Guest-controlled polymorphism and exceptionally marked bi-stability in a spin crossover 3D porous amino-functionalized coordination polymer

Functionalization of spin crossover (SCO) porous coordination polymers (PCPs) with hydrogen-bonding active groups is an efficient strategy for the research of multifunctional materials. Indeed, the interaction of guests with the...


Physical Measurements.
Magnetic Measurements.Variable temperature magnetic susceptibility data were recorded in sweep mode at a rate of 2 K/min with a Quantum Design MPMS2 SQUID magnetometer equipped with a 7 T magnet, operating at 1 T and at temperatures 50-400 K. Experimental susceptibilities were corrected for diamagnetism of the constituent atoms using Pascal's constants.
Single Crystal X-ray Diffraction.Single-crystal X-ray data were collected on an Oxford Diffraction Supernova diffractometer using graphite monochromated MoKα radiation (λ = 0.71073 Å).A multiscan absorption correction was performed.The structures were solved by direct methods using SHELXS-2014 and refined by fullmatrix least-squares on F 2 using SHELXL-2014. [3]Nonhydrogen atoms were refined anisotropically and hydrogen atoms were placed in calculated positions refined using idealized geometries (riding model) and assigned fixed isotropic displacement parameters.All details can be found in CCDCs 2277962 (1•NO2Bz_120 K), 2277963 and 2277967 (1•H2O•MeOH_260 K), which contain the supplementary crystallographic data for this article.These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
Powder X-ray diffraction measurements were performed on a PANalytical Empyrean X-ray powder diffractometer (monochromatic CuKα radiation) in capillary measurement mode.
In situ powder X-ray diffraction (PXRD).Temperature dependent measurement were performed in a Malvern PANalytical Empyrean diffractometer equipped with a TTK-600 nonambient chamber TGA experiments were carried out with a TA instruments TGA550 device equipped with a Pt/Rh oven (Tmax = 1000°C).
Table S5.List of C•••C short contacts found between the interpenetrated apical dpyan ligands in compound 1•EtOH.S6) operating between the ethanol molecules and the amino groups of the host framework.

Table S6. List of O•••N and O•••O H-bonds found between the ethanol molecules and the amine groups of the host network in
. TGA of compounds 1•xNO2Bz with different nitrobenzene contents 5 -Figure S4.TGA of a desorbed sample of 1•MeOH that was exposed to air for three days 6 -Tables S1-S4.SCXRD data 6-8 -Figure S5.Electronic density in the pores of 1•NO2Bz and 1H2O•MeOH 8 -Figure S6.Fragment of the structure of 1•EtOH showing π•••π contacts 9 -Table S5.List of C•••C short contacts in 1•EtOH 9 -Figure S7.Structure of compound 1•EtOH showing the multiple H-bond interactions 10 -Table S6.List of O•••N and O•••O H-bonds found in 1•EtOH.10 -Figure S8.TGA performed for a sample of 1•NO2Bz after being thermally treated in PXRD 11 -Figure S9.PXRD patterns of samples of 1•ø redispersed in different solvents 11 -Figure S10.Evolution with time of the thermal dependence of χMT for 1Time evolution of χMT vs T of a sample of 1. χMT vs T at different temperature scan rates for a sample of 1•0.72NO2Bz.13 -Figure S13.TGA of 1•NO2Bz after being heated inside the SQUID chamber 13 -Figure S14.χMT vs T of 1•ø before and after adsorbing water 14 -Figure S15.χMT vs T for 1•ø (empty) and for of 1•ø redispersed in different solvents 14 Electronic Supplementary Material (ESI) for Journal of Materials Chemistry C.This journal is © The Royal Society of Chemistry 2023

(
Anton Paar) with Kapton windows connected to a two-stage rotary vane vacuum pump.Diffractograms were collected in reflection geometry with a step size of 0.0131° and a counting time of 75 seconds.A PIXcel3D solid-state detector in scanning mode and a Cu anode (Cu Kα1 = 1.5406Å; Cu Kα2 = 1.5444Å) operating at 45 kV and 40 mA were employed together with 0.02° Soller slits of and ¼ divergence and anti-scatter slits.Powder samples were carefully grinded and loaded into a sample holder inside the TTK-600 non-ambient chamber and heated under dynamic vacuum (∼10 - 3 mbar).Elemental analyses (C, H, and N) were performed with a CE Instruments EA 1110 CHNS Elemental analyzer.

Figure S2 .
Figure S2.TGA-mass measurements of a sample of 1•H2O•MeOH just after removing from the mother liquor (left) and three weeks after exposed to air (right).

Figure S3 .
Figure S3.TGA of compounds 1•xNO2Bz with different nitrobenzene contents obtained from controlled heating of the original 1•NO2Bz (with 0.99 molecules of nitrobenzene)

Figure S5 .
Figure S5.Perspective views of the structures of 1•NO2Bz and 1•H2O•MeOHshowing the electronic density found in the pores and ascribed to the respective included guest.Note that whereas the nitrobenzene electronic residue is spread within the whole available void space of the pore, it is limited to specific positions for the water/methanol guests.

Figure S6 .
Figure S6.Fragment of the structure of 1•EtOH highlighting the short contacts between aromatic rings of the dpyan ligands belonging to each interpenetrated network (see tableS5).

Figure S7 .
Figure S7.Fragment of the structure of compound 1•EtOH showing the multiple H-bond interactions (see TableS6) operating between the ethanol molecules and the amino groups of the host framework.

Figure S8 .
Figure S8.TGA performed for a sample of 1•NO2Bz after being heated under successive thermal cycles from 350 to 380 K inside the powder X-ray diffractometer chamber.

Figure S10 .
Figure S10.Thermal dependence of χMT for 1•H2O•MeOH after the sample is removed from the mother liquor and exposed to air for 1 day (blue plot) and 1 week (red plot).

Figure S11 .
Figure S11.Thermal dependence of χMT of a sample of 1•0.77NO2Bz just after being obtained (in red) and one month after leaving it under ambient conditions (in black).

Figure S12 .
Figure S12.Thermal dependence of χMT at different temperature scan rates for a sample of 1•0.72NO2Bz.

Figure S13 .
Figure S13.TGA performed for a sample of 1•NO2Bz after being heated under successive thermal cycles from 350 to 380 K inside the SQUID chamber.

Figure S14 .
Figure S14.Thermal dependence of χMT for a sample of 1•ø before (red plot) and after (black plot)re-adsorbing 0.7 molecules of water under ambient conditions for three days.

Figure S15 .
Figure S15.Thermal dependence of the χMT for 1•ø (empty) and for a sample of 1•ø redispersed in a) methanol, b) ethanol and c) nitrobenzene, measured in situ throughout several χMT vs T cycles until curve stabilization (the stabilized or "saturated" curves are depicted in black).Blue plots correspond to intermediate χMT vs T cycles before stabilization.Figure d) include the saturated curves for all guests for comparison.