Conformation–aggregation interplay in the simplest aliphatic ethers probed under high pressure

The most stable trans–trans conformation of the diethyl ether molecule hinders its aggregation due to restricted access to the oxygen atom. This hindrance can be removed by conformational transformation under high pressure.


Figure S1 .
Figure S1.Stages of the dimethyl ether (DME) phase β single-crystal growth inside the DAC chamber: (a) polycrystalline mass grown isothermally at 295 K; (b) one crystal seed at 325 K; (c-i) the single crystal cooled to 311 K and (j) filling the whole volume of the DAC chamber at 295 K and 3.30 GPa.The ruby chips, for pressure calibration, lie in the central part of the DAC.

Figure S2 .
Figure S2.Stages of the DME phase β single-crystal growth inside the DAC chamber: (a) polycrystalline mass grown isothermally at 295 K; (b) polycrystal-liquid equilibrium at 351 K; (c) one crystal seed at 353 K; (d-i) the single crystal cooled to 347 K and (j) filling the DAC chamber at 295 K and 3.90 GPa.The ruby chip, for pressure calibration, is located in the central part of the DAC.

Figure S3 .
Figure S3.Stages of the DME phase β single-crystal growth inside the DAC chamber: (a) polycrystalline mass grown isothermally at 295 K; (b) polycrystal-liquid equilibrium at 360 K; (c) one crystal seed at 361 K; (d-i) the single crystal cooled to 346 K and (j) filling the whole volume of the DAC chamber at 295 K and 4.30 GPa.The ruby chip, for pressure calibration, is placed in the central part of the DAC.

Figure S4 .
Figure S4.Stages of the DME phase γ single-crystal growth inside the DAC chamber: (a) polycrystal mass grown isothermally at 295 K; (b) one crystal seed at 361 K; (c-i) the single crystal cooled to 351 K and (j) filling the DAC chamber at 295 K and 4.50 GPa.The ruby chips, for pressure calibration, lie in the upper part of the DAC.

Figure S5 .
Figure S5.Stages of the DME phase γ single-crystal growth inside the DAC chamber: (a) polycrystalline mass grown isothermally at 295 K; (b) polycrystal-liquid equilibrium at 372 K; (c) one crystal seed at 374 K; (d-i) the single crystal cooled to 369 K and (j) filling the whole volume DAC chamber at 295 K and 5.60 GPa.The ruby chips, for pressure calibration, are placed in the central and left part of the DAC.

Figure S6 .
Figure S6.Stages of the DME phase γ single-crystal growth inside the DAC chamber: (a) polycrystalline mass grown isothermally at 295 K; (b) polycrystal-liquid equilibrium at 396 K; (c) one crystal seed at 399 K; (d-i) the single crystal cooled to 394 K and (j) filling the whole volume DAC chamber at 295 K and 7.30 GPa.The ruby chips, for pressure calibration, lie in the central and left part of the DAC.

Figure S7 .
Figure S7.Stages of the diethyl ether (DEE) phase β single-crystal growth inside the DAC chamber: (a) polycrystalline mass grown isothermally at 295 K; (b) polycrystal-liquid equilibrium at 344 K; (c) one crystal seed at 345 K; (d-i) the single crystal cooled to 317 K and (j) filling the whole volume of DAC chamber at 295 K and 1.85 GPa.The ruby chip, for pressure calibration, is placed in the central part of the DAC chamber.

Figure S8 .
Figure S8.Stages of the DEE phase β single-crystal growth inside the DAC chamber: (a) singlecrystal-liquid equilibrium at 308 K; (b) single-crystal-liquid equilibrium at 348 K; (c) one crystal seed at 352 K;(d-i) the single crystal cooled to 331 K and (j) filling the DAC chamber at 295 K and 2.15 GPa.The ruby chip, for pressure calibration, lie in the central part (a-f) and then it is moved to the upper part (g-j) of the DAC.

Figure S9 .
Figure S9.Stages of the DEE phase β single-crystal growth inside the DAC chamber: (a) singlecrystal-liquid equilibrium at 360 K; (b) single-crystal-liquid equilibrium at 361 K; (c) one crystal seed at 362 K; (d-i) the single crystal cooled to 338 K and (j) filling the whole volume of DAC chamber at 295 K and 2.45 GPa.The ruby chip for pressure calibration is located in the upper part of the DAC.

Figure S10 .
Figure S10.Stages of the DEE phase β single-crystal growth inside the DAC chamber: (a) one crystal seed at 368 K; (b-i) the single crystal cooled to 345 K and (j) filling the DAC chamber at 295 K and 2.65 GPa.The ruby chip, for pressure calibration, lies in the upper part of the DAC.

Figure S11 .
Figure S11.Stages of the DEE phase γ single-crystal growth inside the DAC chamber: (a) polycrystal-liquid equilibrium at 361 K; (b) polycrystal-liquid equilibrium at 363 K; (c) one crystal seed at 359 K; (d-i) the single crystal cooled to 331 K and (j) filling the whole volume of DAC chamber at 295 K and 2.65 GPa.The ruby chip, for pressure calibration, lies in the upper part of the DAC.

