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[Display omitted] We have witnessed a wide range of theoretical as well as experimental investigations to envisage external stimuli induced changes in electronic, optical and magnetic properties in the metal organic complexes, while hybrid perovskites have recently joined this exciting league of explorations. The flexible organic linkers in such complexes are ideal for triggering not only spin transitions but also a plethora of various different responses under the influence of various external stimuli like pressure, temperature and light. A diverse range of applications particularly in the field of optoelectronics, spintronics and energy scavenging have been manifested. The hysteresis associated with the light induced transitions and spin-crossover governed by pressure and temperature, are promising phenomena for the design principles behind memory devices and optical switches. The pressure induced optical properties tuning or piezochromism has also emerged as one of the prominent areas in the field of hybrid perovskite materials family. It is thus imperative to have a clear understanding of how the tuning in electronic, optical and magnetic properties occur under various stimuli, and selectivity of the stimulus could be influential behind the maximum efficiency in the field of energy and optoelectronic research, and in what future directions this field could be driven from the perspective of futuristic material properties. This review though primarily focuses on the theoretical aspects of understanding the different mechanisms of the phenomena, does provide a unique overview of the experimental literature too, accompanied by the theoretical understanding such that relevant device applications can be considered through a future roadmap of tuning paradigm of external stimuli. It also provides an insight as to how energy and memory storage may be combined by using the principles of spin transition in metal organic complexes. [ABSTRACT FROM AUTHOR]

Thermal transitions of poly(N-isopropylmethacrylamide) (PIPMAm) in aqueous solutions were studied in a wide temperature range from -100 to 60 °C. The solutions of different polymer weight fractions (c=0.03–1) were investigated in cooling and heating scans of differential scanning calorimetry; four qualitatively different kinds of thermograms were identified in dependence of the fraction, c. The transitions are explained in a thermodynamic framework based on the phase diagram of the system. This diagram provides a complete understanding of thermal transitions in aqueous PIPMAm solutions as a function of c, in particular the existence of non-crystallizable water and the temperature induced phase transition that is due to the hydrophobic interaction in PIPMAm solutions. [Copyright &y& Elsevier]