Single-Pot Self-Assembly of Heteroleptic Mn(I)-Based Aminoquinonato-Bridged Ester/Amide-Functionalized Dinuclear Metallastirrups: Potential Anticancer and Visible-Light-Triggered CORMs

Abstract

Multicomponent self-assembly of Mn 2 (CO) 10 , a bis-chelating aminoquinonato (ON∩ON) bridge (L), and an ester/amide-functionalized flexible neutral ditopic linker (L′) has resulted into the formation of M 2 LL′-type manganese(I)-based dinuclear metallastirrups of general formula [{(CO) 3 Mn(μ-η 4 -L)Mn(CO) 3 }(μ-L′)] ( 1 – 10 ). Compounds 1 – 10 were accomplished via orthogonal bonding of the aminoquinone ligand (2,5-bis( n -butylamino)-1,4-benzoquinone/2,5-bis(phenethylamino)-1,4-benzoquinone) and ditopic pyridyl ligand to manganese carbonyl. The resultant metallastirrups were characterized using elemental analyses and IR, UV–vis, 1 H NMR, and electrospray ionization-mass spectroscopic techniques. The molecular structure of 6 was confirmed by single-crystal X-ray diffraction methods. Furthermore, molecular recognition capabilities of 1 , 5 , 7 , and 9 were evaluated with aromatic compounds containing hydroxy/amine functionalities. Anticancer activities of compounds 1 − 3 , 5 − 7 , 9 , and 10 were investigated against three cancer cell lines, that is, lung (A549), colon (HCT-15), and cervical (HeLa) as well as on normal cells (HEK 293). Compound 9 showed a broad-spectrum inhibition toward these cancer cells upon exposure to visible light. The myoglobin assay was performed using UV–vis absorption spectroscopy to investigate the visible-light-triggered CO release from 5 and 9 that could be related to their ability to effectively inhibit cancer cells. In addition, morphological studies confirmed the induction of autophagy due to the treatment of cancer cells using compound 9 .

Visible-to-NIR-Light Activated Release: From Small Molecules to Nanomaterials

“…In addition, Manimaran and co-workers developed a series of 10 Mn I -based aminoquinonato-bridged dinuclear complexes 263 ( Table 17 ) that release CO upon irradiation with green light. 1184 The mechanism of CO release from the Mn I tryptophanate complex 264 ( Table 17 ) 1185 was studied by time-resolved ultrafast infrared spectroscopy (TRIR) and TD-DFT, 1186 which revealed that excitation leads to an LMCT from the indole moiety of the tryptophan ligand to the metal d-orbitals. The loss of CO then occurs within 3 ps, resulting in the formation of the triplet state of the dicarbonyl product 3 [Mn I (tryp)(CO) 2 (MeCN)], which is solvated within 20 ps.…”

Luminescent PhotoCORMs: Enabling/Disabling CO Delivery upon Blue Light Irradiation

“…Despite recent advances, researchers are seeking to synthesize carbonyl compounds that can release CO molecules at wavelengths closer to the visible region − in addition to being less cytotoxic, focusing on their medicinal applications. In this context, we report herein two new manganese photoCORMs, [Mn­(Oxa-H)­(CO) 3 Br] ( 1 ) and [Mn­(Oxa-NMe 2 )­(CO) 3 Br] ( 2 ) (Chart ), that have the required properties for carbonyl-containing prodrugs, such as CO release under blue light (λ 453 ) and fast CO release rates.…”

A red light‐activable MnI(CO)3‐functionalized gold nanocomposite as the anticancer prodrug with theranostic potential

“…The k CO value was determined from the linear fit of the plot (Figure S33); the apparent first‐order rate constant of photoinduced CO release by the hybrid was determined to be as high as 33.7 × 10 −3 s −1 , which was substantially greater than the CO release rate of complex 1 and those of other photoCORMs (Table S5). [ 31–43,74 ] The facile interelectronic delocalization between AuNPs' surface and the Mn(I) complex was likely responsible for the observed enhancement of the CO release rate. The collective effect of 657 number of Mn(I) complexes functionalizing and individual AuNP also contributed to the increased rate of CO release.…”

“…[ 15–30 ] The salutary effect of a low dose of CO has prompted research on the photoactivated release of exogenous CO from CO‐releasing molecules (CORMs) with spatial and temporal resolution for clinical applications, including cancer therapy. [ 31–48 ] However, the delivery, tumor specificity, and retention of CORMs in malignant tumors are formidable challenges in utilizing photoCORMs for cancer therapy. [ 42 ]…”

“…[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] The salutary effect of a low dose of CO has prompted research on the photoactivated release of exogenous CO from CO-releasing molecules (CORMs) with spatial and temporal resolution for clinical applications, including cancer therapy. [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] However, the delivery, tumor specificity, and retention of CORMs in malignant tumors are formidable challenges in utilizing photoCORMs for cancer therapy. [42] Gold nanoparticles (AuNPs) and gold nanorods have emerged as ideal drug-delivery platforms because of their easy synthesis, large surface areas, good biocompatibility, and tunable and facile functionalization.…”