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1. Synthesis, reactivity, structures, and dynamic properties of gyroscope like iron complexes with dibridgehead diphosphine cages: pre- vs. post-metathesis substitutions as routes to adducts with neutral dipolar Fe(CO)(NO)(X) rotors

   https://doi.org/10.1039/c6dt03258c  

   Lang, Georgette M.; Skaper, Dirk; Hampel, Frank; Gladysz, John A. (January 2016, Dalton Transactions)

   Three routes are explored to the title halide/cyanide complexes trans -Fe(CO)(NO)(X)(P((CH 2 ) 14 ) 3 P) ( 9c-X ; X = Cl/Br/I/CN), the Fe(CO)(NO)(X) moieties of which can rotate within the diphosphine cages (Δ H ‡ /Δ S ‡ (kcal mol −1 /eu −1 ) 5.9/−20.4 and 7.4/−23.9 for 9c-Cl and 9c-I from variable temperature 13 C NMR spectra). First, reactions of the known cationic complex trans -[Fe(CO) 2 (NO)(P((CH 2 ) 14 ) 3 P)] + BF 4 − and Bu 4 N + X − give 9c-Cl /- Br /- I /- CN (75–83%). Second, reactions of the acyclic complexes trans -Fe(CO)(NO)(X)(P((CH 2 ) m CHCH 2 ) 3 ) 2 and Grubbs’ catalyst afford the tris(cycloalkenes) trans -Fe(CO)(NO)(X)(P((CH 2 ) m CHCH(CH 2 ) m ) 3 P) ( m /X = 6/Cl,Br,I,CN, 7/Cl,Br, 8/Cl,Br) as mixtures of Z / E isomers (24–41%). Third, similar reactions of trans -[Fe(CO) 2 (NO)(P((CH 2 ) m CHCH 2 ) 3 ) 2 ] + BF 4 − and Grubbs’ catalyst afford crude trans -[Fe(CO) 2 (NO)P((CH 2 ) m CHCH(CH 2 ) m ) 3 P)] + BF 4 − ( m = 6, 8). However, the CC hydrogenations required to consummate routes 2 and 3 are problematic. Crystal structures of 9c-Cl /- Br /- CN are determined. Although the CO/NO/X ligands are disordered, the void space within the diphosphine cages is analyzed in terms of horizontal and vertical constraints upon Fe(CO)(NO)(X) rotation and the NMR data. The molecules pack in identical motifs with parallel P–Fe–P axes, and without intermolecular impediments to rotation in the solid state. 

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2. Photophysical Insights of Halogenated Dipyrrolonaphthyridine‐Diones as Potential Photodynamic Therapy Agents ^†

   https://doi.org/10.1111/php.13757  

   Morgan, Jayla; Yun, Young Ju; Jamhawi, Abdelqader M.; Islam, Shahidul M.; Ayitou, A. Jean‐Luc (January 2023, Photochemistry and Photobiology)

   Abstract We report the synthesis and photophysical characterization of novel halogenated dipyrrolonaphthyridine‐diones (X₂–DPNDs, X = Cl, Br, and I), as candidates for photodynamic therapy (PDT) application. Apart from the heavy atom‐induced spin‐orbit coupling (SOC) dynamics in the investigated X₂–DPNDs, it was found that the position of the halogen atom (relative to the nitrogen of the pyrrole ring) also influenced the triplet excited state behavior. Interestingly, the faster/efficiency sensitization of³O₂to¹O₂using X₂–DPND correlates with the rate of triplet population,k_ISC >1.6 × 10⁸s⁻¹for I₂–DPNDvs k_ISC >2.9 × 10⁹s⁻¹for Cl₂–DPND and Br₂–DPND (whereτ_ISC = 343 ± 3 ps for I₂–DPND andτ_ISC = 5–6 ns for Cl₂–DPND and Br₂–DPND are the lowest time constants/values for ISC). Furthermore, the heavy atom‐induced SOC in Cl₂–DPND and Br₂–DPND did not lead to a reduction of the corresponding fluorescence (ca75%vs67% for the parent DPND). The attractive photophysical characteristics of Cl₂/Br₂–DPND put them on the landscape as not only promising PDT agents but also as fluorescence probes. The present study is a stepping stone in the development of novel organic photosystems for synergistic photomedicinal applications. 

