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1. Probing Electronic Communication and Excited-State Dynamics in the Unprecedented Ferrocene-Containing Zinc MB-DIPY

   https://doi.org/acsomega.0c03764  

   Zatsikha, Yuriy V.; Shamova, Liliya I.; Schaffner, Jacob W.; Healy, Andrew T.; Blesener, Tanner S.; Cohen, Gabriel; Blank, David A.; Nemykin, Victor N. (October 2020, ACS omega)

   The electronic communication between two ferrocene groups in the electron-deficient expanded aza-BODIPY analogue of zinc manitoba-dipyrromethene (MB-DIPY) was probed by spectroscopic, electrochemical, spectroelectrochemical, and theoretical methods. The excited-state dynamics involved sub- ps formation of the charge-separated state in the organometallic zinc MB-DIPYs, followed by recovery of the ground state via charge recombination in 12 ps. The excited-state behavior was contrasted with that observed in the parent complex that lacked the ferrocene electron donors and has a much longer excited-state lifetime (670 ps for the singlet state). Much longer decay times observed for the parent complex without ferrocene confirm that the main quenching mechanism in the ferrocene-containing 4 is reflective of the ultrafast ferrocene-to-MB-DIPY core charge transfer (CT 

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2. Syntheses, Structural Studies, and Copper Iodide Complexes of Macrocycles Derived from Williamson Ether Syntheses Involving 2,9-Bis(4-hydroxyphenyl)-1,10-phenanthroline, α,ω-Dibromides, and Resorcinol or 2,7-Dihydroxynaphthalene

   https://doi.org/10.1071/CH16587  

   Baranová, Zuzana; Amini, Hashem; Neupane, Madhav; Garrett, Sydney C.; Ehnbom, Andreas; Bhuvanesh, Nattamai; Reibenspies, Joseph H.; Gladysz, John A. (January 2017, Australian Journal of Chemistry)

   1,3-Bis(6-bromohexyloxy)benzene, 2,7-bis(6-bromohexyloxy)naphthalene, 1,3-bis(4-bromomethylbenzyloxy)benzene, and 1,3-bis(3-bromomethylbenzyloxy)benzene were prepared via Williamson ether synthesis using resorcinol or 2,7-dihydroxynaphthalene and 1,6-dibromohexane, 1,4-bis(bromomethyl)benzene, or 1,3-bis(bromomethyl)benzene (21–47 % yield). These dibromides were condensed with 2,9-bis(4-hydroxyphenyl)-1,10-phenanthroline in the presence of K2CO3 to give the corresponding 31- to 35-membered macrocycles (3a–d, 22–63 % yield). When 3a–d were treated with CuI, mononuclear 1 : 1 complexes formed, in which the CuI chelates to the nitrogen donor atoms of the phenanthroline moiety (4a–d, 40–80 % yield). The crystal structures of 3a–c and 4a–c were determined and analyzed using density functional theory calculations and in the context of rotaxanes that could be formed by treatment of 4a–d with terminal alkynes (e.g. macrocycle dimensions, void volumes). The copper and iodide atoms in 4a–c significantly protrude from the least-squares plane of the phenanthroline moiety (0.46–0.63 Å and 1.65–2.07 Å). 

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3. Deoxydehydration of polyols catalyzed by a molybdenum dioxo-complex supported by a dianionic ONO pincer ligand

   https://doi.org/10.1039/C9DT03759D  

   Tran, Randy; Kilyanek, Stefan M. (November 2019, Dalton Transactions)

   Deoxydehydration (DODH) is the net reduction of diols and polyols to alkenes or dienes and water. Molybdenum cis -dioxo bis-phenolate ONO complexes were synthesized and have been shown to be active for DODH. Catalysts were screened for activity at 150–190 °C, and appreciable yields of up to 59% were obtained. PPh 3 , Na 2 SO 3 , Zn, C, 3-octanol and 2-propanol were screened as reductants. Additionally, the reactivities of a variety of diols were screened. With ( R , R )-(+)-hydrobenzoin as substrate, DODH occurs via a mechanism where reduction of the Mo catalyst is a result of diol oxidation to form two equivalents of aldehyde. These reactions result in complete conversion and near quantitative yields of trans-stilbene and benzaldehyde. 

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4. Decarbonylative ether dissection by iridium pincer complexes

   https://doi.org/10.1039/d0sc03736b  

   Yoo, Changho; Dodge, Henry M.; Farquhar, Alexandra H.; Gardner, Kristen E.; Miller, Alexander J. (November 2020, Chemical Science)

   A unique chain-rupturing transformation that converts an ether functionality into two hydrocarbyl units and carbon monoxide is reported, mediated by iridium( i ) complexes supported by aminophenylphosphinite (NCOP) pincer ligands. The decarbonylation, which involves the cleavage of one C–C bond, one C–O bond, and two C–H bonds, along with formation of two new C–H bonds, was serendipitously discovered upon dehydrochlorination of an iridium( iii ) complex containing an aza-18-crown-6 ether macrocycle. Intramolecular cleavage of macrocyclic and acyclic ethers was also found in analogous complexes featuring aza-15-crown-5 ether or bis(2-methoxyethyl)amino groups. Intermolecular decarbonylation of cyclic and linear ethers was observed when diethylaminophenylphosphinite iridium( i ) dinitrogen or norbornene complexes were employed. Mechanistic studies reveal the nature of key intermediates along a pathway involving initial iridium( i )-mediated double C–H bond activation. 

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5. Radical Complexes of Nickel(II)/Copper(II) and Redox Non‐innocent MB‐DIPY Ligands: Unusual Stability and Strong Near‐Infrared Absorption at λ _max ∼1300 nm

   https://doi.org/10.1002/chem.202201181  

   Zatsikha, Yuriy_V; Shamova, Liliya_I; Shepit, Michael; Berry, Steven_M; Thomas, Fabrice; Herbert, David_E; van_Lierop, Johan; Nemykin, Victor_N (June 2022, Chemistry – A European Journal)

   Abstract The preparation of radicals with intense and redox‐switchable absorption beyond 1000 nm is a long‐standing challenge in the chemistry of functional dyes. Here we report the preparation of a series of unprecedented stable neutral nickel(II) and copper(II) complexes of “Manitoba dipyrromethenes” (MB‐DIPYs) in which the organic chromophore is present in the radical‐anion state. The new stable radicals have an intense absorption atλ_max∼1300 nm and can be either oxidized to regular [M^II(MB‐DIPY)]⁺(M=Cu or Ni) or reduced to [M^II(MB‐DIPY)]⁻compounds. The radical nature of the stable [M^II(MB‐DIPY)] complexes was confirmed by EPR spectroscopy with additional insight into their electronic structure obtained by UV‐Vis spectroscopy, electro‐ and spectroelectrochemistry, magnetic measurements, and X‐ray crystallography. The electronic structures and spectroscopic properties of the radical‐based chromophores were also probed by density functional theory (DFT) and time‐dependent DFT (TDDFT) calculations. These nickel(II) and copper(II) complexes represent the first stable radical compounds with a MB‐DIPY ligand. 

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