Highly effective binding of neutral dinitriles by simple alkyl-substituted pillar[5]arenes and the formation of interpenetrated geometries are reported. The resulting host-guest complexes represent one of the most efficient recognition motifs based on pillararenes.

The displacement of CO in a few simple Fe(I)-Fe(I) hydrogenase model complexes by bisphosphine ligands Ph2P-(CH2)n-PPh2 [with n = 1 (dppm) or n = 2 (dppe)] is described. The reaction of [{mu-(SCH2)2CH2}Fe2(CO)6] (1) and [{mu-(SCH2)2N(CH2CH2CH3)}Fe2(CO)6] (2) with dppe gave double butterfly complexes [{mu-(SCH2)2CH2}Fe2(CO)5(Ph2PCH2)]2 (3) and [{mu-(SCH2)2N(CH2CH2CH3)}Fe2(CO)5(Ph2PCH2)]2 (4), where two Fe2S2 units are linked by the bisphosphine. In addition, an unexpected byproduct, [{mu-(SCH2)2N(CH2CH2CH3)}Fe2(CO)5{Ph2PCH2CH2(Ph2PS)}] (5), was isolated when 2 was used as a substrate, where only one phosphorus atom of dppe is coordinated, while the other has been converted to P=S, presumably by nucleophilic attack on bridging sulfur. By contrast, the reaction of 1 and 2 with dppm under mild conditions gave only complexes [{mu-(SCH2)2CH2}Fe2(CO)5(Ph2PCH2PPh2)] (6) and [{mu-(SCH2)2N(CH2CH2CH3)}Fe2(CO)5(Ph2PCH2PPh2)] (8), where one ligand coordinated in a monodentate fashion to one Fe2S2 unit. Furthermore, under forcing conditions, the complexes [{mu-(SCH2)2CH2}Fe2(CO)4{mu-(Ph2P)2CH2}] (7) and [{mu-(SCH2)2N(CH2CH2CH3)}Fe2(CO)4{mu-(Ph2P)2CH2}] (9) were formed, where the phosphine acts as a bidentate ligand, binding to both the iron atoms in the same molecular unit. Electrochemical studies show that the complexes 3, 4, and 9 catalyze the reduction of protons to molecular hydrogen, with 4 electrolyzed already at -1.40 V versus Ag/AgNO3 (-1.0 V vs NHE).

The construction of metal±organic framework (MOF) coordination polymers is currently receiving considerable attention owing to their potential properties as functional solid materials, as well as their fascinating framework structures. [1±3] Particularly widely explored have been MOFs with porous chiral structures in which chiral ligands, chiral templates, or chiral functionalization of achiral zeolites are used to perform enantioselective separations and syntheses. [4±7] It is challenging to prepare chiral MOF materials with known chiral topology from an achiral building unit.Learning from nature©s minerals, and utilizing the welldefined coordination geometries of metal centers, some structures of minerals with specific functionality, such as perovsktie, [8] rutile, [9] PtS, [10] and feldspar [11] have been artificially produced by replacing monoatomic anions (O 2À , S 2À ) with polyatomic organic m ligands. The quartz phase, which is chiral, has unique piezoelectricity and thermally sensitive properties and is widely used in resonators and sensors. [12] Although the SiO 2 phase with quartz topology is thermodynamically more stable than cristobalite which has diamond topology, in nature or in artificial materials, known phases which have quartz topology are rare with only one example, a cyano-bridged coordination polymer, reported by Robson and co-workers. [13] Generally, most materials comprising fourconnected tetrahedral (T) units, including MOFs, exist in the diamond topology, [1c,d, 14] rather than the quartz topology, while SiO 2 and GeO 2 are minerals that have both a quartz polymorph and cristobalite with diamond topology. Interestingly, when cristobalite is quenched to room temperature, [15] it is transformed reconstructively to the quartz polymorph.Herein we report the preparation of two quartzlike, chiral, open MOFs, Zn(ISN) 2 ¥2 H 2 O (ISN ¼ isonicotinate), assigned QMOF-1, with the low symmetry of a-quartz and InH(BDC) 2 (BDC ¼ terephthalate), QMOF-2, with the high symmetry of b-quartz. QMOF-1 with a large (~8.6 ä) left-handed channel was successfully synthesized with an asymmetric ISN ligand by using a low-temperature diffusion method (room temperature) similar to the preparation of metal carboxylate [17] . On using a highly distorted complex anion [In(O 2 CR) 4 ] À as the T block, [16] and terephthalate as a linear rod, we could assemble the anion-type b-quartzlike network QMOF-2 with a right-handed channel (~7.8 ä).

