The metallocene cation complex [Cp*2ZrCH3](+)[B(C6F5)4](-) inserts the phosphino-substituted alkyne Ph-C≡C-PPh2 into the [Zr]-CH3 bond to form the internally phosphane-stabilized cation [Cp*2Zr-C(═CMePh)PPh2](+) (10). Complex 10 adds alkyl isocyanides as well as pivalonitrile at a lateral site at the bent metallocene wedge with retention of the Zr-P bond. Complex 10 acts as a reactive frustrated Lewis pair toward heterocumulenes, undergoing Zr(+)/P addition reactions to the carbonyl groups of an alkyl isocyanate and of carbon dioxide to form the respective five-membered metallaheterocyclic adducts 13 and 14. With mesityl azide complex 10 undergoes a Zr(+)/P FLP N,N-addition reaction at the terminal azide nitrogen atom to form the four-membered FLP cycloadduct 15. The Zr(+)/P FLP is a reactive hydrogen activator. In a stoichiometric reaction it generates a hydridozirconocene cation that subsequently serves as a hydrogenation catalyst for various olefinic or acetylenic substrates. The Zr(+)/P pair 10 undergoes selective 1,4-addition reactions to conjugated enones and to a conjugated ynone to give the corresponding seven-membered metallacyclic Zr(+)/P FLP addition products. Many compounds of this study were characterized by X-ray diffraction.

of pristine halide double perovskites limits their applications in the field of light-emitting diodes (LEDs).One prevailing strategy to improve the optical properties of halide double perovskites is chemical substitution. [5] For instances, alloying Na + into Cs 2 Ag-InCl 6 single crystals can break the parityforbidden transition of dark self-trapped excitons (STEs), leading to an increase in photoluminescence quantum yield by three orders of magnitude. [1a] Incorporation of Mn 2+ into Cs 2 AgInCl 6 nanocrystals can generate effective energy transfer channels from STEs to Mn 2+ ions, resulting in bright orange emission with enhanced quantum yield of 16%. [3] In addition, intense emission in the near-red region can be achieved by doping Yb 3+ into Cs 2 AgBiBr 6 bulk perovskites. [6] However, as shown above, chemical substitution generally leads to emission in the yellow to red spectral region. To the best of our knowledge, there are very limited reports on blue emissive halide double perovskites, [4] in particular for pristine ones. Consequently, it's significant to explore blue emitting halide double perovskites for the development of blue and white perovskite LEDs.Herein, we report an air-stable, strong blue-emitting allinorganic rare-earth double perovskite with a chemical formula of Cs 2 NaScCl 6 . In contrast to the weak emission of previously reported pristine double perovskites, Cs 2 NaScCl 6 exhibits intense blue emission peaking at 445 nm with an averaged photoluminescence quantum yield (PLQY) of 29.05%. In addition, Mn 2+ ions can be efficiently incorporated into the lattice of Cs 2 NaScCl 6 single crystals, resulting in unusual tunable dual broadband emission with a blue band peaking at 450 nm and a red band centered at 635nm. Detailed spectral characterizations were performed to unveil the underlying emission mechanism. The blue emission is ascribed to the radiative recombination of STEs in the host, and the additional red emission is assigned to the transitions of isolated Mn 2+ ions and magnetic coupled Mn 2+ -Mn 2+ pairs. Results and DiscussionCs 2 NaScCl 6 single crystals were obtained from concentrated hydrochloric acid via a cooling induced crystallization method. The crystal structure was determined through single-crystal X-ray diffraction (SCXRD) analysis. As shown in Figure 1a, the Cs + group is surrounded by a network of alternating, Halide double perovskites have been regarded as promising alternatives to famous lead halide perovskites in the field of luminescent materials. However, the low-emission efficiency of pristine ones and the lack of efficient blue emitters remain considerable obstacles for their applications in light-emitting devices. Here, an air-stable, all-inorganic Sc-based double perovskite Cs 2 NaScCl 6 is reported, which exhibits strong blue emission peaking at 445 nm with an averaged quantum yield of 29.05% (the highest reported value for pristine halide double perovskites). The rare-earth double perovskite also shows excellent stability against heat and irradiation. Bul...

