We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
A Polymorph of Dipeptide Halide Glycyl-L-Alanine Hydroiodide Monohydrate: Crystal Structure, Optical Second Harmonic Generation, Piezoelectricity and Pyroelectricity.
- Authors
Baptista, Rosa M. F.; Gomes, Clara S. B.; Silva, Bruna; Oliveira, João; Almeida, Bernardo; Castro, Cidália; Rodrigues, Pedro V.; Machado, Ana; Freitas, Ruben B.; Rodrigues, Manuel J. L. F.; de Matos Gomes, Etelvina; Belsley, Michael
- Abstract
A polymorph of glycyl-L-alanine HI.H2O is synthesized from chiral cyclo-glycyl-L-alanine dipeptide. The dipeptide is known to show molecular flexibility in different environments, which leads to polymorphism. The crystal structure of the glycyl-L-alanine HI.H2O polymorph is determined at room temperature and indicates that the space group is polar (P21), with two molecules per unit cell and unit cell parameters a = 7.747 Å, b = 6.435 Å, c = 10.941 Å, α = 90°, β = 107.53(3)°, γ = 90° and V = 520.1(7) Å3. Crystallization in the polar point group 2, with one polar axis parallel to the b axis, allows pyroelectricity and optical second harmonic generation. Thermal melting of the glycyl-L-alanine HI.H2O polymorph starts at 533 K, close to the melting temperature reported for cyclo-glycyl-L-alanine (531 K) and 32 K lower than that reported for linear glycyl-L-alanine dipeptide (563 K), suggesting that although the dipeptide, when crystallized in the polymorphic form, is not anymore in its cyclic form, it keeps a memory of its initial closed chain and therefore shows a thermal memory effect. Here, we report a pyroelectric coefficient as high as 45 µC/m2K occurring at 345 K, one order of magnitude smaller than that of semi-organic ferroelectric triglycine sulphate (TGS) crystal. Moreover, the glycyl-L-alanine HI.H2O polymorph displays a nonlinear optical effective coefficient of 0.14 pm/V, around 14 times smaller than the value from a phase-matched inorganic barium borate (BBO) single crystal. The new polymorph displays an effective piezoelectric coefficient equal to d e f f = 280 p C N − 1 , when embedded into electrospun polymer fibers, indicating its suitability as an active system for energy harvesting.
- Subjects
SECOND harmonic generation; POLYMORPHISM (Crystallography); CRYSTAL structure; PYROELECTRICITY; PIEZOELECTRICITY; TRIGLYCINE sulfate
- Publication
Materials (1996-1944), 2023, Vol 16, Issue 10, p3690
- ISSN
1996-1944
- Publication type
Article
- DOI
10.3390/ma16103690