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The precise identification of metal–metal bonds is critical to fully understanding the nature of metal–metal bonding but remains a fundamental challenge. Herein, we show the essence of Sc–Sc bonds ...

In situ cross-linking encapsulation has been demonstrated to be an efficient strategy for enhancing the humidity stability of perovskite solar cells (PSCs). In this study, a novel cross-linkable fullerene derivative, namely 1-(p-benzoate-(p-methylvinylbenzene)-indolino[2,3][60] fullerene (FPPS), was readily synthesized from commercially available building blocks in two steps. This FPPS was employed as an interfacial modifier on perovskite surfaces in inverted planar p–i–n PSCs. Owing to the fast interfacial charge extraction and efficient trap passivation, PSCs based on the cross-linked FPPS (C-FPPS) exhibited excellent performance. The PSCs had a top-performing power conversion efficiency (PCE) of 17.82% with negligible hysteresis, compared to the control devices without C-PFFS (16.99%). Moreover, the strong water resistance of the C-FPPS interfacial layer distinctly enhances the ambient stability of PSC devices, exhibiting a t80 (the time required to reach 80% of the initial PCE) of 300 h under high-humidity conditions. This significantly surpasses the control devices, whose t80 was only 130 h. These results demonstrate that cross-linkable fullerene derivatives can be promising interfacial materials for designing high-efficiency, hysteresis-free, air-stable PSCs.

The structure-dependent thermal stability of fullerene electron transport layers (ETLs) and its impact on device stability have been underrated for years. Based on cocrystallographic understanding, herein, we develop a thermally stable ETL comprising a hybrid layer of [6,6]-phenyl-C

All previously reported C70 isomers have positive curvature and contain 12 pentagons in addition to hexagons. Herein, we report a new C70 species with two negatively curved heptagon moieties and 14 pentagons. This unconventional heptafullerene[70] containing two symmetric heptagons, referred to as dihept-C70 , grows in the carbon arc by a theoretically supported pathway in which the carbon cluster of a previously reported C66 species undergoes successive C2 insertion via a known heptafullerene[68] intermediate with low energy barriers. As identified by X-ray crystallography, the occurrence of heptagons facilitates a reduction in the angle of the π-orbital axis vector in the fused pentagons to stabilize dihept-C70 . Chlorination at the intersection of a heptagon and two adjacent pentagons can greatly enlarge the HOMO-LUMO gap, which makes dihept-C70 Cl6 isolable by chromatography. The synthesis of dihept-C70 Cl6 offers precious clues with respect to the fullerene formation mechanism in the carbon-clustering process.

A general one-step synthesis of symmetrical or unsymmetrical 1,4-di(organo)fullerenes from organo(hydro)fullerenes (RC60H) is realized by direct oxidative arylation. The new combination of catalytic trifluoromethanesulfonic acid (TfOH) and stoichiometric o-chloranil is the first to be used to directly generate an R-C60+ intermediate from common RC60H. Unexpectedly, the in situ generated R-C60+ intermediate is shown to be quite stable in whole 13C NMR spectroscopy characterization in the absence of cation quenching reagents. Because the direct oxidation of common RC60H to form the corresponding R-C60+ has never been realized, the present combination of TfOH and o-chloranil solves the challenges associated with the formation of stable RC60+ cations from common RC60H without any coordination of an R group.

In regular perovskite solar cells (PSCs), the commonly used electron transport layer (ETL) is titanium oxide (TiO2). Nevertheless, the preparation of a high-quality TiO2 ETL demands an elevated-tem...

The synthesis, structures and properties of three new Zn2+-trimesate (BTC3−) coordination polymers (CPs), {[Zn(BTC) (NH3)2]·2H2O}n (1), {[Zn3(BTC)2(NH3)2(H2O)6]·2H2O}n (2) and {[Zn3(BTC)2(NH3)6]·5H2O}n (3), have been reported. They were isolated under the ammoniacal circumstance by dissolving 1,3,5-benzenetricarboxylic acid (H3BTC) and zinc acetate in different mixed-solvents. The three CPs were comprehensively characterized by single-crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, elemental analysis and Fourier Transform Infrared analysis. Their photoluminescence properties were also studied. The results reveal that solvents play important roles on the structures and topologies of the obtained CPs. The crystallographic studies manifest that the CPs 1–3 are 1D chain, 1D ladder and 2D layer structures, respectively.