Treatment of the metallocene cation complexes [Cp*2MCH3](+)[B(C6F5)4](-) (M = Zr or Hf) with trimethylsilyl(diarylphosphino)acetylenes Ar2P-C≡C-SiMe3 (Ar = Ph or p-tolyl) resulted in the formation of internal phosphane stabilized cations [Cp*2M-C(CH3)═C(SiMe3)PAr2](+) 4 through the unique 1,1-carbometalation reaction under mild conditions. In contrast, when the low Lewis basicity phosphane containing alkyne (C6F5)2P-C≡C-SiMe3 was used, normal 1,2-carbometalation occurred to produce complexes 5, which show agostic coordination of a Me-Si group to the metal center. Complex 4a reacts with n-butyl isocyanide to give the coordination product 6, which has the Zr-P bond retained. Treatment of 4a with N2O gave the five-membered metallaheterocycle 7 by oxidation of the phosphane. The vicinal M(+)/P complexes 4 also show some typical FLP reactivity. They add to cinnamaldehyde or paraformaldehyde, for example, to produce carbonyl addition products 8 and 9, respectively. Complex 4a adds to the N═O functionality of nitrosobenzene with formation of 10. The vicinal M(+)/P systems 4 behave as reactive frustrated Lewis pairs toward hetercumulenes, undergoing 1,2-addition to the C═O bond of CO2 and the S═O bond of SO2 to form the respective adducts 11 and 12. The Zr(+)/P FLP 4a reacts with PhN═S═O to give the addition product 13, in which the phosphane Lewis base has added to the nitrogen atom and the Zr(+) Lewis acid to both atoms of the S═O unit. The reaction of complex 4a with the metal complex [Ir(COD)Cl]2 affords a heterobimetallic Zr/Ir product 14. The vicinal M(+)/P complexes 4 can be also used as efficient catalysts for the regioselective dimerization of phenyl acetylene.

Multipolar second-order nonlinear optical (NLO) materials have become a topic of intense interest owing to the finding that donor-acceptor-substituted molecules with threefold rotational symmetry (octupolar chromophores) can have an improved transparency/optical nonlinearity tradeoff when compared with traditional dipolar chromophores.[1] While octupolar nonlinearity has been achieved at the molecular level, [2, 3] its demonstration in multidimensional crystalline systems remains challenging. [3][4][5] Studies on the assembly of metal-organic frameworks (MOFs) from molecular building blocks, on the other hand, have uncovered methods to build extended structures with novel topologies and exploitable functions. [4][5][6][7] In principle, octupoles can be expressed in cubic, tetrahedral, and trigonal symmetries.[3] Trigonal molecules or bridging ligands are thus very useful building blocks for the construction of higher-dimensional octupolar NLO-active MOF materials, but the products normally do not adopt acentric trigonal structures or have weak NLO responses. [7] We recently prepared serendipitously an organically templated 3D octupolar MOF exhibiting very strong and cation-dependent second harmonic generation (SHG) responses.[5c] We have now developed a strategy for the rational synthesis of 3D octupolar materials by carrying over both threefold symmetry and chirality of organic bridging ligands into MOFs through coordination assembly. To this end, we synthesized rigid trigonal tris(4-pyridylduryl)borane (L) featuring a three-coordinate boron chromophore.[8] The tridurylborane core adopts a propellerlike conformation to minimize repulsive interactions between its phenyl rings, and therefore it is helically chiral (D and L isomers) with D 3 octupolar symmetry as shown in Scheme 1. The vacant and low-lying 2p p orbital on the boron center makes threecoordinate organoboron derivatives good electron acceptors that have versatile potential applications in organic lightemitting diodes and nonlinear optics.[8] Herein we present the assembly of chiral octupolar metal-organoboron frameworks with exceptional (14,3) topology [9] which display significant and, more interestingly, anion-tunable SHG responses.Racemic L was synthesized in 70 % yield by Suzuki coupling between 4-pyridylboronic acid and tris(iododuryl)-borane, which was obtained in four steps in good overall yield from readily available 1,2,4,5-tetramethylbenzene (Scheme 1). Ligand L was characterized by 1 H and 13 C NMR spectroscopy and ESI mass spectrometry. Single crystals of eight compounds with the general formula [MX 2 L]·G [M = Cd, X = Cl, Br, I, NO 3 , OAc, ClO 4 (1 a-1 f), MX 2 = CuCl 2 (2), CoCl 2 (3); G = 2 H 2 O for 1 and 2 and 3/ 2 CH 3 OH·H 2 O for 3] were readily obtained in good yields by heating a mixture of MX 2 ·n H 2 O and L in dimethylsulfoxide

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