Cyclometallated Platinum(II) Complexes Featuring an Unusual, C^N‐Coordinating Pyridyl‐pyridylidene Ligand and L X Coligands: Synthesis, Structures and Dual Luminescence Behavior

Thanks to an unusual protodemethylation reaction, a series of luminescent cyclometallated platinum(II) complexes can be prepared, which incorporate a rare NC-chelating, pyridyl-pyridylidene ligand, in combination with OO-coordinating acetylacetonate (acac) or NO-coordinating 2-picolinate (pic) or 8-hydroxyquinolate. The acac and pic complexes show unusual dual emission in a frozen glass.A series of cyclometallated platinum(II) complexes incorporating a rare, N^C-chelating, pyridyl-pyridylidene ligand are described, in which the coordination sphere is completed by two chlorides or an L X co-ligand, namely O O-coordinating acetylacetonate (acac), or N^O-coordinating 2-picolinate (pic) or 8-hydroxyquinolinate. The acac and pic complexes have been structurally characterized in the solid state by single-crystal X-ray diffraction. These two complexes display red phosphorescence in the solid state at room temperature. In a frozen glass at 77 K, all four complexes show two broad emission bands that span much of the visible spectrum, apparently from two unequilibrated excited states

A Convenient Approach to Luminescent Cyclometalated Platinum(II) Complexes with Organometallic π-Bonded Benzenedithiolate

International audienceA family of neutral cyclometalated platinum(II) complexes [(C^N)Pt(η-S^S)] with π-bonded benzenedithiolate {(η-S^S) = Cp*Ru(C6H4S2)} and various cyclometalated ligands, {(C^N) = 2-phenylpyridine (ppy), (2); 2,4-difluorophenylpyridine (F2ppy) (3), benzo[h]quinoline (bzq) (4); dibenzo[f,h]quinoline (dbzq) (5) } were prepared and fully characterized. For comparison purposes the related bipyridine platinum (II) complex [(bpy)Pt(η-S^S)][OTf] (6) was also prepared. The electrochemistry behavior of these complexes was investigated and shows the enhanced stability of these compounds toward oxidation due to the presence of Cp*Ru moiety which is now π-bonded to the benzenedithiolato group. Moreover several complexes were identified by single crystal X-ray molecular structures. To the best of our knowledge these are the first structures to be reported for cyclometalated platinum complexes with a π-bonded benzenedithiolate (bdt) ligand. All of the complexes are luminescent in fluid solution at room temperature and in glassy solution at 77 K; their emission properties can be tuned through ligand variation

Single ion magnets based on lanthanoid polyoxomolybdate complexes

Polyoxometalate (POM) chemistry has recently offered excellent examples of single ion magnets (SIMs) and molecular spin qubits. Compared with conventional coordination compounds, POMs provide rigid and highly symmetric coordination sites. However, all POM-based SIMs reported to date exhibit a very limited range of possibilities for chemical processability. We present herein two new families of POM-based SIMs which are soluble in organic solvents: [Ln(β-Mo8O26)2]5− {LnIII = Tb, Dy, Ho, Er, Tm and Yb} and the functionalised POMs [Ln{Mo5O13(OMe)4NNC6H4-p-NO2}2]3− {LnIII = Tb, Dy, Ho, Er, Yb and Nd}. In addition, these two families represent the first SIMs based on polyoxomolybdates. A magneto-structural analysis of these families is presented, which is based on an effective crystal field model, and compared with the results reported in analogous lanthanoid SIMs based on polyoxotungstates.ERC-2014-CoG/ 647301CM1203CA15128MAT2014-56143-RCTQ2014-52758-PMDM-2015-0538Polyoxometalate (POM) chemistry has recently offered excellent examples of single ion magnets (SIMs) and molecular spin qubits. Compared with conventional coordination compounds, POMs provide rigid and highly symmetric coordination sites. However, all POM-based SIMs reported to date exhibit a very limited range of possibilities for chemical processability. We present herein two new families of POM-based SIMs which are soluble in organic solvents: [Ln(β-Mo8O26)2]5− {LnIII = Tb, Dy, Ho, Er, Tm and Yb} and the functionalised POMs [Ln{Mo5O13(OMe)4NNC6H4-p-NO2}2]3− {LnIII = Tb, Dy, Ho, Er, Yb and Nd}. In addition, these two families represent the first SIMs based on polyoxomolybdates. A magneto-structural analysis of these families is presented, which is based on an effective crystal field model, and compared with the results reported in analogous lanthanoid SIMs based on polyoxotungstates