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3. Measurement of the Asymmetric UO22+ Stretching Frequency for [UVIO2(F)3]- Using IRMPD Spectroscopy

   https://doi.org/DOI:10.1016/j.ijms.2019.116231  

   Tatosian, Irena Metzler (July 2019, International journal of mass spectrometry)

   In a previous study [Int. J. Mass Spectrom. 2010; 297: 67-75], the asym. O=U=O stretch (ν3) was measured for anionic uranyl complexes with compn. [UO2(X)3]-, X = Cl-, Br- and I-.  Within this group of complexes, the ν3 frequency red-shifts following the trend I > Br > Cl, suggesting concomitant weakening of the U=O bonds.  However, a value for [UO2(F)3]- was not measured, which prevented a comprehensive comparison of measured ν3 positions to computed frequencies from d. functional theory (DFT) calcns.  Because the shift in ν3 is predicted to be most dramatic when X = F, we revisited these species using IR multiple-photon photodissocn. spectroscopy.  As in our earlier study, a modest red-shift to the ν3 vibration of ∼ 6 cm-1 was obsd. for X = I-, Br-, and Cl-, and the position of the frequency follows the trend I- > Br- > Cl-.  The value measured for [UO2(F)3]- is ∼43 cm-1 lower than the one measured for [UO2(Cl)3]-.  Overall, the trend with respect to ν3 position is reproduced well by computed frequencies from DFT. 

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4. Synthesis, structural studies, and redox chemistry of bimetallic [Mn(CO) ₃ ] and [Re(CO) ₃ ] complexes

   https://doi.org/10.1039/D0DT03666H  

   Henke, Wade C.; Kerr, Tyler A.; Sheridan, Thomas R.; Henling, Lawrence M.; Takase, Michael K.; Day, Victor W.; Gray, Harry B.; Blakemore, James D. (March 2021, Dalton Transactions)

   null (Ed.)

   Manganese ([Mn(CO) 3 ]) and rhenium tricarbonyl ([Re(CO) 3 ]) complexes represent a workhorse family of compounds with applications in a variety of fields. Here, the coordination, structural, and electrochemical properties of a family of mono- and bimetallic [Mn(CO) 3 ] and [Re(CO) 3 ] complexes are explored. In particular, a novel heterobimetallic complex featuring both [Mn(CO) 3 ] and [Re(CO) 3 ] units supported by 2,2′-bipyrimidine (bpm) has been synthesized, structurally characterized, and compared to the analogous monomeric and homobimetallic complexes. To enable a comprehensive structural analysis for the series of complexes, we have carried out new single crystal X-ray diffraction studies of seven compounds: Re(CO) 3 Cl(bpm), anti -[{Re(CO 3 )Cl} 2 (bpm)], Mn(CO) 3 Br(bpz) (bpz = 2,2′-bipyrazine), Mn(CO) 3 Br(bpm), syn - and anti -[{Mn(CO 3 )Br} 2 (bpm)], and syn -[Mn(CO 3 )Br(bpm)Re(CO) 3 Br]. Electrochemical studies reveal that the bimetallic complexes are reduced at much more positive potentials (Δ E ≥ 380 mV) compared to their monometallic analogues. This redox behavior is consistent with introduction of the second tricarbonyl unit which inductively withdraws electron density from the bridging, redox-active bpm ligand, resulting in more positive reduction potentials. [Re(CO 3 )Cl] 2 (bpm) was reduced with cobaltocene; the electron paramagnetic resonance spectrum of the product exhibits an isotropic signal (near g = 2) characteristic of a ligand-centered bpm radical. Our findings highlight the facile synthesis as well as the structural characteristics and unique electrochemical behavior of this family of complexes. 

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5. Rb ₂ CuX ₃ (X = Cl, Br): 1D All‐Inorganic Copper Halides with Ultrabright Blue Emission and Up‐Conversion Photoluminescence

   https://doi.org/10.1002/adom.201901338  

   Creason, Tielyr D.; Yangui, Aymen; Roccanova, Rachel; Strom, Amanda; Du, Mao‐Hua; Saparov, Bayrammurad (November 2019, Advanced Optical Materials)

   Abstract All‐inorganic metal halides such as Cs₄PbX₆and CsPbX₃(X = Cl, Br, and I) are attracting global attention owing to their promise in optoelectronic applications. However, the presence of the toxic heavy metal lead (Pb) in these materials is a major concern. Here, a family of nontoxic high‐efficiency blue‐emitting all‐inorganic halides Rb₂CuX₃(X = Br and Cl) is reported; the compounds exhibit 1D crystal structures featuring anionic²⁻ribbons separated by Rb⁺cations. The measured record high photoluminescence quantum yield values range from 64% to 100% for Rb₂CuBr₃and Rb₂CuCl₃, respectively. Furthermore, the measured emission linewidths are quite narrow with full width at half maximum values of 54 and 52 nm for Rb₂CuBr₃and Rb₂CuCl₃, respectively. Single crystals of Rb₂CuCl₃demonstrate an anti‐Stokes photoluminescence signal, shown for the first time for Pb‐free metal halides. The discovery of highly efficient narrow blue emitters based on a nontoxic and inexpensive metal copper paves a way for the consideration of low‐cost and environmentally friendly copper halides for practical applications. 

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