Monoanionic dipyrrin-pyridine ligands: Synthesis, structure and photophysical properties

A novel monoanionic tetradentate N4 ligand (F5DPPy) based on a dipyrromethene skeleton as a molecular platform and decorated with pyridine rings at the 1- and 9-positions of the dipyrrin motif has been prepared and characterized. Interestingly, although this ligand is weakly fluorescent, it presents a chelation-enhanced fluorescence effect of around 150 times upon coordination to ZnII. Time-dependent (TD) DFT calculations reproduce nicely the spectroscopic features of both the ligand and the complex, and analysis of the electron density redistribution in the excited state suggests that a better orbital overlap of the HOMO and LUMO in F5DPPyZnCl compared with F5DPPy is responsible for the more intense transitions observed with the former system. As such, this ligand opens interesting perspectives in the design of ratiometric sensors

Ambiphilic Diphosphine–Borane Ligands: Metal→Borane Interactions within Isoelectronic Complexes of Rhodium, Platinum and Palladium.

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Original transition metal→indium interactions upon coordination of a triphosphine-indane

cited By 42International audienceThe triphosphine-indane TPI ([o-i-Pr2P(C6H 4)]3In) has been prepared and found to react with [Pd(P-t-Bu3)2] and [AuCl(SMe2)]. According to X-ray diffraction analyses and DFT calculations, the ensuing complexes both display original donor-acceptor M→In interactions, although of markedly different nature and magnitude. © 2011 American Chemical Society

Copper(I) complexes derived from mono- and diphosphino-boranes: Cu→b interactions supported by arene coordination

cited By 66International audienceThe monophosphino-boranes o-iPr2P(C6H 4)BR2 (1: R = Ph and 3: R = Cy) and diphosphino-boranes [o-R2P(C6H4)]2BPh (5: R = Ph and 6: R = iPr) readily react with CuCl to afford the corresponding complexes [o-iPr2P(C6H4)BPh2]Cu(μ-Cl) 2 2, [o-iPr2P(C6H4)BCy 2]Cu(μ-Cl)2 4, [o-Ph2P(C6H 4)]2BPhCuCl 7, and [o-iPr2P(C 6H4)]2BPhCuCl 8. The presence of Cu→B interactions supported by arene coordination within complexes 2, 7, and 8 has been unambiguously evidenced by NMR spectroscopy and X-ray diffraction studies. The unique η2-BC coordination mode adopted by complexes 7 and 8 has been thoroughly analyzed by density-functional theory (DFT) calculations. © 2009 American Chemical Society

Gold→Silane and Gold→Stannane Complexes: Coordination of Saturated Molecules as Acceptor Ligands

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Dissection of light-induced charge accumulation at a highly active iron porphyrin: insights in the photocatalytic CO2_2 reduction

International audienceIron porphyrins are among the best molecular catalysts for the electrocatalytic CO$_2$ reduction reaction. Powering these catalysts with the help of photosensitizers comes along with a couple of unsolved challenges that need to be addressed with much vigor. We have designed an iron porphyrin catalyst decorated with urea functions (UrFe) acting as a multipoint hydrogen bonding scaffold towards the CO$_2$ substrate. We found a spectacular photocatalytic activity reaching unreported TONs and TOFs as high as 7270 and 3720 h$^{-1}$ , respectively. While the Fe$^0$ redox state has been widely accepted as the catalytically active species, we show here that the Fe(I) species is already involved in the CO$_2$ activation, which represents the rate-determining step in the photocatalytic cycle. The urea functions help to dock the CO$_2$ upon photocatalysis. DFT calculations bring support to our experimental findings that constitute a new paradigm in the catalytic reduction of CO$_2

Group 10 and 11 metal boratranes (Ni, Pd, Pt, CuCl, AgCl, AuCl, and Au +) derived from a triphosphine-borane

cited By 128International audienceThe ambiphilic triphosphine-borane ligand 1 TPB = [o-iPr 2P-(C6H4)]3B readily coordinates to all group 10 and 11 metals to afford a complete series of metal boratranes (TPB)[M] 2-8 (2: M = Ni, 3: M = Pd, 4: M = Pt, 5: M = CuCl, 6: M = AgCl, 7: M = AuCl, 8: M = Au+). Spectroscopic and structural characterization unambiguously establishes the presence of M→B interactions in all of these complexes. The first evidence for borane coordination to copper and silver is provided, and the Au→B interaction is shown to persist upon chloride abstraction. Experimental and theoretical considerations indicate that the M→B interaction is strongest in the Pt and Au complexes. The influence of the oxidation state and charge of the metal is substantiated, and the consequences of relativistic effects are discussed. The coordination of the σ-acceptor borane ligand is found to induce a significant bathochromic shift of the UV-vis spectra, the Ni, Pd, and Pt complex presenting strong absorptions in the visible range. In addition, all of the group 10 and 11 metal boratranes adopt C3 symmetry both in the solid state and in solution. The central M→B interaction is found to moderately influence the degree of helicity and configurational stability of these three-bladed propellers, and DFT calculations support a dissociative pathway for the inversion process. © 2008 American Chemical Society