The combustion has long been applied for industrial synthesis of carbon materials such as fullerenes as well as carbon particles (known as carbon black), but the components and structures of the carbon soot are far from being clarified. Herein, we retrieve an unprecedented hydrofullerene C66H4 from a soot of a low-pressure combustion of benzene-acetylene-oxygen. Unambiguously characterized by single-crystal X-ray diffraction, the C66H4 renders a nonclassical geometry incorporating two heptagons and two pairs of fused pentagons in a C2 v symmetry. The common vertexes of the fused pentagons are bonded with four hydrogen atoms to convert the hydrogen-linking carbon atoms from sp2 to sp3 hybridization, which together with the adjacent heptagons essentially releases the sp2-bond strains on the abutting-pentagon sites of the diheptagonal fused pentagon C66 (dihept-C66). DFT computations suggest the possibility for an in situ hydrogenation process leading to stabilization of the dihept-C66. In addition, the experiments have been carried out to study heptagon-dependent properties of dihept-C66H4, indicating the key responsibility of the heptagon for changing hydrocarbon activity and electronic properties. The present work with the unprecedented double-heptagon-containing hydrofullerene successfully isolated and identified as one of the low-pressure combustion products shows that the heptagon is a new building block for constructing fullerene products in addition to pentagons and hexagons in low-pressure combustion systems.

Gaseous compounds are usually on-line detectable on sensors. The limitations of conventional sensors are suffering from incapability for exactly identifying multiple components as well as incompatibility to possible toxicants in every odor sample. Herein, we discuss an inlet modification to the laboratory standard mass spectrometer, inspired by the sensitive olfactory systems of animals, for direct sniffing, established by connecting a mini pump to the nebulizer gas tubing. The modified mass spectrometry method-sniffing-mass spectrometry (sniffing-MS)-can acquire detailed fingerprint spectra of mixed odors and shows high tolerance to toxicants. Furthermore, the method has a low limit of detection in the order of parts per trillion and is a sampling-free technique for analyzing various gaseous compounds simultaneously, thus offering versatility for smelling daily commodities, tracking diffusion, and locating position of odors. Sniffing-MS can mimic or even surpass the olfaction of animals and is applicable for analyzing gaseous/volatile compounds, especially those polar compounds, in a simple manner depending on the intrinsic molecular mass-to-charge ratio.

Three series of copper hydride clusters [Cu8H6L6]2+ (1), [Cu4HX2L4]+ where X− = Cl− (2a), Br− (2b), I− (2c), N3− (2d) and SCN− (2e), and [Cu4HX3L3] where X− = Br− (3b) and I− (3c) (L = 2-(diphenylphosphino)pyridine, dppy) were synthesized and characterized by single-crystal X-Ray crystallography and standard spectroscopic techniques. The metal core of 1, Cu8, can be described as a bicapped octahedron, while those of 2 and 3 series adopt tetrahedral structures. The hydride positions were deduced from difference electron density maps and corroborated by NMR and DFT calculations. For 1, there are two μ4-H−, one each in the two tetrahedral cavities of the two capping atoms and four μ3-H− on the six triangular faces around the waist of the octahedron. For [Cu4HX2L4]+ and [Cu4HX3L3] series, the single μ4-H− resides in the center of the Cu4 tetrahedron. It was found that these three series of copper clusters are intimately connected and can convert from one to another under specific reaction conditions. Their transformation pathways were investigated in detail. Spontaneous resolution to form optically pure enantiomeric single crystals was observed for [Cu4H(SCN)2L4]+ (2e) and [Cu4HBr3L3] (3b). Photoluminescence was observed for [Cu4HX2L4]+, as well as [Cu4HX3L3] with strong emissions from green to yellow regions.

