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1. N , N -Disubstituted- N ′-acylthioureas as modular ligands for deposition of transition metal sulfides

   https://doi.org/10.1039/c7dt04860b  

   Ali, Zahra; Richey, Nathaniel E.; Bock, Duane C.; Abboud, Khalil A.; Akhtar, Javeed; Sher, Muhammad; McElwee-White, Lisa (January 2018, Dalton Transactions)

   null (Ed.)

   First row transition metal complexes (Ni, Co, Cu, Zn) with N , N -disubstituted- N ′-acylthiourea ligands have been synthesized and characterized. Bis( N , N -diisopropyl- N ′-cinnamoylthiourea)nickel was found to have the lowest onset temperature for thermal decomposition. Thin film deposition of Ni, Co, and Zn sulfides by aerosol assisted chemical vapor deposition from their respective N , N -diisopropyl- N ′-cinnamoylthiourea complexes at 350 °C has been demonstrated. 

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2. A Rigidified Macrocyclic Grubbs Complex: A Rare Example of In - and Out -Isomers that Show a Dramatic Difference in Catalytic Reactivity

   https://doi.org/10.1021/acs.organomet.4c00331  

   Davalos-Morinigo, Anibal R; Vemulapalli, Srini; Dudding, Travis; Diver, Steven T (September 2024, Organometallics)

   Chirik, Paul (Ed.)

   The design of a rigidified macrocyclic N-heterocyclic carbene (NHC) ligand led to the formation and structural characterization of in- and out-Ru carbene complexes. In this study, introduction of a conformational lock was used to rigidify heteroaryl-aryl bonds and thereby enforce a more perpendicular dihedral angle. A forcing metalation step was needed to form the isomeric Ru carbene complexes (Grubbs complexes). The major isomer had the Ru carbene fragment located outside the macrocyclic ring whereas the minor isomer had the Ru carbene inside the macrocyclic ring. The two new Ru carbene complexes are the first examples of in- and out-isomers of a Grubbs-type complex. The solid state structures of each isomeric ruthenium carbene complex was determined by x-ray diffraction studies. The two Ru complexes showed significantly different catalytic reactivity in the ring-closing metathesis (RCM) of the benchmark substrate, diethyl diallylmalonate. We performed computational studies to determine rotational barriers; scalable energetic barriers were found in the unmetallated NHC ligand, favoring the in-isomer by 2.4 kcal/mol. These calculations, coupled with attempted interconversion of isomers, support a mechanism featuring rotational isomerization of the NHC nucleophile in a preequilibrium step before metalation. 

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3. Substituent Effect on the Circularly Polarized Luminescence of C ₁ ‐Symmetric Carbene‐Copper(I) Complexes

   https://doi.org/10.1002/cptc.202100068  

   Braker, Erin_E; Mukthar, Nishya_F_M; Schley, Nathan_D; Ung, Gaël (June 2021, ChemPhotoChem)

   Abstract The substituent effect on the magnitude of the circularly polarized luminescence (CPL) of^MentCAAC‐Cu‐X (X=F, Cl, Br, I, BH₄, B₃H₈; CAAC=cyclic (alkyl)(amino)carbenes) complexes is experimentally investigated. This study examines seven pairs of enantiomeric complexes with small anionic substituents (halides, borohydrides, hydride). The complexes are fully characterized, including single crystal X‐ray diffraction studies, and chiroptical measurements show that small covalent anions induce a larger CPL magnitude. These results demonstrate that the magnitude of the CPL can be manipulated without making any modifications to the chiral ligand. 

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4. Pincer-Ligated Iridium Complexes with Low-Field Ancillary Ligands: Complexes of ( ^iPr PCP)IrCl ₂ and Comparison with ( ^iPr PCP)IrHCl

   https://doi.org/10.1021/acs.organomet.4c00162  

   Parihar, Ashish; Emge, Thomas J; Chakravartula, Srinivas_V S; Goldman, Alan S (June 2024, Organometallics)

   Pincer-ligated iridium complexes have been widely developed, and (pincer)Ir(III) complexes, particularly five-coordinate, are central to their chemistry. Such complexes typically bear two formally anionic ligands in addition to the pincer ligand itself. Yet despite the prevalence of halides as anionic ligands in transition metal chemistry there are relatively few examples in which both of these ancillary anionic ligands are halides or even other monodentate low-field anions. We report a study of the fragment (iPrPCP)IrCl2 (iPrPCP = 3 2,6 C6H3(CH2PiPr2)), and adducts thereof. These species are found to be thermodynamically disfavored relative to the corresponding hydridohalides. For example, DFT calculations and experiment indicate that one Ir-Cl bond of (iPrPCP)IrCl2 complexes will undergo reaction with H2 to give (iPrPCP)IrHCl or an adduct thereof. In the presence of aqueous HCl, (iPrPCP)IrCl2 adds a chloride ion to give an unusual example of an anionic transition metal complex ((iPrPCP)IrCl3–) with a Zundel cation (H5O2+). (iPrPCP)IrCl2 is not stable as a monomer at room temperature but exists in solution as a mixture of clusters which can add various small molecules. DFT calculations indicate that dimerization and trimerization of (iPrPCP)IrCl2 is more favorable than the analogous reactions of (iPrPCP)IrHCl, in accord with cluster formation being observed only for the dichloride complex. 

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5. Synthesis and characterization of Ag( i ) and Au( i ) complexes with macrocyclic hybrid amine N-heterocyclic carbene ligands

   https://doi.org/10.1039/C7NJ04020B  

   Lu, Taotao; Yang, Chu-Fan; Steren, Carlos A.; Fei, Fan; Chen, Xue-Tai; Xue, Zi-Ling (January 2018, New Journal of Chemistry)

   Four macrocyclic hybrid salts with different numbers of benzimidazolium and amine units, [H 2 L][PF 6 ] 2 (L = L 1 , L 2 , L 3 ) and [H 4 L 4 ][PF 6 ] 4 , have been employed as the heterocyclic carbene (NHC) precursors toward new Ag( i )– and Au( i )–NHC complexes. Three trinuclear and one tetranuclear Ag( i ) complexes 1–4 have been obtained from the reactions of the NHC precursors and Ag 2 O in acetonitrile. Four dinuclear Au( i )–NHC complexes 5–8 have been prepared by reacting the NHC precursors and AuCl(SMe 2 ) in the presence of NaOAc in DMF. The molecular structures of all the complexes are established by single-crystal X-ray diffraction studies. The metal ions in the Ag( i ) complexes 1–3 and the Au( i ) complexes 5–7 are coordinated with two macrocyclic NHC ligands to form a sandwiched structure. In contrast, a trinuclear Ag 3 core is located in the cavity of one macrocyclic ligand in [Ag 3 (L 4 )][PF 6 ] 3 ( 4 ). The photoluminescence properties of Au( i ) complexes 5–8 have also been investigated. 

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