Carbon monoxide (CO) is shown to enhance the sensitivity of cancer cells to generate reactive oxygen species such as singlet oxygen (¹O₂) from chemotherapeutics and reduce the drug resistance. Herein, we introduced two Mn-based photoactivated CO releasing molecules conjugated with an emissive BODIPY (BDP) moiety with a general formula of Mn(CO)₃(bpy-R-BDP)Br (R = H or I), labeled as Mn-bpy-H-BDP and Mn-bpy-I-BDP. While both complexes release CO with visible light, Mn-bpy-I-BDP releases CO and produces ¹O₂ from a single molecule. In addition to ¹O₂ generation, iodination of BDP red shifts the absorption of Mn-bpy-I-BDP further into the visible region and significantly increases the dark stability of the complex. Cyclic voltammetry and density functional theory (DFT) calculations suggest a Mn-based highest occupied molecular orbital (HOMO) and a BDP-based lowest unoccupied molecular orbital (LUMO) in these complexes. However, time-dependent DFT calculations suggest that the HOMO – 2(π_BDP) → LUMO(π_BDP^*) is the main optical transition upon excitation with visible light in both complexes. The presence of a phosphorescence peak from the triplet excited state of bpy-I-BDP in both the free ligand and its Mn complex at 77 K was used as additional evidence for ¹O₂ production. We also probed formation of photo-intermediates and products during photolysis with Fourier-transform infrared, ¹H NMR, emission, and absorption experiments and DFT calculations.

中文翻译：

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用可见光从 Mn-BODIPY 光活化 CO 释放分子中释放 CO 并产生 1O2

一氧化碳 (CO) 被证明可以增强癌细胞从化学治疗剂中产生活性氧 (如单线态氧 ( ¹ O ₂ )) 的敏感性并降低耐药性。在此，我们介绍了两种基于 Mn 的光活化 CO 释放分子与发射 BODIPY (BDP) 部分共轭，通式为 Mn(CO) ₃ (bpy-R-BDP)Br (R = H 或 I)，标记为 Mn -bpy-H-BDP 和 Mn-bpy-I-BDP。虽然这两种复合物在可见光下都会释放 CO，但 Mn-bpy-I-BDP 会释放 CO 并从单个分子中产生¹ O ₂。除了¹ O ₂BDP 的碘化使 Mn-bpy-I-BDP 的吸收进一步进入可见光区域，并显着增加了复合物的暗稳定性。循环伏安法和密度泛函理论 (DFT) 计算表明，这些复合物中存在基于 Mn 的最高占据分子轨道 (HOMO) 和基于 BDP 的最低未占据分子轨道 (LUMO)。然而，时间相关的 DFT 计算表明 HOMO – 2(π _BDP ) → LUMO(π _BDP ^* ) 是两种复合物中可见光激发时的主要光学跃迁。在 77 K 时，游离配体及其 Mn 复合物中 bpy-I-BDP 三重激发态的磷光峰的存在被用作¹ O _{2 的}额外证据生产。我们还通过傅里叶变换红外、¹ H NMR、发射和吸收实验以及 DFT 计算探索了光解过程中光中间体和产物的形成。