Interface engineering that involves in the metal cathodes and the electron transport layers (ETLs) facilitates the simultaneous improvement of device performances and stability in perovskite solar cells (PSCs). Herein, low-temperature solution-processed cerium oxide (CeOx) films are prepared by a facile sol-gel method and employed as the interface layers between [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) and an Ag back contact to form PC61BM/CeOx double ETLs. The introduction of CeOx enables electron extraction to the Ag electrode and protects the underlying perovskite layer and thus improves the device performance and stability of the p-i-n PSCs. The p-i-n PSCs with double PC61BM/CeOx ETLs demonstrate a maximum power conversion efficiency (PCE) of 17.35%, which is superior to those of the devices with either PC61BM or CeOx single ETLs. Moreover, PC61BM/CeOx devices exhibit excellent stability in light soaking, which is mainly due to the chemically stable CeOx interlayer. The results indicate that CeOx is a promising interface modification layer for stable high-efficiency PSCs.

Four silver(I) coordination polymers (CPs), namely {Ag3(cpyz)(btc)}n (1), {Ag2(cpyz)(pta)}n (2), {Ag3(mpyz)2(btc)·2(H2O)}n (3), {Ag2(mpyz)(pta)·2(H2O)}n (4), [cpyz = 2-chloropyrazine, H3btc = 1,3,5-benzene tricarboxylic, mpyz = 2,6-dimethylpyrazine, H2pta = phthalic acid] have been synthesized and characterized. X-ray diffraction indicates that, 1 shows a 3D supramolecular structure with a 1D silver chain containing an infinite Ag3 units; 2 features a 3D supramolecular framework with Ag-O and Ag-Ag interaction and cpyz ligand adopts monodentate mode making no contribution to the dimensionality; in 3, the silver atom links mpyz ligand and btc anion into a 2D layer connected by Ag-Ag interaction between neighboring layers into the 3D network, with Zigzag Ag4 units; in 4, Ag(I) coordinates pta benzene dicarboxylates to generate a one-dimensional infinite chain, connecting by nitrogen ligand to exhibit a 2D 44-sql network. The results suggest that benzene dicarboxylates and the kinds of pyrazine derivatives play significant roles in the formation of such coordination architectures. The photoluminescence and thermogravimetric analysis (TGA) of the complexes were measured.

Arc-discharge of graphite is the most prevalent technique for synthesis of novel fullerenes, but the extreme conditions of the carbon arc prevent any currently available instrument from detecting the reaction species inside. To detour the difficulties for probing the derivatization mechanism in the drastic arc-discharge conditions, C78Cl6(C5Cl6) with prototypical C2v(2)-C78 cage has been isolated and characterized in the products of the chlorine-involving carbon arc. The structure of C2v(2)-C78Cl6(C5Cl6), featuring with fullerene C2v(2)-C78 doubly functionalized by chlorine atoms and perchlorinated cyclopentadiene, has been identified by X-ray crystallography. Confirmed by standard Density Functional Theory (DFT) calculations and Car-Parrinello simulations as well as mass spectrometry, the fullerene core has been revealed to form firstly followed then by reaction with chlorine atoms and afterwards with perchlorinated cyclopentadiene, with implication about stepwise reaction temperatures and sequences for the formation of fullerenes and their derivatives in the otherwise inaccessible extreme conditions of the carbon arc.

