Rapid green and blue light‐induced CO release from bromazepam Mn(I) and Ru(II) carbonyls: synthesis, density functional theory and biological activity evaluation

Abstract

Two new photoactivatable carbon monoxide‐releasing molecules (CORMs), fac‐[Mn(CO)3(BZM)Br] (1) and [RuCl2(BZM)(CO)2] (2), derived from the anti‐anxiety drug bromazepam (BZM) and capable of rapid release of CO upon the illumination with light‐emitting diode (LED) source light (470–525 nm) have been synthesized and characterized. The photo‐delivery of CO to myoglobin solution could be achieved via the illumination of 1 at 525 nm for 10 min or at 470 nm for 1 min. The addition of water to a dimethylsulfoxide (DMSO) solution of 1 increases its stability, but it decreases the rate of the CO‐releasing process. CORM 2 behaves as a good visible photoCORM, whereby its two CO molecules are released within 10 min upon exposure to LED light source at 470 nm in DMSO. The illumination profile of 2 was also examined using solution infrared spectroscopy. The cis/trans stereochemistry around the Ru(II) ion was determined using quantum chemical calculations. The formation of photoCORMs leads to an improvement in the toxicity of BZM against tested microbes.