Abstract
Polar crystalline materials, a subset of the non-centrosymmetric materials, are highly sought after. Their symmetry properties make them pyroelectric and also piezoelectric and capable of second-harmonic generation (SHG). For SHG and piezoelectric applications, metal oxides are commonly used. The advantages of oxides are durability and hardness – downsides are the need for high-temperature synthesis/processing and often the need to include toxic metals. Organic polar crystals, on the other hand, can avoid toxic metals and can be amenable to solution-state processing. While the vast majority of polar organic molecules crystallize in non-polar space groups, we found that both 7-chloro-1,3,5-triazaadamantane, for short Cl-TAA, and also the related Br-TAA (but not I-TAA) form polar crystals in the space group R3m, easily obtained from dichloromethane solution. Measurements confirm piezoelectric and SHG properties for Cl-TAA and Br-TAA. When the two species are crystallized together, solid solutions form, suggesting that properties of future materials can be tuned continuously.
| Original language | English (US) |
|---|---|
| Article number | e202302998 |
| Journal | Chemistry - A European Journal |
| Volume | 30 |
| Issue number | 14 |
| DOIs | |
| State | Published - Mar 7 2024 |
Funding
We thank the National Sciences and Engineering Research Council of Canada (Discovery Grant to UF) and the University of Toronto XSEED program for funding. SKS is grateful for a Mitacs (Canada) Globalink Research Internship. An XSEED grant was jointly held by PI UF and Co-PI Chandra Veer Singh. Professor Singh and graduate student Abu Anand, while not directly involved in this work reported here, are acknowledged for valuable discussions, since the molecules described here are precursors for a joint project. We further thank Ms. Simran Sharma (UTM, NSERC USRA) for an earlier synthesis of Br-TAA in our group and Ms. Colette M. Macarios for assistance with synthesis/crystallization. We further thank Professor Barzda (UTM) and Mr. Kamdin Mirsanaye for exploratory SHG microscopy on Br-TAA. Professor Datong Song (U of T) is acknowledged for contributions to solving the crystal structure of I-TAA. We thank the National Sciences and Engineering Research Council of Canada (Discovery Grant to UF) and the University of Toronto XSEED program for funding. SKS is grateful for a Mitacs (Canada) Globalink Research Internship. An XSEED grant was jointly held by PI UF and Co‐PI Chandra Veer Singh. Professor Singh and graduate student Abu Anand, while not directly involved in this work reported here, are acknowledged for valuable discussions, since the molecules described here are precursors for a joint project. We further thank Ms. Simran Sharma (UTM, NSERC USRA) for an earlier synthesis of Br‐TAA in our group and Ms. Colette M. Macarios for assistance with synthesis/crystallization. We further thank Professor Barzda (UTM) and Mr. Kamdin Mirsanaye for exploratory SHG microscopy on Br‐TAA. Professor Datong Song (U of T) is acknowledged for contributions to solving the crystal structure of I‐TAA.
Keywords
- adamantane
- non-centrosymmetric materials
- nonlinear optics
- piezoelectric
- second-harmonic generation
ASJC Scopus subject areas
- Catalysis
- General Chemistry
- Organic Chemistry