Four silver(I) coordination polymers based on 2,6-dimethylpyrazine(dmpz), {Ag2(dmpz)(L1)}n (1), {Ag2(dmpz)(L2)}n (2), {Ag2(dmpz)(L3)0.5·H2O}n (3) and {Ag6(dmpz)6(L4)2·2H2O}n (4) (H2L1 = 5-Nitroisophthalic acid, H2L2 = 3-Nitrophthalic acid, H4L3 = Pyromellitic acid, H2L4 = 5-Sulfoisophthalic acid), were synthesized under the ammoniacal condition in mixed solvents and characterized by elemental analyses, IR spectra and single-crystal X-ray diffraction. 1 contains rhombic Ag4 unit, but 4 exhibits Zigzag Ag4 unit, both with 2D double layer architecture. In 2, L2 anions link Ag pairs into 1D corrugated chains, which are further connected by dmpz ligand into 2D 44-sql network. 3 possess 3D supramolecular framework resulting from Ag O and Ag N interaction and Zigzag Ag4 units. Ag Ag interactions exist in four coordination polymers. Benzene dicarboxylates and pyrazine ligands play vital roles in formation of the multiple architectures. Photoluminescence and thermogravimetry of the complexes were also measured.

Two fullerene C 60 derivatives, 2-(3-ethoxycarbonylpropyloxy)-(5,8)-dihydronaphthyl-(6,7)-[6,6]-C 60 (EDNC) and 2-benzyloxy-(5,8)-dihydronaphthyl-(6,7)-[6,6]-C 60 (BDNC), are introduced into p-i-n type planar heterojunction perovskite solar cells as electron transport materials (ETMs) to investigate electrochemical, charge-transporting, and film-forming properties of fullerene ETMs and the resulting photovoltaic performance in comparison with [6,6]-phenyl-C 61 -butyric acid methyl ester (PC 61 BM). Due to better surface morphology, the EDNC-involving device shows better performance (12.64%) than that of BDNC-based device (7.36%) despite of their similar LUMO energy level, electron mobility, optical properties, and electrochemical properties. Higher power conversion efficiency (PCE) of 15.04% is achieved using PC 61 BM as the ETM, the electronic mobility of PC 61 BM is approximately one order of magnitude higher than that of EDNC, which leads to slightly higher short-circuit current density and fill factor for PC 61 BM-based device. This work demonstrates that factors such as electron mobility and surface morphology should be envisaged in searching for fullerene derivatives as efficient ETM in perovskite solar cells.

Organic–inorganic perovskite solar cells have emerged as a promising photovoltaic technology because of their advantages such as low cost, high efficiency, and solution processability. The performance of perovskite solar cells is highly dependent on the crystallinity and morphology of the perovskite films. Herein, we report a simple, one-step anti-solvent deposition process using di-isopropyl ether as a dripping solvent to obtain extremely uniform and highly crystalline CH3NH3PbI3 perovskite films. Compared to toluene, chlorobenzene, chloroform, or diethyl ether, di-isopropyl ether has proven to be a more suitable solvent for an anti-solvent deposition process. The perovskite solar cells fabricated by the anti-solvent deposition process using di-isopropyl ether treatment exhibit an average power conversion efficiency (PCE) of 17.67 ± 0.54% and the highest PCE of 19.07%. Moreover, the higher boiling point of di-isopropyl ether makes the anti-solvent deposition process more tolerant to elevated ambient temperature, which can be carried out at ambient temperatures up to 40 °C. Our results demonstrate that di-isopropyl ether is an excellent dripping solvent in the anti-solvent deposition process for efficient and reproducible perovskite solar cells.

Discovery of organic-inorganic hybrid perovskites ignites the dream of next-generation solar cells fabricated by low-cost solution processing. To date, fullerene derivative [6,6]-phenyl-C61- butyric acid methyl ester (PC61BM), is the most prevalently used electron transport layer for high efficiency p-i-n planar heterojunction perovskite solar cells. Compared with PC61BM, pristine fullerenes, such as C60 and C70, have shown superiority of higher electron mobility and much lower costs. Due to the poor solubility and strong tendency to crystallize for pristine fullerenes in solution process, it is still a challenge to deposit compact and continuous film of pristine fullerenes for p-i-n type perovskite solar cells by solution processing. Herein, solution processed pristine fullerenes (C60 and C70) were used as electron transport layers to replace PC61BM in perovskite solar cells with high performance and enhanced stability. Power conversion efficiency of 14.04% was obtained by using mixture of C60 and C70 as electron transport layer, which is comparable to that of PC61BM based device (13.74%). We demonstrated that the strong tendency of pristine fullerenes to crystallize during solvent removal can be largely mitigated by mixing different kinds of pristine fullerenes. These findings implicate pristine fullerenes as promising electron transport layers for high performance perovskite solar cells.

