The distinct synergetic characteristics between each component in inorganic–organic hybrids offer various possibilities to obtain new “smart”, high performing materials. Growing interest in this field has largely expanded the content of photochromic materials for the purpose of improving existing photochromic materials, fabricating photoresponsive devices, and exploring new families of photochromic materials. In this feature article, we give a brief review of photochromic hybrids of metal halides, metal cyanides, polyoxometalates, and metal chalcogenides as well as photochromic metal–organic complexes.

Two phases of Ga₂S₃ with different space groups Cc and F3m were synthesized in pure phase by a facile boron–sulfur–metallic oxide reaction. They both have a good transparency in the wavelength range of 0.44–25 μm and exhibit comparatively large second-harmonic generation (SHG) effects of about 0.7 and 0.5 times that of commercial KTiOPO₄ (KTP), for the monoclinic and cubic Ga₂S₃ respectively. The monoclinic Ga₂S₃ is phase-matchable at the wavelength of 1910 nm while the cubic phase is non-phase-matchable. In order to study their powder laser induced damage threshold (LIDT) properties, a single pulse powder LIDT measurement method was proposed and it was found that they have very high powder LIDTs of about 30 and 100 times that of AgGaS₂ (AGS), respectively for the monoclinic and cubic phase, under a single pulse 1064 nm laser radiation with a pulse width τ_p of 8 ns. To gain further insights into the nonlinear optical (NLO) and LIDT properties of the monoclinic and cubic Ga₂S₃, calculations of second-order NLO susceptibility and lattice energy density (LED) were also performed to explain their SHG efficiencies and high LIDTs.

Bulk chemicals such as ethylene glycol (EG) can be industrially synthesized from either ethylene or syngas, but the latter undergoes a bottleneck reaction and requires high hydrogen pressures. We show that fullerene (exemplified by C ₆₀ ) can act as an electron buffer for a copper-silica catalyst (Cu/SiO ₂ ). Hydrogenation of dimethyl oxalate over a C ₆₀ -Cu/SiO ₂ catalyst at ambient pressure and temperatures of 180° to 190°C had an EG yield of up to 98 ± 1%. In a kilogram-scale reaction, no deactivation of the catalyst was seen after 1000 hours. This mild route for the final step toward EG can be combined with the already-industrialized ambient reaction from syngas to the intermediate of dimethyl oxalate.