techniques with high resolution in time can be combined to gain significant insight into fast ZIF crystallization processes. Such mechanistic insight is important for further developing ZIF synthesis toward a more rational control of crystal phase/ polymorph as well as crystal size/shape. Obtaining quantitative information on the kinetic parameters of ZIF-71 particle growth using mathematical modeling will be attempted in a future work.

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AUTHOR INFORMATION

Corresponding Authors

*(M.W.) E-mail: [email protected]. *(K.H.) E-mail: [email protected]. Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS This work was supported by grants from the DFG Priority Program SPP1415 “Crystalline Non-Equilibrium Phases” (WI1156/3-2, HU 807/14-2). Provision of beam time at beamline ID02 by the ESRF is gratefully acknowledged. We thank Dr. C. A. Schröder for his assistance during SAXS/WAXS experiments at ID02, and Dr. T. Narayanan for helpful scientific discussions.

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REFERENCES

(1) Furukawa, H.; Cordova, K. E.; O’Keeffe, M.; Yaghi, O. M. Science 2013, 341, 1230444. (2) Phan, A.; Doonan, C. J.; Uribe-Romo, F. J.; Knobler, C. B.; O’Keeffe, M.; Yaghi, O. M. Acc. Chem. Res. 2010, 43, 58. (3) Zhang, J. P.; Zhang, Y. B.; Lin, J. B.; Chen, X. M. Chem. Rev. 2012, 112, 1001. (4) Biswal, B. P.; Panda, T.; Banerjee, R. Chem. Commun. 2012, 48, 11868. (5) Nguyen, N. T. T.; Furukawa, H.; Gándara, F.; Nguyen, H. T.; Cordova, K. E.; Yaghi, O. M. Angew. Chem., Int. Ed. 2014, 53, 10645. (6) Burtch, N. C.; Jasuja, H.; Walton, K. S. Chem. Rev. 2014, 114, 10575. (7) Baburin, I. A.; Leoni, S.; Seifert, G. J. Phys. Chem. B 2008, 112, 9437. (8) Gee, J. A.; Sholl, D. S. J. Phys. Chem. C 2013, 117, 20636. (9) Bouëssel du Bourg, L. B.; Ortiz, A. U.; Boutin, A.; Courdert, F.-X. APL Mater. 2014, 2, 124110. (10) Banerjee, R.; Phan, A.; Wang, B.; Knobler, C.; Furukawa, H.; O’Keeffe, M.; Yaghi, O. M. Science 2008, 319, 939. (11) Schweinefuß, M. E.; Springer, S.; Baburin, I. A.; Hikov, T.; Huber, K.; Leoni, S.; Wiebcke, M. Dalton Trans. 2014, 43, 3528. (12) Stock, N.; Biswas, S. Chem. Rev. 2012, 112, 933. (13) Cravillon, J.; Nayuk, R.; Springer, S.; Feldhoff, A.; Huber, K.; Wiebcke, M. Chem. Mater. 2011, 23, 2130. (14) Schröder, C. A.; Saha, S.; Huber, K.; Leoni, S.; Wiebcke, M. Z. Kristallogr. - Cryst. Mater. 2014, 229, 807. (15) Pienack, N.; Bensch, W. Angew. Chem., Int. Ed. 2011, 50, 2014. (16) Cravillon, J.; Schröder, C. A.; Bux, H.; Rothkirch, A.; Caro, J.; Wiebcke, M. CrystEngComm 2012, 14, 492. (17) Cravillon, J.; Schröder, C. A.; Nayuk, R.; Gummel, J.; Huber, K.; Wiebcke, M. Angew. Chem., Int. Ed. 2011, 50, 8067. (18) Goesten, M.; Stavitski, E.; Pidko, E. A.; Gücüyener, C.; Boshuizen, B.; Ehrlich, S. N.; Hensen, E. J. M.; Kapteijn, F.; Gascon, J. Chem. - Eur. J. 2013, 19, 7809. (19) Hikov, T.; Schröder, C. A.; Cravillon, J.; Wiebcke, M.; Huber, K. Phys. Chem. Chem. Phys. 2012, 14, 511. (20) Moh, P. Y.; Cubillas, P.; Anderson, M. W.; Attfield, M. P. J. Am. Chem. Soc. 2011, 133, 13304. (21) Cubillas, P.; Anderson, M. W.; Attfield, M. P. Chem. - Eur. J. 2013, 19, 8236. (22) Lim, I. H.; Schrader, W.; Schüth, F. Chem. Mater. 2015, 27, 3088. (23) Patterson, J. P.; Abellan, P.; Denny, M. S., Jr.; Park, C.; Browning, N. D.; Cohen, S. M.; Evans, J. E.; Gianneschi, N. C. J. Am. Chem. Soc. 2015, 137, 7322. (24) Ortiz, G.; Nouali, H.; Marichal, C.; Chaplais, G.; Patarin, J. J. Phys. Chem. C 2014, 118, 21316. (25) Zhang, K.; Lively, R. P.; Dose, M. E.; Brown, A. J.; Zhang, C.; Chung, J.; Nair, S.; Koros, W. J.; Chance, R. R. Chem. Commun. 2013, 49, 3245.