In high performance perovskite solar cells (PSCs), the electron transport layer (ETL) has overwhelmingly been dominated by compact titanium oxide (TiO2), which typically requires sintering at around 500 °C. Such a high-temperature sintering procedure prevents TiO2-based PSCs from matching well with plastic substrates and low-cost manufacturing. Here we report cerium oxide (CeOx, x = 1.87), that was prepared facilely through a simple sol–gel method at low temperature (∼150 °C), as an alternative to high-temperature sintering processed TiO2 in the regular architecture of PSCs. With a PCE of 14.32% from the involvement of an optimized CeOx ETL through adjusting the precursor solution, and a higher PCE of 17.04% through introducing a [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) interfacial layer between the CeOx ETL and the perovskite layer, the present work about CeOx-based PSCs renders low-temperature solution-processed CeOx an excellent ETL for high performance perovskite solar cells with improved stability.

Despite being widely used as electron acceptor in polymer solar cells, commercially available PC71BM (phenyl-C71-butyric acid methyl ester) usually has a "random" composition of mixed regioisomers or stereoisomers. Here the PC71BM has been isolated into three typical isomers, α-, β1- and β2-PC71BM, for establishing the isomer-dependent photovoltaic performance on change of ternary composition of α-, β1- and β2-PC71BM. Mixing the isomers in a ratio of α:β1:β2=8:1:1 resulted in the best power conversion efficiency (PCE) of 7.67% for the polymer solar cells with PTB7:PC71BM as photoactive layer (PTB7 = poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]]). The three typical PC71BM isomers, even though sharing similar LUMO energy level and light absorption, render starkly different photovoltaic performances with average-performing PCE of 1.28-7.44% due to diverse self-aggregation of individual or mixed PC71BM isomers in the otherwise same polymer solar cells.

The combustion has long been applied for industrial synthesis of carbon materials such as fullerenes as well as carbon particles (known as carbon black), but the components and structures of the carbon soot are far from being clarified. Herein, we retrieve an unprecedented hydrofullerene C

The assembly of spherical fullerenes, or buckyballs, into single crystals for crystallographic identification often suffers from disordered arrangement. Here we show a chiral configuration of decapyrrylcorannulene that has a concave ‘palm’ of corannulene and ten flexible electron-rich pyrryl group ‘fingers’ to mimic the smart molecular ‘hands’ for self-adaptably cradling various buckyballs in a (+)hand-ball-hand(−) mode. As exemplified by crystallographic identification of 15 buckyball structures representing pristine, exohedral, endohedral, dimeric and hetero-derivatization, the pyrryl groups twist with varying dihedral angles to adjust the interaction between decapyrrylcorannulene and fullerene. The self-adaptable electron-rich pyrryl groups, susceptible to methylation, are theoretically revealed to contribute more than the bowl-shaped palm of the corannulene in holding buckyball structures. The generality of the present decapyrrylcorannulene host with flexible pyrryl groups facilitates the visualization of numerous unknown/unsolved fullerenes by crystallography and the assembly of the otherwise close-packed spherical fullerenes into two-dimensional layered structures by intercalation., The structures of fullerenes, or buckyballs, are often very difficult to resolve. Here, the authors describe a decapyrrylcorannulene host with ten flexible pyrryl groups that can efficiently co-crystallize with diverse fullerene derivatives in a ‘hand-ball-hand’ fashion, allowing crystallographic identification of commonly known types of fullerenes.