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Doped nanoparticles (especially bimetal doped nanoparticles) have attracted extensive interest not only for fundamental scientific research but also for application purposes. However, their indefinite composition (structure) and broad distribution hinder an insightful understanding of the interaction between these invasive metals in bimetal doped nanoparticles. Fortunately, atom-precise bimetal doped ultrasmall nanoparticles (nanoclusters) provide opportunities to obtain such insights. However, atom-precise trimetal nanoclusters and their structures have rarely been reported. Here, we successfully dope thiolated Au 25 nanoclusters with Hg and Ag successively by using a biantigalvanic reduction method. We then fully characterize the as-obtained trimetal nanoclusters using multiple techniques (including single-crystal X-ray crystallography), and we demonstrate that the mercury and silver dopings exhibit not only a synergistic but also a counteractive influence on some of the physicochemical properties of Au 25 .

Water-soluble DNA cross-linking phenol and biphenol derivatives 3 and 6 have been synthesized by a Mannich reaction. Both of them can cross-link DNA by photoactivation using visible light (wavelength > 400 nm). Compound 6 can cross-link DNA at pH 5.0 and 7.7, whereas no cross-link was observed at pH 10.0. Density functional theory (DFT) calculation indicated that 6 displays a twist structure. Therefore, it could bind to DNA naturally and has potent property to cross-link DNA after photoactivation.

A series of neutral nickel complexes [Ni(Ph)(PPh3)(N, O)] with Schiff-base ligands (N, O) [N, O = 5-Me-3-tert-Bu-(Ar−NCH)C6H2O (1, Ar = 2,6-Me2C6H3; 2, Ar = 2,6-i-Pr2C6H3)], [Ni(Ph)(PPh3)(N,O)], with β-ketiminato ligands (N, O) [N, O = CH3COCHC(CH3)N−Ar (3, Ar = 2,6-Me2C6H3; 4, Ar = 2,6-i-Pr2C6H3)] and [Ni(N, N)(PPh3)], and with β-diketiminato ligands (N, N) [5, N, N = [2,6-i-Pr2(C6H3)NC(CH3)]2CH] have been synthesized and characterized. The molecular structures of complexes 1, 4, and 5 have been confirmed by X-ray single-crystal analyses. Although their ligands have similar structures, complex 4 possesses a structure similar to that of four-coordination nickel with complex 1, while complex 5 reveals a rare three-coordination nickel geometry. These compounds show high catalytic activities of up to 3.16 × 107 g PNB mol-1 Ni h-1 for the addition polymerization of norbornene in the presence of modified methylaluminoxane (MMAO) as cocatalyst. Catalytic activities, polymer yield, molecular weights, and molecular weight distributions of polyborbornene have been investigated under various reaction conditions.

Two structurally different polymorphs of cobalt(II) imidazolate frameworks are solvothermally synthesized by using N,N-dimethylacetamide as a template: The polymorph 6 (a = 9.797 (4) angstroms, b = 15.301(6) angstroms, c =14.902(6) angstroms, beta = 98.904(6) degrees, monoclinic, P21/n) shows structures of silicate CaAl2Si2O8 with CrB4 topology, while polymorph 7 (a = 15.173(4) angstroms, b = 15.173(4) angstroms, c = 19.089(5) angstroms, Pbca) shows CaGa2O4-related topological structures. In addition, the 7' (a = 15.9712(18) angstroms, b = 15.9253(19) angstroms, c = 18.475(2) angstroms, Pbca), a compound isostructural with 7, is synthesized by using cyclohexanol as a template. Thus, these cobalt(II) imidazolate polymers are reminiscent of the zeolite syntheses in that not only the same topological structure can be synthesized by using the different organic templates, but also different topological structures can be synthesized by using the same organic template.