A new class of luminescent cyclometalated Ir(iii) complexes with readily tunable mechanochromic properties derived from the mechanically induced trans-to-cis isomerization have been developed.

A new series of Ir(III) carbene complexes with luminescent mechanochromism derived from transcis isomerization has been developed. Through the introduction of π-conjugating groups into the acyclic carbene ligand, the mechanochromic transand cisconfigurations can be readily interconverted, leading to dual emissive properties in the solid state. Moreover, the solid-or film-forming solvent system can control the dual emission and mechanoresponsive properties in the solid state. The potential uses of a single emissive complex to develop multicolor emissive and multiple stimuli-responsive films have been studied.

Acyclic carbene complexes exhibit exceptional performance and functional properties comparable to their NHC counterparts, and their environmentally sensitive open acyclic carbene structure makes them ideal for developing smart materials and sensors.

The excited-state dynamics of cyanide-bridged trinuclear carbonyl rhenium(I) complexes with general formula of [Re] p -[Re] c [Re] p {[Re] c = [(À NC)Re I (CO) 2 (phen)(CNÀ )]; [Re] p = [À Re I (CO) 2 (L L)(L a )], L L = diimine or diphosphine, L a = triphenylphosphine or carbonyl ligand} and the monomeric peripheral control complexes have been elucidated through a study with ultrafast transient absorption spectroscopy. The time constants for the energy transfer between the MLCT excited states of the peripheral and central Re(I) chromophores (ca. 0.56-0.78 ps) are typical for other cyanide-bridged polynuclear transition metal complexes. The emissive excited states and the absorption transient have been characterized by nanosecond transient Raman spectroscopy.