A carboncone[1,2] molecule was rationally synthesized, pushing the study on all-carbon allotropes into a new dimension., Carboncones, a special family of all-carbon allotropes, are predicted to have unique properties that distinguish them from fullerenes, carbon nanotubes, and graphenes. Owing to the absence of methods to synthesize atomically well-defined carboncones, however, experimental insight into the nature of pure carboncones has been inaccessible. Herein, we describe a facile synthesis of an atomically well-defined carboncone[1,2] (C70H20) and its soluble penta-mesityl derivative. Identified by x-ray crystallography, the carbon skeleton is a carboncone with the largest possible apex angle. Much of the structural strain is overcome in the final step of converting the bowl-shaped precursor into the rigid carboncone under mild reaction conditions. This work provides a research opportunity for investigations of atomically precise single-layered carboncones having even higher cone walls and/or smaller apex angles.

Filiació URV: SI As a bridge to connect medium-sized fullerenes, fused-pentagon C74 is still missing heretofore. Of 14-246 possible isomers, the first fused-pentagon C74 with the Fowler-Manolopoulos code of 14-049 was stabilized as C74Cl10 in the chlorine-involving carbon arc. The structure of C74Cl10 was identified by X-ray crystallography. The stabilization of pristine fused-pentagon C74 by stepwise chlorination was clarified in both theoretical simulation with density functional theory calculations and experimental fragmentation with multistage mass spectrometry.

Four mixed-ligand silver(I) coordination polymers (CPs) {Ag2(tpyz)(L)}_n (1), {Ag4(tpyz)2(L)2}_n (2), {Ag2(mpyz)(L)}_n (3) as well as its isomer (4), (tpyz-2,3,5-trimethylpyrazine, mpyz = 2,3,5,6-tetramethylpyrazine, H2L = (+)-camphoric acid), were synthesized with reactions of L and pyrazine derivatives with silver nitrate in different solvent systems. Systematic characterizations with single-crystal X-ray diffraction indicate that, 1 and 3 show a 3D framework which constructed by silver(I) and L anion, the pyrazine derivatives only give one N to connect to metal, which may be due to the disorder of the methyl which shares the same carbon with carboxylate; 2 and 4 demonstrate a 2D 4 4–sql network. The difference between two: one structure is single layer and the other is double layer. Furthermore, 4 contains a 1D helical chains which connected by Ag(I) and mpyz ligand. Meanwhile, the L anion exhibits different coordination modes in 1–4. 1–4 spanning from two-dimensional network to three-dimensional framework suggest that the kinds of pyrazine derivatives and solvents play significant roles in the formation of such coordination architectures. The thermogravimetric analyses (TGA), IR, and photoluminescence were also measured.

Three mix-ligand Ag(I) coordination compounds, namely, {[Ag10(tpyz) 5(L1) 5(H2 O)2].(H2 O)4}n (1, tpyz = 2,3,4,5-tetramethylpyrazine, H2 L1 = phthalic acid), [Ag4(tpyz) 2(L2) 2(H2 O)].(H2 O)5}n (2, H2 L2 = isophthalic acid) {[Ag2(tpyz) 2(L3) (H2 O)4].(H2 O)8}n (3, H2 L3 = terephthalic acid), have been synthesized and characterized by elemental analysis, IR, PXRD and X-ray single-crystal diffraction. 1 exhibits a 2D layer which can be simplified as a (4,4) net. 2 is a 3D network which can be simplified as a (3,3)-connected 2-nodal net with a point symbol of {102.12}{102}. 3 consists of linear [Ag(tpyz) (H2 O)2]n chain. Of particular interest, discrete hexamer water clusters were observed in 1 and 2, while a 2D L10(6) water layer exists in 3. The results suggest that the benzene dicarboxylates play pivotal roles in the formation of the different host architectures as well as different water aggregations. Moreover, thermogravimetric analysis (TGA) and emissive behaviors of these compounds were investigated.