N-Heterocyclic Carbene Copper (I) Complexes Incorporating Pyrene Chromophore: Synthesis, Crystal Structure, and Luminescent Properties

International audienceLuminescent N-heterocyclic carbene chloride copper (I) complexes incorporating pyrene chromophore (1-Pyrenyl-NHC-R)-Cu-Cl, (3, 4) have been prepared and fully characterized. Two complexes were prepared with R = methyl (3) and R = naphthyl groups (4) at the nitrogen center of the carbene unit to tune their electronic properties. The molecular structures of 3 and 4 have been elucidated by X-ray diffraction and confirm the formation of the target compounds. Preliminary results reveal that all compounds including the imidazole-pyrenyl ligand 1 are emissive in the blue region at room temperature in solution and in solid-state. All complexes display quantum yields comparable or higher when compared to the parent pyrene molecule. Interestingly replacement of the methyl by naphthyl group increases the quantum yield by almost two-folds. These compounds might show promise for applications as optical displays

N-Heterocyclic Carbene Coinage Metal Complexes Incorporating Pyrene Chromophore: Synthesis, Structural Motifs, and Luminescent Properties

National audienceN-heterocyclic carbenes (NHCs) are strongly coordinating ligands and have proven themselves as the ligands of choice in a wide-range of the chemistry spectrum spanning from organometallics, catalysis to medicinal chemistry as well.1-2 More recently they have been used with success to design stable luminescent organometallic and coordination complexe.3-4 This is because they tend to push the 3dd dark states high in energy and thus avoiding the deactivation processes of the low-lying MC (metal-centered) transition states. In this Poster we describe the design of novel class of luminescent NHC-coinage metal complexes containing a pyrene chromophore (Figure 1). All complexes were fully characterized and their molecular structures were ascertained by X-ray diffraction studies. The nature of the coinage metal center and the alky substituents on the carbene unit were probed to tune their electronic properties generating blue emitters at room temperature

N-Heterocyclic Carbene Coinage Metal Complexes Incorporating Pyrene Chromophore: Synthesis, Structural Motifs, and Luminescent Properties

National audienceN-heterocyclic carbenes (NHCs) are strongly coordinating ligands and have proven themselves as the ligands of choice in a wide-range of the chemistry spectrum spanning from organometallics, catalysis to medicinal chemistry as well.1-2 More recently they have been used with success to design stable luminescent organometallic and coordination complexe.3-4 This is because they tend to push the 3dd dark states high in energy and thus avoiding the deactivation processes of the low-lying MC (metal-centered) transition states. In this Poster we describe the design of novel class of luminescent NHC-coinage metal complexes containing a pyrene chromophore (Figure 1). All complexes were fully characterized and their molecular structures were ascertained by X-ray diffraction studies. The nature of the coinage metal center and the alky substituents on the carbene unit were probed to tune their electronic properties generating blue emitters at room temperature

Self-Assembled M 2 L 4 Nanocapsules: Synthesis, Structure and Host-Guest Recognition Toward Square Planar Metal Complexes

International audienceMetallosupramolecular cages of the general formulas [M 2 (L) 4 ][X] 4 can be self-assembled in good yields, where M = Pd, X = NO 3 , L = L 1 (1a); M = Pd, X = OTf, L = L 1 (1b); M = Pt, X = OTf, L = L 1 (2); M = Pd, X = OTf, L = L 2 (3); L 1 = 1,3-bis(pyridin-3-ylethynyl)-5-methoxybenzene; and L 2 = 2,6-(pyridin-3-ylethynyl)-4-methoxyaniline, respectively. These cages have been fully characterized using 1 H, 13 C NMR, elemental analysis, IR spectroscopy, and electrospray mass spectrometry. Additionally the molecular structure of [Pd 2 (L 1) 4 ][OTf] 4 (1b) was confirmed using single crystal X-ray diffraction. The capacity of central cavities of M 2 L 4 cages to accommodate square planar metal complexes was investigated. In particular, the tetracationic cage [Pd 2 (L 2) 4 ][OTf] 4 (3) was found to encapsulate the anionic metal complex [PtCl 4 ] 2− through electrostatic interactions and also via hydrogen bonding with the amino groups of the bridging ligand displayed by this nanocage

