"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.

Neutral pentafluorophenyl benzoquinolinyl Pt II
 [Pt(bzq)(HC^N−κN)(C 6
 F 5
 )] (1 a–g) complexes, bearing nonmetalated N-heterocyclic HC^N ligands [HC^N=2,5-diphenyl-1,3,4-oxadiazole (Hoxd) a, 2-(2,4-difluorophenyl)pyridine (dfppy) b, 2-phenylbenzo[d]thiazole (pbt) c, 2-(4-bromophenyl)benzo[d]thiazole (Br-pbt) d, 2-phenylquinoline (pq) e, 2-thienylpyridine (thpy) f, 1-(2-pyridyl)pyrene (pypy) g], and heteroleptic bis(cyclometalated) Pt IV
 fac-[Pt(bzq)(C^N)(C 6
 F 5
 )Cl] (2 b–g, bzq: benzo[h]quinolinyl) derivatives, generated by oxidation of 1 b–g with PhICl 2
 , are reported. The oxidation reaction of 1 a evolved with formation of the bimetallic Pt IV
 complex syn-[Pt(bzq)(C 6
 F 5
 )Cl(μ-OH)] 2
 3. The crystal structures of 1 a,d,f, 2 b,d,e and 3 were corroborated by X-ray crystallography. A comparative study of the absorption and photoluminescence properties of the two series of complexes Pt II
 (1) and Pt IV
 (2), supported by time-dependent DFT calculations (TD-DFT), is presented. The low-lying transitions (absorption and emission) of Pt II
 complexes 1 a–e [solution and polystyrene (PS) films] were assigned to the IL/MLCT mixture located on the cyclometalated Pt(bzq) unit, with minor IL′/ML′CT/LL′CT contributions involving the non-metalated ligand. Complex 1 g, bearing the more delocalized pyridyl pyrene (Hpypy) as an ancillary ligand, shows dual 1
 ππ* and 3
 ππ* (Hpypy) emission in fluid CH 2
 Cl 2
 and dual 3
 IL/ 3
 MLCT [Pt(bzq)] and [ 3
 ππ*, Hpypy] phosphorescence at 77 K. Upon oxidation, Pt IV
 complexes 2 b–f display (solution, PS) ligand-based phosphorescence that arises from the bzq in 2 b ( 3
 LC) or from the second C^N ligand in 2 c–f ( 3
 L′C) with some 3
 LL′CT in 2 f. Despite metalation of the pyrenyl group, 2 g exhibits dual emission 1
 ππ*/ 3
 ππ* located on the pypy chromophore.

Design of Luminescent, Heteroleptic, Cyclometalated PtII and PtIV Complexes: Photophysics and Effects of the Cyclometalated Ligands.

A series of mononuclear platinum complexes containing diynyldiphenylphosphine ligands [cis-Pt(C6F5)2(PPh2CCC6H4CCR)L]n
				(n
				= 0, L = tht, R = Ph 2a, But2b; L = PPh2CCC6H4CCR, 4a, 4b; n
				=
				−1, L = CN−, 3a, 3b) has been synthesized and the X-ray crystal structures of 4a and 4b have been determined. In order to compare the η2-bonding capability of the inner and outer alkyne units, the reactivity of 2–4 towards [cis-Pt(C6F5)2(thf)2] or [Pt(η2-C2H4)(PPh3)2] has been examined. Complexes 2 coordinate the fragment “cis-Pt(C6F5)2” using the inner alkynyl fragment and the sulfur of the tht ligand giving rise the binuclear derivatives [(C6F5)2Pt(µ-tht)(µ-1κP:2η2-Cα,Cβ-PPh2CCC6H4CCR)Pt(C6F5)2]
				(R = Ph 5a, But5b). The phenyldiynylphosphine complexes 2a, 3a and 4a react with [Pt(η2-C2H4)(PPh3)2] to give the mixed-valence Pt(II)–Pt(0) complexes [{(C6F5)2LPt(µ-1κP:2η2-C5,C6-PPh2CCC6H4CCPh)}Pt(PPh3)2]n
				(L = tht 6a, CN 8a and PPh2CCC6H4CCPh 9a) in which the Pt(0) fragment is η2-complexed by the outer fragment. Complex 6a isomerizes in solution to a final complex [{(C6F5)2(tht)Pt(µ-1κP:2η2-Cα,Cβ-PPh2CCC6H4CCPh)}Pt(PPh3)2]
				7a having the Pt(0) fragment coordinated to the inner alkyne function. In contrast, the tert-butyldiynylphosphine complexes 2b and 3b coordinate the Pt(0) unit through the phosphorus substituted inner acetylenic entity yielding 7b and 8b. By using 4a and 2 equiv. of [Pt(η2-C2H4)(PPh3)2] as precursors, the synthesis of the trinuclear complex [cis-{(C6F5)2Pt(µ-1κP:2η2-C5,C6-PPh2CCC6H4CCPh)2}(Pt(PPh3)2)2]
				10a, bearing two Pt(0)(PPh3)2
				η2-coordinated to the outer alkyne functions is achieved. The structure of 7a has been confirmed by single-crystal X-ray diffraction.

