Novel Cyclometallated Complexes Derived From a Halogenated Thiosemicarbazone. Crystal and Molecular Structures of 2‐FC6H4C(Me)=NN(H)C(=S)NHPh and [(Pd{2‐FC6H3C(Me)=NN=C(S)NHPh})2(μ‐PPh2(CH2)2PPh2)]

Treatment of the thiosemicarbazone 2‐FC₆H₄C(Me)=NN(H)C(=S)NHPh, a , with palladium(II) acetate in acetic acid, or with lithium tetrachloropalladate(II) in methanol, gave the tetranuclear cyclometallated complex [Pd{2‐FC₆H₃C(Me)=NN=C(S)NHPh}]₄ (1a) . Reaction of 1a with the diphosphines Ph₂P(CH₂)₂PPh₂ (dppe), Ph₂PCH=CHPPh₂ (trans‐dpe) Ph₂P(CH₂)₃Ph₂ (dppp) or Ph₂P(CH₂)₄Ph₂ (dppb) in a 1:2 molar ratio gave the dinuclear cyclometallated complexes [(Pd{2‐FC₆H₃C(Me)=NN=C(S)NHPh})₂(μ‐Ph₂P(CH₂)_nPPh₂)], (n = 2, 2a ; 3, 4a ; 4, 5a ) and [(Pd{2‐FC₆H₃C(Me)=NN=C(S)NHPh})₂(μ‐Ph₂PCH=CHPPh₂)], ( 3a ). The X‐ray crystal structure of ligand a and of complex 2a are described. The structure of complex 2a shows the palladium atom is bonded to four different donor atoms: C, N, S and P.     

Silver(III)⋅⋅⋅Silver(III) Interactions that Stabilize the syn Form in a Porphyrin Dimer Upon Oxidation

The interaction between two Ag^II porphyrins, connected covalently through a highly flexible ethane bridge, in a metalloporphyrin dimer has been investigated upon stepwise oxidation. X‐ray structure determination of one and two‐electron oxidized complexes has clearly revealed only metal‐centered oxidation that results in short Ag−N (porphyrin) distance with large distortion in the porphyrin macrocycle. The 2e‐oxidized complex exhibits significant metallophilic interaction in the form of a close Ag^III⋅⋅⋅Ag^III contact that brings two porphyrin rings more cofacial with syn ‐conformation, which would otherwise stabilize in an anti ‐form. The interaction also leads to an intense emission peak at 546 nm at 77 K in the photoluminescence study.     

Supramolecular Cl⋅⋅⋅H and O⋅⋅⋅H Interactions in Self‐Assembled 1,5‐Dichloroanthraquinone Layers on Au(111)

The role of halogen bonds in self‐assembled networks for systems with Br and I ligands has recently been studied with scanning tunneling microscopy (STM), which provides physical insight at the atomic scale. Here, we study the supramolecular interactions of 1,5‐dichloroanthraquinone molecules on Au(111), including Cl ligands, by using STM. Two different molecular structures of chevron and square networks are observed, and their molecular models are proposed. Both molecular structures are stabilized by intermolecular Cl???H and O???H hydrogen bonds with marginal contributions from Cl‐related halogen bonds, as revealed by density functional theory calculations. Our study shows that, in contrast to Br‐ and I‐related halogen bonds, Cl‐related halogen bonds weakly contribute to the molecular structure due to a modest positive potential (σ hole) of the Cl ligands.