Accommodative Behavior of Non-porous Molecular crystal at Solid-Gas and Solid-Liquid Interface

Molecular crystals demonstrate drastically different behavior in solid and liquid state, mainly due to their difference in structural frameworks. Therefore, designing of unique structured molecular compound which can work at both these interfaces has been a challenge. Here, we present remarkable ‘molecular’ property by non-porous molecular solid crystal, dinuclear copper complex (C6H5CH(X)NH2)2CuCl2, to reversibly ‘adsorb’ HCl gas at solid-gas interface as well as ‘accommodate’ azide anion at solid-liquid interface with crystal to crystal transformation. The latter process is driven by molecular recognition, self-assembly, and anchimeric assistance. The observed transformations are feasible due to breathing of inner and outer coordination sphere around metal center resulting in change in metal polyhedra for ‘accommodating’ guest molecule. These transformations cause changes in optical, magnetic, and/or ferroelectric property offering diversity in ‘sensing’ application. With the proposed underlying principles in these exceptional reversible and cyclic transformations, we prepared a series of compounds, can facilitate designing of novel multifunctional molecular materials.

2.4 Transformation of C R /C S from B R /B S (Scheme S4) S10 2.5 Transformation of B R /B S from C R /C S (Scheme S5) S11 3 Crystal to Crystal transformation Solid-Gas interface S12 3.1 X-ray crystal structure of A 1 and B 1 ( Figure S1) S12 3.2 X-ray crystallography data of B 1 (Table S1) S13 3.3 Inner coordination and outer coordination sphere (Table S2) S14 3.4 Comparison of observed XRPD pattern of bulk sample and simulated XRPD pattern (from single crystal data) S15 3.4.1 Observed and Simulated Powder X-Ray Diffraction Patterns of B 1 ( Figure S2) S15 3.4.2 Observed (KOH treatment-A 1r ) and Simulated Powder X-Ray Diffraction Patterns of A 1 ( Figure S3) S15 3.5 Planes {h k l} passing through different 2θ values in A 1 (Table S3) S16

General Experimental Section
All chemicals and solvents were of analytical grade reagents. Unless stated otherwise, all reagents were purchased from Aldrich Chemicals and used without further purification.
Elemental analyses were determined using a Perkin Elmer Series II 2400 elemental analyzer. The IR spectra were recorded in the 4000-400 cm-1 region using KBr pellets and a Perkin Elmer Thermogravimetric analyses (TG-DTA) were performed single crystals samples using SII TG/DTA 6300 EXSTAR Analyser under N 2 atmosphere with a heating rate of 10ºC/min. For reaction monitoring (A 1 to B 1 and A S to B S ), Powder X-ray diffraction were collected in the 2θ range 5-50º at 300K for polycrystalline samples on Philips X'pert MPD System. All of the bulk polycrystalline samples were ground in an agate mortar and pestle and filled into 0.5 mm glass capillaries and recorded on 'Xcalibur, Eos, Gemini' Diffractometer in the 2θ range 5-50º at 300K.
Specific optical rotation (SOR) activity was recorded on Jasco P-2000 Polarimeter with sodium source.

X-ray Crystallography
Single-crystal data of B R and B S were collected on a Bruker Smart 1000 CCD Diffractometer, with Mo KR radiation (ì ) 0.710 73 Å). All empirical absorption corrections were applied by using the SADABS program-14. The structures were solved using direct methods, which yielded the positions of all non-H atoms. These were refined first isotropically and then anisotropically.
All of the H atoms of the ligands were placed in calculated positions with fixed isotropic thermal parameters and included in the structure factor calculations in the final stage of full-matrix leastsquares refinement. All calculations were performed using the SHELXTL system of computer programs.15.

Scheme S2:
The dry HCl gas was passed in a sample vial containing A 1 /A R /A S (1 g). The reaction takes place in 2-3 hrs with observable color change to obtain B 1 /B R /B S respectively. Yield:-100%

Transformation of C R /C S from A R /A S (Single crystal to single crystal transformation)
Scheme S3: ; (c) A 1 with space filled style denotes the absence of porosity.  (Note the peak due to eliminated KCl at 2θ=28º) S16    (3) 7.253 (2) 13.926 (4) 10.582 (3) 7.257 (2) 13.940 (3) (15) Cu ( Grinding B S with KOH led to a color change from yellow green into bluish green in minutes. No change in sign of cotton effect during conversion of B S to A S (r).

Specific Optical Rotation (SOR) activity on A R and A S , B R and B S
TableS6: SOR data on A R and A S , B R and B S in methanol at 30ºC.

Sr. No.
Angle of minimum deviation (°) Average (°)  Hysteresis measurements gave a well-defined loop for B R with the maximum field of 0.865kVcm -1 . The coercive field Ec observed at 0.865 kVcm -1 while remnant polarization Pr observed at 155.10 µCcm -2 at 300 K.

Crystal to Crystal transformation at Solid-Liquid interface: Self assembly, Molecular Recognition and Anchimeric assistance
5.1 X-ray crystal structure of C R , C S and its crystal packing