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.cgd.5b01594. SLS/DLS data evaluation, time-resolved light transmission data, impact of linker concentration on lag time, SEM images, form factor of ZIF-71 nanoparticle from TR-SLS, form factor fitting of SAXS data at 1:4:2000, SAXS/WAXS patterns at 1:4:1000 (PDF) H



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(26) Dong, X.; Lin, Y. S. Chem. Commun. 2013, 49, 1196. (27) Liu, S.; Liu, G.; Zhao, X.; Jin, W. J. Membr. Sci. 2013, 446, 181. (28) Japip, S.; Wang, H.; Xiao, Y.; Chung, T. S. J. Membr. Sci. 2014, 467, 162. (29) Wee, L. H.; Li, Y.; Zhang, K.; Davit, P.; Bordiga, S.; Jiang, J.; Vankelecom, I. F. J.; Martens, J. A. Adv. Funct. Mater. 2015, 25, 498. (30) Lively, R. P.; Dose, M. E.; Thompson, J. A.; McCool, B. A.; Chance, R. R.; Koros, W. J. Chem. Commun. 2011, 47, 8667. (31) Tu, M.; Wiktor, C.; Rösler, C.; Fischer, R. A. Chem. Commun. 2014, 50, 13258. (32) Becker, A.; Schmidt, M. Makromol. Chem., Macromol. Symp. 1991, 50, 249. (33) Guinier, A.; Fournet, J. Small-Angle Scattering of X-rays. In Structure of Matter Series; John Wiley & Sons: New York, 1955. (34) Koppel, D. E. J. Chem. Phys. 1972, 57, 4814. (35) Narayanan, T. Small Angle Scattering. In Structure from Diffraction Methods, Eds. Bruce, D. W.; O’Hare, D.; Walton, R. I., John Wiley & Sons, UK, 2014; pp 259−324. (36) Panine, P.; Finet, S.; Weiss, T. M.; Narayanan, T. Adv. Colloid Interface Sci. 2006, 127, 9. (37) Beaucage, G. J. Appl. Crystallogr. 1995, 28, 717. (38) http://www.sasview.org. (39) Gualtieri, A. F. Phys. Chem. Miner. 2001, 28, 719. (40) Burchard, W. Adv. Polym. Sci. 1983, 48, 1. (41) Liu, J.; Rieger, J.; Huber, K. Langmuir 2008, 24, 8262. (42) Liu, J.; Pancera, S.; Boyko, V.; Shukla, A.; Narayanan, T.; Huber, K. Langmuir 2010, 26, 17405. (43) Fei, H.; Cahill, J. F.; Prather, K. A.; Cohen, S. M. Inorg. Chem. 2013, 52, 4011. (44) Morabito, J. V.; Chou, L. Y.; Li, Z.; Manna, C. M.; Petroff, C. A.; Kyada, R. J.; Palomba, J. M.; Byers, J. A.; Tsung, C. K. J. Am. Chem. Soc. 2014, 136, 12540. (45) Mintova, S.; Olson, N. H.; Valtchev, V.; Bein, T. Science 1999, 283, 958. (46) Nielsen, M. H.; Aloni, S.; De Yoreo, J. J. Science 2014, 345, 1158. (47) Kley, M.; Kempter, A.; Boyko, V.; Huber, K. Langmuir 2014, 30, 12664. (48) Pontoni, D.; Bolze, J.; Dingenouts, N.; Narayanan, T.; Ballauff, M. J. Phys. Chem. B 2003, 107, 5123. (49) Pontoni, D.; Narayanan, T.; Rennie, A. R. Langmuir 2002, 18, 56.

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