N-Heterocyclic Carbene Coinage Metal Complexes Containing Naphthalimide Chromophore: Design, Structure, and Photophysical Properties

A series of novel N-heterocyclic carbene coinage metal complexes containing a naphthalimide (NI) chromophore has been prepared and fully characterized. Two types of molecules are described those where the NI unit is directly attached to the carbene unit with the general formulae [(L1)–M–X], M = Cu, X = Cl (1a); M = Ag, X = I (1b) and M = Au, X = Cl, (1c). While in the second family, a π-extended carbene ligand precursor L2–H+I− (3) was prepared where the NI unit is distant from the imidazole unit via a phenyl-alkyne bridge. Only two N-heterocyclic carbene metal complexes were prepared [(L2)–M–Cl], M = Cu (2a) and M = Au (2c). The related silver carbene compound could not be isolated. The molecular structure of the carbene complex 1c was determined and confirmed the formation of the target compound. Interestingly, the structure shows the presence of an aurophilic interaction Au···Au at 3.407 Å between two individual molecules. The photophysical properties of the compounds were investigated in solution at room temperature. Preliminary results suggested that all compounds are luminescent and act as blue emitters (420–451 nm). These transition emissions can be attributed to the intraligand origin of the NI chromphore. Moreover, the carbene complexes featuring L2 ligand with π-extended system were found to be more luminescent

Enantiopure Cyclometalated Rh(III) and Ir(III) Complexes Displaying Rigid Configuration at Metal Center: Design, Structures, Chiroptical Properties and Role of the Iodide Ligand

International audienceEnantiopure N-heterocyclic carbene half-sandwich metal complexes of the general formula [Cp*M(C^C:)I] (M = Rh, Ir; C^C: = NI-NHC; NI-H = Naphthalimide; NHC = N-heterocyclic carbene) are reported. The rhodium compound was obtained as a single isomer displaying six membered metallacycle and was resolved on chiral column chromatography to the corresponding enantiomers (S)-[Cp*Rh(C^C:)I] (S)-2 and (R)-[Cp*Rh(C^C:)I] (R)-2. The iridium congener, however, furnishes a pair of regioisomers, which were resolved into (S)-[Cp*Ir(C^C:)I] (S)-3 and (R)-[Cp*Ir(C^C:)I] (R)-3 and (S)-[Cp*Ir(C^C:)I] (S)-4 and (R)-[Cp*Ir(C^C:)I] (R)-4. These regioisomers differ from each other, only by the size of the metallacycle; five-membered for 3 and six-membered for 4. The molecular structures of (S)-2 and (S)-4 are reported. Moreover, the chiroptical properties of these compounds are presented and discussed. These compounds display exceptional stable configurations at the metal center in solution with enantiomerization barrier ΔG≠ up to 124 kJ/mol. This is because the nature of the naphthalimide-NHC clamp ligand and the iodide ligand contribute to their configuration’s robustness. In contrast to related complexes reported in the literature, which are often labile in solution

Selenoquinones Stabilized by Ruthenium( II) Arene Complexes: Synthesis, Structure, and Cytotoxicity

A new series of monoselenoquinone and diselenoquinone complexes, [((6)-p-cymene)Ru((4)-C6R4SeE)] (R=H, E=Se (6); R=CH3, E=Se (7); R=H, E=O (8)), as well as selenolate complexes [((6)-p-cymene)Ru((5)-C6H3R2Se)][SbF6] (R=H (9); R=CH3 (10)), stabilized by arene ruthenium moieties were prepared in good yields through nucleophilic substitution reactions from dichlorinated-arene and hydroxymonochlorinated-arene ruthenium complexes [((6)-p-cymene)Ru(C6R4XCl)][SbF6](2) (R=H, X=Cl (1); R=CH3, X=Cl (2); R=H, X=OH (3)) as well as the monochlorinated complexes [((6)-p-cymene)Ru((5)-C6H3R2Cl)][SbF6](2) (R=H (4); R=CH3 (5)). The X-ray crystallographic structures of two of the compounds, [((6)-p-cymene)Ru((4)-C6Me4Se2)] (7) and [((6)-p-cymene)Ru((4)-C6H4SeO)] (8), were determined. The structures confirm the identity of the target compounds and ascertain the coordination mode of these unprecedented ruthenium complexes of selenoquinones. Furthermore, these new compounds display relevant cytotoxic properties towards human ovarian cancer cells