Synthesis and characterization of mono- and binuclear platinum complexes containing terminal and bridging diynyldiphenylphosphine ligands

The reaction between [{PtAg2(C6F5)2(CCR)2}n] and triphenylphosphine in a molar ratio of 1 : 2 has resulted in a good yield of the trinuclear mixed-metal complexes [PtAg2(C6F5)2(µ-η2,σ-CCR)(µ3-σ-CCR)(PPh3)2](R = Ph 3 or But4), and the crystal structure of 3 revealed that they contain two different types of unsymmetrical µ3-σ and µ-η2, σ-edge-bridging alkynyl ligands.

Dalton communications. Neutral PtAg2 clusters containing unsymmetrical µ3-σ and µ-η2,σ alkynyl groups. Crystal structure of [PtAg2(C6F5)2(µ-η2,σ-CCPh)(µ3-σ-CCPh)(PPh3)2]·0.25CH2Cl2

Contrasting Thermal and Photochemical Intramolecular Coupling in Alkynylphosphine Platinum(II) Complexes

Treatment of the polymeric derivatives [{PtAg2(C6F5)2(CCR)2}n](R = Ph or But) with 2 molar equivalents of neutral ligands L (Ag:L 1:1) afforded the new more soluble trinuclear mixed-ligand complexes [PtAg2(C6F5)2(CCR)2L2]1–8(L = PPh3, PEt3, CNBut or C5H5N). Analogous reactions with 1 molar equivalent of L (Ag:L 2:1) produced, however, only a partial depolymerization of [{PtAg2(C6F5)2(CCR)2}n] to give the hexanuclear complexes [Pt2Ag4(C6F5)4(CCR)4L2]9–16. Compounds 9–12 have also been obtained by treatment of the binuclear derivatives [NBu4][Pt(C6F5)2(µ-CCR)2AgL] with AgClO4(1:1 molar ratio) in acetone. Similar reactions of [{PtAg2(C6F5)2(CCR)2}n] with 1 or 0.5 equivalent of 1,2-bis(diphenylphosphino)ethane (dppe) yielded insoluble complexes of composition [{PtAg2(C6F5)2(CCR)2(dppe)}n]17, 18 or [{Pt2Ag4(C6F5)4(CCR)4(dppe)}n]19, 20 which are thought to be polymeric. The crystal structure of [Pt2Ag4(C6F5)4(µ3-η2-CCPh)4(PPh3)2]·0.5CH2Cl29·0.5CH2Cl2 has been determined by X-ray diffraction methods.

Novel heterotrinuclear, PtAg2, and hexanuclear, Pt2Ag4, compounds containing bridging alkynyl groups. Crystal structure of [Pt2Ag4(C6F5)4(µ3-η2-CCPh)4(PPh3)2]·0.5CH2Cl2

M. Teresa Moreno

Papers

Design of Luminescent, Heteroleptic, Cyclometalated PtII and PtIV Complexes: Photophysics and Effects of the Cyclometalated Ligands.

Synthesis and characterization of mono- and binuclear platinum complexes containing terminal and bridging diynyldiphenylphosphine ligands

Dalton communications. Neutral PtAg2 clusters containing unsymmetrical µ3-σ and µ-η2,σ alkynyl groups. Crystal structure of [PtAg2(C6F5)2(µ-η2,σ-CCPh)(µ3-σ-CCPh)(PPh3)2]·0.25CH2Cl2

Contrasting Thermal and Photochemical Intramolecular Coupling in Alkynylphosphine Platinum(II) Complexes

Novel heterotrinuclear, PtAg2, and hexanuclear, Pt2Ag4, compounds containing bridging alkynyl groups. Crystal structure of [Pt2Ag4(C6F5)4(µ3-η2-CCPh)4(PPh3)2]·0.5CH2Cl2