Figure S12 .
Figure S12.Stages of the DEE phase δ single-crystal growth inside the DAC chamber: (a) polycrystalline mass grown isothermally at 295 K; (b) three single-crystals-liquid equilibrium at 405 K; (c) one crystal seed at 391 K; (d-i) the single crystal cooled to 341 K and (j) filling the DAC chamber at 295 K and 2.80 GPa.The ruby chip, for pressure calibration, lies in the bottom part of the DAC.

Figure S13 .
Figure S13.Stages of the DEE phase δ single-crystal growth inside the DAC chamber: (a) polycrystal-liquid equilibrium at 443 K; (b) polycrystal-liquid equilibrium at 444 K; (c) one crystal seed at 445 K; (d-i) the single crystal cooled to 387 K and (j) filling the whole volume of DAC chamber at 295 K and 3.45 GPa.The ruby chip, for pressure calibration, lies in the central part of the DAC.

Figure S14 .
Figure S14.Stages of the dipropyl ether (DPE) phase α single-crystal growth inside the DAC chamber: (a) polycrystal-liquid equilibrium at 334 K; (b) one crystal seed at 334 K; (c-i) the single crystal cooled to 306 K and (j) filling the DAC chamber at 295 K and 1.70 GPa.The ruby chip, for pressure calibration, lies in the central part of the DAC.

Figure S15 .
Figure S15.Stages of the DPE phase α single-crystal growth inside the DAC chamber: (a) one crystal seed at 356 K; (b-i) the single crystal cooled to 318 K and (j) filling the whole volume of DAC chamber at 295 K and 2.10 GPa.The ruby chip, for pressure calibration, lies in the central part of the DAC.

Figure S16 .
Figure S16.Stages of the DPE phase α single-crystal growth inside the DAC chamber: (a) polycrystal-liquid equilibrium at 393 K; (b) one crystal seed at 396 K; (c-i) the single crystal cooled to 356 K and (j) filling the DAC chamber at 295 K and 2.80 GPa.The ruby chip for pressure calibration lies in the central part of the DAC.

Figure S17 .
Figure S17.Stages of the DPE phase α single-crystal growth inside the DAC chamber: (a) polycrystal-liquid equilibrium at 295 (b) polycrystal-liquid equilibrium at 437 K; (c) one crystal seed at 433 K; (d-i) the single crystal cooled to 401 K and (j) filling the whole volume of DAC chamber at 295 K and 3.85 GPa.The ruby chip, for pressure calibration, lies in the central part of the DAC.

Figure S18 .
Figure S18.Stages of the DPE phase α single-crystal growth inside the DAC chamber: (a) polycrystal-liquid equilibrium at 295 K; (b) one crystal seed at 483 K; (c-i) the single crystal cooled to 424 K and (j) filling the DAC chamber at 295 K and 5.30 GPa.The ruby chip, for pressure calibration, lies in the central part of the DAC.

Figure S19 .
Figure S19.Intermolecular distances plotted as a function of pressure in DME.Four shortest distances for two types of interactions are presented: full shapes represent H•••H whereas empty shapes depict the H•••O distances.The black horizontal lines show the sum of the van der Waals radii of H and O of 2.72 Å, of H and H of 2.4 Å.The estimated standard deviations are smaller than the plotted symbols.

Figure S20 .
Figure S20.Intermolecular distances plotted as a function of pressure in DEE.Four shortest distances for two types of interactions are presented: full shapes represent H•••H whereas empty shapes depict the H•••O distances (only two shortest H•••O distances for DEE γ are indicated).The black horizontal lines show the sum of the van der Waals radii of H and O of 2.72 Å, and of H and H of 2.4 Å.The estimated standard deviations are smaller than the plotted symbols.

Figure S21 .
Figure S21.Intermolecular distances plotted as a function of pressure in DPE.Four shortest distances for two types of interactions are presented: full shapes represent H•••H whereas empty shapes depict the H•••O distances.The black horizontal lines show the sum of the van der Waals radii of H and O of 2.72 Å, and of H and H of 2.4 Å.The estimated standard deviations are smaller than the plotted symbols.

Figure S24 .
Figure S24.The number of H-donors accepting the O-atoms within the hydrogen bonds CH⋅••O (per one molecule in the unit cell) in different phases of DME, DEE and DPE.

Figure S25 .
Figure S25.CH•••O hydrogen bonding patterns in the crystal structures of DME polymorphs (a) β and (b) γ.The symmetry independent molecules are indicated in green, whereas the CH•••O contacts are marked by dotted lines.

Figure S26 .
Figure S26.CH•••O hydrogen bonding patterns in the high-pressure crystal structure of DPE.The symmetry independent molecule is indicated in green, whereas the CH•••O contacts are marked by dotted lines.

Table S2 .
Crystal data and structure refinement details of DEE phase β at 1.85, 2.15, 2.45, 2.65 GPa and phase γ at 2.65 GPa (all at 295 K).