Six coordination compounds of Ag(I) and 2,4-diamino-6-[2-(2-methyl-1-imidazolyl)ethyl]-1,3,5-triazine (L, Ag:L = 1:2) with different anions and solvents, namely, [Ag(L)2]∙(NO3)∙4(H2O) (1), [ Ag ( L ) 2 ] · 1 / 2 ( nds ) · ( MeOH ) · ( H 2 O ) (2, H2nds = 1,5-naphthalenedisulfonic acid), [ Ag ( L ) 2 ] · 1 / 2 ( nds ) · ( MeOH ) · 5 / 2 ( H 2 O ) (3), [ Ag ( L ) 2 ] · 1 / 2 ( nds ) · ( CH 3 CN ) (4), [Ag(L)2]∙(ClO4)∙(MeOH)∙(H2O) (5), and [Ag(L)2]∙(ClO4)∙2(H2O) (6), have been synthesized and characterized by elemental analysis, IR, PXRD and X-ray single-crystal diffraction. In these compounds, each Ag(I) ion is ligated by two imidazole nitrogens to form a Ag(L)2 unit. The anions and solvents determine hydrogen-bonding between the DAT groups links the Ag(L)2 units whether to form chains in 1 and 2 or layers in 3–6. In addition, thermogravimetric analysis (TGA) and luminescent properties of these compounds were also investigated.

Achiral ligand- and Ag(I)-driven spontaneous resolution occurred simultaneously in the formation of two enantiomers 1P and 1M of [Ag2(5-nip)(mpyz)] (5-nip = 5-nitroisophthalic, mpyz = 2,3,5,6-tetramethylpyrazine), whose absolute sense of a helix made of achiral components is induced by the metal Ag(I) through argentophilic interactions.

Two stereomers of bisadduct analogues of [6, 6]-phenyl-C71-butyric acid methyl ester (bisPC71BM) were synthesized and their geometrical structures with cis- or trans-configuration were identified by X-ray crystallography. Although both of the bisPC71BM have similar spectrometric and electrochemical properties, the spatial orientation of the two addition groups on C70 has impact on crystal packing and molecular assembly of bisPC71BM isomers and, in turn, photovoltaic performance in polymer solar cell based on poly(3-hexylthiophene) (P3HT) (with power conversion efficiency of 1.72 % and 1.84 % for the solar cells involving cis- and trans-bisPC71BM, respectively). Although the power conversion efficiency remains to be improved, this work exemplifies that the photovoltaic properties of fullerene-based electron acceptors are influenced by aggregation of the stereomeric molecules and thus extends the guidelines for rational design of efficient fullerene acceptor.

Five one-dimensional to three-dimensional coordination polymers have been synthesized by 2-chlorobenzoic acid (HL1), 2-nitrobenzoic acid (HL2), o-toluic acid (HL3), 2,3,5-trimethylpyrazine (tpyz) and 2,3,5,6-tetramethylpyrazine (mpyz) in the presence of NH3·H2O in mixed solvents systems, namely, {Ag4(tpyz)2(L1)4}n (1), {Ag2(tpyz) (L2)2}n (2), {Ag2(tpyz) (L3)2}n (3), {Ag2(mpyz) (L1)2}n (4), {Ag(mpyz) (L2) (H2O)}n (5). All the complexes have been characterized by elemental analyses, IR spectra and X-ray diffraction. Compound 1 shows a 3D framework. The tpyz ligand links 1D chain which was connected by silver atom and L1 anion into 3D framework. Compounds 2 and 4 possess a similar 2D network with (4, 4) topology. Complex 3 also exhibits a two-dimensional structure. There is a 1D silver chain in 3, which is the main difference from 2 and 4. So, 3 shows three-connected (4 8, 3) topology. For 5, only one oxygen of L2 coordinated to Ag(I) ions. The L2 anions were arranged in both sides of the chain, which was connected by silver atoms and mpyz ligands. Then, the uncoordinated carboxylate oxygen with coordinated water 1molecule oxygen through the hydrogen bond made the resultant structure to a 3D framework. Complexes 1–5 spanning from one-dimensional chains to three-dimensional framework suggest that carboxylates and the kinds of pyrazine derivatives play significant roles in the formation of such coordination architectures. The photoluminescence and thermogravimetric analysis (TGA) of the complexes were also investigated.