"United we stand, divided we fall."--Aesop. Aggregation-induced emission (AIE) refers to a photophysical phenomenon shown by a group of luminogenic materials that are non-emissive when they are dissolved in good solvents as molecules but become highly luminescent when they are clustered in poor solvents or solid state as aggregates. In this Review we summarize the recent progresses made in the area of AIE research. We conduct mechanistic analyses of the AIE processes, unify the restriction of intramolecular motions (RIM) as the main cause for the AIE effects, and derive RIM-based molecular engineering strategies for the design of new AIE luminogens (AIEgens). Typical examples of the newly developed AIEgens and their high-tech applications as optoelectronic materials, chemical sensors and biomedical probes are presented and discussed.

Aggregation-Induced Emission: The Whole Is More Brilliant than the Parts

The preparation, structure, and chemistry of hypervalent iodine compounds are reviewed with emphasis on their synthetic application. Compounds of iodine possess reactivity similar to that of transition metals, but have the advantage of environmental sustainability and efficient utilization of natural resources. These compounds are widely used in organic synthesis as selective oxidants and environmentally friendly reagents. Synthetic uses of hypervalent iodine reagents in halogenation reactions, various oxidations, rearrangements, aminations, C–C bond-forming reactions, and transition metal-catalyzed reactions are summarized and discussed. Recent discovery of hypervalent catalytic systems and recyclable reagents, and the development of new enantioselective reactions using chiral hypervalent iodine compounds represent a particularly important achievement in the field of hypervalent iodine chemistry. One of the goals of this Review is to attract the attention of the scientific community as to the benefits of...

Advances in Synthetic Applications of Hypervalent Iodine Compounds

Light-Emitting Self-Assembled Materials Based on d(8) and d(10) Transition Metal Complexes.

Organophosphorus π-Conjugated Materials

Multimetallic catalysis based on heterometallic complexes and clusters.

Enhanced reactivity is shown by uncoordinated C≡C bonds in the proximity of a metal in phosphanylacetylene complexes. cis-[Pt(C6F5)2(thf)2] reacts with [M(C6F5)2(PPh2C≡CPh)2] (M=Pt, Pd) to form binuclear complexes containing the novel 2,3-bis(diphenylphosphanyl)-1,3-butadien-1-yl bridging ligand. Substitution of the solvent ligands with, for example, PPh2H (see picture) provides species that could be characterized by X-ray crystallography.

Double Insertion of Coordinated Phosphanylalkyne Ligands into a Pt−C6F5 Bond

A series of homoleptic and heteroleptic platinum(II) complexes [Pt(CCFc)2(L-L)] (L-L = COD 1, 1,1′-bis(diphenylphosphino)ferrocene (dppf) 2), Q2[cis/trans-Pt(C6F5)2(CCFc)2] (cis, Q = PMePh3, 3; trans, Q = NBu4, 4), (NBu4)[Pt(bzq)(CCFc)2] 5 (Hbzq = 7,8-benzoquinoline) and (NBu4)2[Pt(CCFc)4] 6 has been synthesized and characterized spectroscopically and the structures of 1·2CHCl3, 2 and 6·2H2O·2CH2Cl2 confirmed by single-crystal X-ray studies. The anion of complex 6, shows strong O–H⋯π(CC) interactions and weaker C–Cl⋯π(CC) contacts between the protons of two water and two CH2Cl2 molecules and the CαCβ of mutually cis alkynyl groups. In this complex the presence of additional O–H⋯H–C(Cp) and C–Cl⋯H–C(Cp) contacts gives rise to an extended bidimensional network. The optical and electrochemical properties of all derivatives have been examined. It is remarkable that for complexes 2 and 5 a facile oxidatively induced coupling, giving rise to 1,4-diferrocenylbutadiyne, is observed, this also having been proven by chemical oxidation.

Complexes of platinum(II) containing ferrocenylethynyl ligands: synthesis, characterization and spectroscopic and electrochemical properties

https://www.rsc.org/suppdata/CC/b7/b706439j/b706439j.pdf

Unusual luminescent octanuclear stellate platinacycle self-assembled by Pt-Ag bonds.

The reaction between (NBu(4))[Pt(bzq)(C(6)F(5))(2)] (1, bzq = 7,8-benzoquinolate) and AgClO(4) in a 1 : 1 molar ratio, in acetone, gives the polymer [{Pt(bzq)(C(6)F(5))(2)}Ag](n) (2). The reaction of 2 with equimolecular amounts of PPh(3) and SC(4)H(8) (tht) produces the bimetallic complexes [{Pt(bzq)(C(6)F(5))(2)}AgL] (L = PPh(3) (3), tht (4)). For L = py, decomposition takes place and [Pt(bzq)(C(6)F(5))py] (5) is obtained. All these complexes have been characterized by X-ray diffraction. The most interesting features of complexes 2-4 is the presence of Pt-Ag bonds, with Pt-Ag distances of ca. 2.75 A. Besides, the silver centres establish short η(1) bonding interactions with the C(ipso) of the bzq ligands, with distances Ag-C of ca. 2.45 A. Complex 2 is a one-dimensional infinite chain in which the fragments "Pt(bzq)(C(6)F(5))(2)(-)" and Ag(+) alternate. On the other hand, complexes 1 and 3-5 show intermolecular pairing through π···π interactions between the aromatic rings of the bzq ligand, having interplanar separations of ca. 3.5 A. Complex 2 dissolves in donor solvents (acetone, THF) as discrete bimetallic solvated fragments [{Pt(bzq)(C(6)F(5))(2)}AgS(n)] (S = solvent), similar to complexes 3 and 4. The persistence of the Pt-Ag bond in 2-4, supported by multinuclear NMR spectroscopy, causes a significant blue-shift in the lowest-lying absorption in relation to 1. This fact is attributed (TD-DFT) to a remarkable modification of the orbitals contributing to the HOMO, which changes the character of the transition from (1)LC/(1)MLCT in 1 to admixture (1)L'LCT/(1)MLCT in the bimetallic complexes. The low energy feature (490-530 nm) of 2 in solid state is attributed to CT from the Pt fragments to the Ag centers. Complexes 2-4 are only emissive in rigid media (solid and glasses). In the solid state, the metallic chain 2 exhibits a bright orange emission (560 nm, 298 K; 590 nm, 77 K), assigned to an excited state involving charge transfer from the platinum fragment with a remarkable contribution of C(6)F(5) (Ar(f)) rings to the Pt-Ag bond ((3)LMM'CT/(3)L'M'CT). However, 3 and 4 exhibit in solid state at 298 K a vibronic band, which is clearly resolved in two close non-equilibrated bands at 77 K in 3, tentatively ascribed to a mixture of (3)MLCT/(3)L'LCT transitions modified by the formation of the Pt-Ag bond. In glassy solution (77 K) 2-4 display a vibronic emission ascribed primarily to (3)LC character.

M. Teresa Moreno

Papers

Double Insertion of Coordinated Phosphanylalkyne Ligands into a Pt−C6F5 Bond

Complexes of platinum(II) containing ferrocenylethynyl ligands: synthesis, characterization and spectroscopic and electrochemical properties

Unusual luminescent octanuclear stellate platinacycle self-assembled by Pt-Ag bonds.

Benzoquinolateplatinum(II) complexes as building blocks in the synthesis of Pt–Ag extended structures

Synthesis and Structure of New Neutral Bimetallic Platinum Hydride Complexes