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1.
Adv Sci (Weinh) ; 11(18): e2307448, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38447160

RESUMO

The synthesis of a family of chiral and enantiomerically pure pyridyl-diamide (pda) ligands that upon complexation with europium [Eu(CF3SO3)3] result in chiral complexes with metal centered luminescence is reported; the sets of enantiomers giving rise to both circular dichroism (CD) and circularly polarized luminescence (CPL) signatures. The solid-state structures of these chiral metallosupramolecular systems are determined using X-ray diffraction showing that the ligand chirality is transferred from solution to the solid state. This optically favorable helical packing arrangement is confirmed by recording the CPL spectra from the crystalline assembly by using steady state and enantioselective differential chiral contrast (EDCC) CPL Laser Scanning Confocal Microscopy (CPL-LSCM) where the two enantiomers can be clearly distinguished.

2.
Chem Commun (Camb) ; 52(14): 2940-3, 2016 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-26779581

RESUMO

Langmuir-Blodgett (LB) and drop-cast (DC) films prepared from [Ru(1)3][PF6]2 and Co4POM (1= 4,4'-bis((n)nonyl)-2,2'-bipyridine, Co4POM = K10[Co4(H2O)2(α-PW9O34)2]) have been evaluated as water oxidation catalysts and their electrocatalytic performances are reported; DC films evolve more O2 per unit area than LB films and the catalyst is stable on an FTO surface for ≈500-600 minutes.


Assuntos
Água/química , Catálise , Eletroquímica , Oxirredução
3.
Dalton Trans ; 44(16): 7626-33, 2015 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-25812017

RESUMO

The first examples of [Cu(N^N)(POP)](+) complexes (POP = bis(2-(diphenylphosphino)phenyl)ether) in which the N^N domain is a 2,2':6',2''-terpyridine (tpy) ligand have been prepared and characterized; N^N = tpy, 5,5''-dimethyl-2,2':6',2''-terpyridine (1), 4'-(4-tolyl)-2,2':6',2''-terpyridine (2), 4'-(4-npropoxyphenyl)-2,2':6',2''-terpyridine (3) and 4'-(4-nbutoxyphenyl)-2,2':6',2''-terpyridine (4). In solution, the tpy domain in each [Cu(N^N)(POP)][PF6] complex is C2-symmetric, consistent with either tridentate coordination or a low energy dynamic process involving bidentate ligands; for [Cu(2)(POP)][PF6] and [Cu(4)(POP)][PF6], the (1)H NMR spectra showed negligible change between 295 and 210 K. The single crystal structures of [Cu(tpy)(POP)][PF6] and [Cu(4)(POP)][PF6] are presented. The asymmetric unit of [Cu(tpy)(POP)][PF6] contains two independent cations; in one the tpy ligand is tridentate and in the other, it is bidentate with the non-coordinated pyridine ring facing the Cu atom (Cu···N = 3.146(1) Å). In contrast, the solid-state structure of [Cu(4)(POP)][PF6] features a [Cu(4)(POP)](+) cation containing a bidentate tpy-domain with the non-coordinated pyridine ring oriented with the N-atom facing away from the Cu atom; this conformation may be associated with inter-cation NHC non-classical hydrogen bonds. The photophysical properties of [Cu(N^N)(POP)][PF6] with N^N = tpy or 1­4 are described. In the solid state at room temperature, the compounds are poorly emissive. In solution, the emission behaviour is consistent with ligand dissociation. This is supported by (1)H and (31)P NMR spectroscopic data which show POP and [Cu(POP)2](+) in solutions of aged samples; mass spectrometric data are consistent with the formation of [Cu(N^N)2](2+) in these samples.

4.
Dalton Trans ; 42(14): 4970-7, 2013 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-23389257

RESUMO

We report the synthesis of copper(I) complexes of three ligands which contain a potential P,N,N,P-metal binding site. Elemental analysis confirms that the bulk products possess a composition of [CuL][PF6] where L = 1, 2 or 3. Electrospray mass spectrometry (ESI MS) provides evidence for speciation in MeCN or MeOH solutions and the formation of both [CuL]+ and [Cu2L2]2+; addition of NaCl to the ESI MS samples aids the observation of dinuclear species as [Cu2L2Cl]+ ions. NMR spectroscopic data for a CD3CN solution of [Cu(1)][PF6] were consistent with a mononuclear species, but more complex multinuclear spectra were observed for the same compound dissolved in CD2Cl2. In the solid state, dimeric species dominate. Crystals grown from CH2Cl2 solutions of [Cu(1)][PF6] are found to be [Cu2(1)2][PF6]2·6CH2Cl2; each Cu+ ion in the centrosymmetric cation is bound in an N,O,P,P-coordination sphere, the N-donor originating from the pyridine ring. In [Cu2(3)2][PF6]2, each bridging ligand in the centrosymmetric [Cu2(3)2]2+ ion acts as a P,N-chelate to each Cu+ ion. Competing with this dimeric assembly is that of a circular helicate in which each ligand 3 bridges adjacent pairs of copper(I) ions in a chiral, hexameric complex; both the Δ,Δ,Δ,Δ,Δ,Δ- and Λ,Λ,Λ,Λ,Λ,Λ-enantiomers are present in the crystal lattice; in [Cu6(3)6]6+, each ligand coordinates as a bis(P,N-chelate). The solution absorption spectra of [Cu(1)][PF6], [Cu(2)][PF6] and [Cu(3)][PF6] are dominated by ligand-based transitions and none of the copper(I) complexes exhibits emissive behaviour in solution.

5.
Chem Commun (Camb) ; (33): 4959-61, 2009 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-19668815

RESUMO

The formation of a self-assembly between a sensitising antenna and an Eu(III) functionalised cyclen complex 1.Eu, tethered to a gold surface via a C(12) alkyl thiol spacer, is described where changes in the Eu(III) emission signal the formation, and dissociation, of a ternary complex.

6.
Org Lett ; 6(10): 1557-60, 2004 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-15128235

RESUMO

Colorimetric azobenzene based chemosensors 1 and 2 were designed for detection of transition-metal ions such as Cu(II) under physiological pH conditions. The internal charge transfer (ICT) sensors are highly colored, absorbing in the green. For 1, the Cu(II) recognition gives rise to red-to-yellow color changes that are visible to the naked-eye and reversible upon addition of EDTA, whereas for 2, which lacks the aromatic o-methoxy chelating group, no such changes were observed.

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