Steric effects on acetate-assisted cyclometallation of meta-substituted N-phenyl and N-benzyl imidazolium salts at [MCl2Cp*]2 (M = Ir, Rh)

meta-Substituted N-phenyl,N′-methyl and N-benzyl,N′-methyl imidazolium salts undergo acetate-assisted cyclometallation to provide mixtures of ortho and para substituted cyclometallated complexes.

Fluorescent perylenylpyridine complexes: an experimental and theoretical study

Perylenylpyridine cyclometallated complexes exhibit fluorescence with quantum yields from 1.1 to 47% depending on the metal, the oxidation state, the auxiliary ligand and the size of the metallacycle (five or six).

Electrochromic behaviour of Ir(iii) bis-cyclometalated 1,2-dioxolene tetra-halo complexes: fully reversible catecholate/semiquinone redox switches

Ir(iii) redox switchable cyclometallated complexes were synthesized and their paramagnetic and electrochromic properties were investigated.

Direct Ortho-Metallation of Aryl Substituted Heteroaromatic Ligands with TiCl 4 and ZrCl 4 - An Experimental and DFT Study with 2-Phenyl Indole as the Ligand.

TiCl 4 and ZrCl 4 each react with aryl substituted heteroaromatic ligands such as 2-Phenyl-1H-indole, to thermally undergo one-pot direct orthometallations, and yield new types of cyclometallated complexes. TiCl 4 coordinates at ambient temperature to form the indole complex ( 1 ), which undergoes isomerization to the indolenine ( 2 ). DFT calculations indicate that complex ( 2 ) is more stable than ( 1 ) by 6.4 kcal/mol. Upon warming to about 105°C, extrusion of HCl takes place with simultaneous orthometallation ( 3 ), yielding a metallacyclic complex ( 4 ). The mechanism of the orthometallation has been investigated by DFT, and the transition state c onfir med by IRC. At the elevated temperature the transition state ( 3 ) involves the synchronous transformation of four atoms, Ti, ortho C, H, and the apical Cl. The ortho C of the phenyl group acquires a partial positive charge through conjugation, forming a (C-H)δ + ...Clδ - interaction, with a simultaneous elongation and breaking of the Ti-Cl bond, resulting in the formation of a Ti-C bond. The latter bond is created at the same time a Ti-Cl bond is breaking, and an HCl is being formed, as illustrated in transition state ( 3 ). This HCl is retained in the crystal structure of the final product ( 4 ), by electrostatic interaction with one of the chloride ligands. The reaction sequence may be repeated with ZrCl 4 in place of TiCl 4 . Complex ( 4 ) has been isolated and characterized by solid state 13 C NMR CPMAS/DDMAS spectra, X-ray photoelectron spectroscopy (XPS), infrared and analytical data. The intermediate structures ( 1 through 4 ), as well as the sequence of ligand transformations to produce the ortho-metallated complex are supported by DFT calculations. The new cyclometallated complexes are thermally stable, unlike several other complexes featuring a Ti-C bond. They may have important applications, such as in α-olefin polymerization catalysis, and as building blocks in metalodrugs for cancer therapy.<br>

Direct Ortho-Metallation of Aryl Substituted Heteroaromatic Ligands with TiCl 4 and ZrCl 4 - An Experimental and DFT Study with 2-Phenyl Indole as the Ligand.

TiCl 4 and ZrCl 4 each react with aryl substituted heteroaromatic ligands such as 2-Phenyl-1H-indole, to thermally undergo one-pot direct orthometallations, and yield new types of cyclometallated complexes. TiCl 4 coordinates at ambient temperature to form the indole complex ( 1 ), which undergoes isomerization to the indolenine ( 2 ). DFT calculations indicate that complex ( 2 ) is more stable than ( 1 ) by 6.4 kcal/mol. Upon warming to about 105°C, extrusion of HCl takes place with simultaneous orthometallation ( 3 ), yielding a metallacyclic complex ( 4 ). The mechanism of the orthometallation has been investigated by DFT, and the transition state c onfir med by IRC. At the elevated temperature the transition state ( 3 ) involves the synchronous transformation of four atoms, Ti, ortho C, H, and the apical Cl. The ortho C of the phenyl group acquires a partial positive charge through conjugation, forming a (C-H)δ + ...Clδ - interaction, with a simultaneous elongation and breaking of the Ti-Cl bond, resulting in the formation of a Ti-C bond. The latter bond is created at the same time a Ti-Cl bond is breaking, and an HCl is being formed, as illustrated in transition state ( 3 ). This HCl is retained in the crystal structure of the final product ( 4 ), by electrostatic interaction with one of the chloride ligands. The reaction sequence may be repeated with ZrCl 4 in place of TiCl 4 . Complex ( 4 ) has been isolated and characterized by solid state 13 C NMR CPMAS/DDMAS spectra, X-ray photoelectron spectroscopy (XPS), infrared and analytical data. The intermediate structures ( 1 through 4 ), as well as the sequence of ligand transformations to produce the ortho-metallated complex are supported by DFT calculations. The new cyclometallated complexes are thermally stable, unlike several other complexes featuring a Ti-C bond. They may have important applications, such as in α-olefin polymerization catalysis, and as building blocks in metalodrugs for cancer therapy.<br>

Hemilabile bonding of 1-oxa-4,7-dithiacyclononane in cyclometallated palladium(ii) complexes

The synthesis and characterization of a series of cyclometallated complexes of Pd(ii) incorporating the mixed donor ligand 1-oxa-4,7-dithiacyclononane ([9]aneS2O) are presented in this study.

Synthesis and structural chemistry of CoII, CuII, CuI and PdII complexes containing a flexible monoselenoether ligand

A monoselenoether ligand (PySeCH2Py) reacts with CoII, CuII, CuI and PdII resulting in the formation of molecular, polymeric or cyclometallated complexes depending on the starting material used and the reaction conditions applied.

Cyclometallation of a germylene ligand by concerted metalation–deprotonation of a methyl group

Treatment of [(Dipp)NCMeCHCOMeGeN(SiMe3)2] with [Rh2Cl2(μ-Cl)2(η5-Cp*)2] and [Ir2Cl2(μ-Cl)2(η5-Cp*)2] led to cyclometallated complexes of Rh and Ir with deprotonation from the CH3 group in the germylene ligand.

Thin Film Electrodeposition of Ir(III) Cyclometallated Complexes

Novel electropolymerizable Ir(III) cyclometallated complexes have been synthesized and characterized. In these complexes the cyclometallated ligands are either 2-phenylpyridineH(PhPy) or benzothiazole-triphenylamineH(BzTh-tpa), while the Ir(III) coordination sphere is completed by a Schiff base substituted with a triphenylamine fragment. A complete electrochemical study has been conducted on all complexes, in order to verify the feasibility of electropolymerization and to elucidate the role of the specific position of the triphenylamine moiety in the molecular structure. Homogeneous thin films of Ir(III) metallopolymers have been successfully obtained through electropolymerization process.