Deuteration-Enhanced Negative Thermal Expansion and Negative Area Compressibility in a Three-Dimensional Hydrogen Bonded Network

Abstract

Negative area compressibility (NAC) and negative thermal expansion (NTE) are material behaviors raising high hope for applications such as ultrasensitive manometry and thermometry. However, the group of NAC materials is primarily limited to two-dimensional (2D) coordination compounds whose layered structure is prone to bidirectional compression when pressurized. Here, we report an alternative strategy that does not employ the formation of metal−organic systems but takes advantage of the pliability of hydrogen-bonded networks for searching materials with very rare NLC and NAC behaviors. Indeed, a strong NAC property, coupled with large NTE, has been identified for the hydrogen-bonded hydrochloride salt of Larginine homologue (S)-2-amino-3-guanidinopropanoic acid monochloride − (HAmGP)Cl and its deuterated analogue − (DAmGP)Cl. While both structures feature isostructural phase transition at ca. 0.88 GPa, it is discovered that the replacement of protium with deuterium significantly boosts NAC magnitudes: phase II of (DAmGP)Cl features over two-fold higher negative area compressibility coefficient than that of the nondeuterated analogue (β 2,3 = −17.6(27) TPa −1 for (DAmGP)Cl vs −7.9(38) TPa −1 for HAmGP)Cl. Remarkably, the obtained value is the second largest area compressibility coefficient known for any material. What is more, deuteration enhances also the NTE property (α 2 = −23.4(22) vs −16.1(31) MK −1 for (DAmGP)Cl and (HAmGP)Cl, respectively) of the investigated supramolecular network. Our research opens new paths to the preparation of organic hydrogen-bonded materials with unique mechanical responsiveness to temperature and pressure stimuli.

First-principles study on the negative/zero area compressibility in Ag3BO3 with “wine-rack” architecture

“…However, very few materials would abnormally expand or remain constant along one or two directions as hydrostatic pressure increases, which is termed negative or zero compressibility [2][3][4][5] . These counterintuitive pressure-responding behaviors bring great application prospects in many fields, such as shock wave absorption [6,7] , body armor [8,9] , ultrasensitive pressure detectors [3,5,10] , deep-sea optical cable [11,12] , etc. The exploration of these anomalous mechanical materials has been one of the most advanced branches of mechanical functional materials.…”

“…In the past decades, much great effort has been devoted to the investigation of the structure-property relationship of NAC/ZAC, and several structural models have been proposed to elaborate the microscopic mechanism, such as "wine-rack" models [7,20,21] , "helical chain" structures [3] , and Lifshits mechanisms [22] , which have strongly promoted the exploration of abnormal compressibility materials. Among them, the "wine-rack" motif, established on the bar-hinge model, is the most prevailing mechanism of these fascinating mechanical behaviors, which has led to the discovery of anomalous compressibility in dozens of materials, including Ag 3 Co(CN) 6 [23] , KMn[Ag(CN) 2 ] 3 [24] , methanol monohydrate [25] , MIL-53(Al) [20] , MIL-122(In) [7] , etc. Nonetheless, almost all these ever-discovered negative compressibility (NC) originating from the "wine-rack" motif only occur along one direction, and no NAC material has been detected by this structural prototype.…”