Glasses are ‘frozen liquids’, formerly thought to belong to three categories: inorganic, organic or metallic. The most common route to the glassy state involves melt-quenching, i.e. cooling a liquid on a timescale fast enough to avoid molecular or atomic reordering to an ordered state. On heating, glasses undergo a reversible transition to a softer, more liquid-like state at their glass transition temperature (Tg).
Despite the enormous number (>80,000) of crystalline hybrid solids such as MOFs and HOIPs known, their disordered states remain almost totally unknown. This group have pioneered the synthesis and characterisation of glasses formed by melting hybrid solids. For example, the melt-quenching of several zeolitic imidazolate frameworks results in glasses which retain the metal-organic-metal connectivity of the crystalline state, though are bulk, transparent, grain-boundary free materials. Equally, we have also shown that hybrid perovskite materials are also glass formers, and that the glasses display interesting thermoelectric properties.
The glasses belong to the family of hybrid glasses – a new 4th category of glass, Their structural, mechanical, chemical and optical properties are thus of extreme interest, and the group works on building structure-property relationships so that we can design the next generation of functional glass.
(1) Liquid, glass and amorphous solid states of metal-organic frameworks and coordination polymers
T. D. Bennett* and S. Horike*, Nat. Rev. Mater., 2018, 3, 431-440.
(2) Mechanochemical Synthesis of Mixed Metal, Mixed Linker Glass-Forming Metal–Organic Frameworks
M. F. Thorne, M. L. Ríos Gómez, A. M. Bumstead, S. Li and T. D. Bennett*, Green Chemistry, 2020, 22, 2505 – 2512.
(3) Hybrid Inorganic-Organic Perovskite Glasses
B. K. Shaw, A. R. Hughes, M. Ducamp, D. A. Keen, F. X. Coudert, F. Blanc and T. D. Bennett*, Nat. Chem., 2021, DOI: s41557-021-00681-7.
(4) Liquid metal-organic frameworks
R. Gailliac, P. Pullumbi, K. A. Beyer, K. W. Chapman, D. A. Keen, T. D. Bennett*, F. X Coudert*, Nat. Mater., 2017,16, 1149-1155.
(5) Hybrid glasses from strong and fragile metal-organic framework liquids
T. D. Bennett*, J. C. Tan, Y. Yue, E. Baxter, C. Ducati, N. Terril, H. H. M. Yeung, Z. Zhou, W. Chen, S. Henke, A. K. Cheetham, and G. N. Greaves*, Nat. Commun., 2015, 6,8079.
(6) Amorphous metal-organic frameworks
T. D. Bennett* and A. K. Cheetham*, Acc. Chem. Res., 2014, 47, 1555-1562