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1.
Dr. Yun-Nan Gong Dr. Long Jiao Yunyang Qian Prof. Dr. Chun-Yang Pan Dr. Lirong Zheng Dr. Xuechao Cai Prof. Dr. Bo Liu Prof. Dr. Shu-Hong Yu Prof. Dr. Hai-Long Jiang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(7):2727-2731
The general synthesis and control of the coordination environment of single-atom catalysts (SACs) remains a great challenge. Herein, a general host–guest cooperative protection strategy has been developed to construct SACs by introducing polypyrrole (PPy) into a bimetallic metal–organic framework. As an example, the introduction of Mg2+ in MgNi-MOF-74 extends the distance between adjacent Ni atoms; the PPy guests serve as N source to stabilize the isolated Ni atoms during pyrolysis. As a result, a series of single-atom Ni catalysts (named NiSA-Nx-C) with different N coordination numbers have been fabricated by controlling the pyrolysis temperature. Significantly, the NiSA-N2-C catalyst, with the lowest N coordination number, achieves high CO Faradaic efficiency (98 %) and turnover frequency (1622 h−1), far superior to those of NiSA-N3-C and NiSA-N4-C, in electrocatalytic CO2 reduction. Theoretical calculations reveal that the low N coordination number of single-atom Ni sites in NiSA-N2-C is favorable to the formation of COOH* intermediate and thus accounts for its superior activity. 相似文献
2.
Yulin Wang Run Shi Lu Shang Geoffrey I. N. Waterhouse Jiaqi Zhao Qinghua Zhang Lin Gu Tierui Zhang 《Angewandte Chemie (International ed. in English)》2020,59(31):13057-13062
Carbon‐supported NiII single‐atom catalysts with a tetradentate Ni‐N2O2 coordination formed by a Schiff base ligand‐mediated pyrolysis strategy are presented. A NiII complex of the Schiff base ligand (R,R)‐(?)‐N,N′‐bis(3,5‐di‐tert‐butylsalicylidene)‐1,2‐cyclohexanediamine was adsorbed onto a carbon black support, followed by pyrolysis of the modified carbon material at 300 °C in Ar. The Ni‐N2O2/C catalyst showed excellent performance for the electrocatalytic reduction of O2 to H2O2 through a two‐electron transfer process in alkaline conditions, with a H2O2 selectivity of 96 %. At a current density of 70 mA cm?2, a H2O2 production rate of 5.9 mol gcat.?1 h?1 was achieved using a three‐phase flow cell, with good catalyst stability maintained over 8 h of testing. The Ni‐N2O2/C catalyst could electrocatalytically reduce O2 in air to H2O2 at a high current density, still affording a high H2O2 selectivity (>90 %). A precise Ni‐N2O2 coordination was key to the performance. 相似文献
3.
Li‐Yan Wang Yan‐Fen Peng Yu‐Ping Zhang Bao‐Long Li Yong Zhang 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(7):m297-m299
The coordination geometry of the NiII atom in the title complex, poly[diazidobis[μ‐1,4‐bis(1,2,4‐triazol‐1‐ylmethyl)benzene‐κ2N4:N4′]nickel(II)], [Ni(N3)2(C12H12N6)2]n, is a distorted octahedron, in which the NiII atom lies on an inversion centre and is coordinated by four N atoms from the triazole rings of two symmetry‐related pairs of 1,4‐bis(1,2,4‐triazol‐1‐ylmethyl)benzene (bbtz) ligands and two N atoms from two symmetry‐related monodentate azide ligands. The NiII atoms are bridged by four bbtz ligands to form a two‐dimensional (4,4)‐network. 相似文献
4.
Xin Rong Hong‐Juan Wang Xiu‐Li Lu Rui Si Tong‐Bu Lu 《Angewandte Chemie (International ed. in English)》2020,59(5):1961-1965
The reaction of precursors containing both nitrogen and oxygen atoms with NiII under 500 °C can generate a N/O mixing coordinated Ni‐N3O single‐atom catalyst (SAC) in which the oxygen atom can be gradually removed under high temperature due to the weaker Ni?O interaction, resulting in a vacancy‐defect Ni‐N3‐V SAC at Ni site under 800 °C. For the reaction of NiII with the precursor simply containing nitrogen atoms, only a no‐vacancy‐defect Ni‐N4 SAC was obtained. Experimental and DFT calculations reveal that the presence of a vacancy‐defect in Ni‐N3‐V SAC can dramatically boost the electrocatalytic activity for CO2 reduction, with extremely high CO2 reduction current density of 65 mA cm?2 and high Faradaic efficiency over 90 % at ?0.9 V vs. RHE, as well as a record high turnover frequency of 1.35×105 h?1, much higher than those of Ni‐N4 SAC, and being one of the best reported electrocatalysts for CO2‐to‐CO conversion to date. 相似文献
5.
Marco A. García-Eleno Magdalena Quezada-Miriel Reyna Reyes-Martínez Simn Hernndez-Ortega David Morales-Morales 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(5):393-397
Pincer complexes can act as catalysts in organic transformations and have potential applications in materials, medicine and biology. They exhibit robust structures and high thermal stability attributed to the tridentate coordination of the pincer ligands and the strong σ metal–carbon bond. Nickel derivatives of these ligands have shown high catalytic activities in cross‐coupling reactions and other industrially relevant transformations. This work reports the crystal structures of two polymorphs of the title NiII POCOP pincer complex, [Ni(C29H41N2O8P2)Cl] or [NiCl{C6H2‐4‐[OCOC6H4‐3,5‐(NO2)2]‐2,6‐(OPtBu2)2}]. Both pincer structures exhibit the NiII atom in a distorted square‐planar coordination geometry with the POCOP pincer ligand coordinated in a typical tridentate manner via the two P atoms and one arene C atom via a C—Ni σ bond, giving rise to two five‐membered chelate rings. The coordination sphere of the NiII centre is completed by a chloride ligand. The asymmetric units of both polymorphs consist of one molecule of the pincer complex. In the first polymorph, the arene rings are nearly coplanar, with a dihedral angle between the mean planes of 27.9 (1)°, while in the second polymorph, this angle is 82.64 (1)°, which shows that the arene rings are almost perpendicular to one another. The supramolecular structure is directed by the presence of weak C—H…O=X (X = C or N) interactions, forming two‐ and three‐dimensional chain arrangements. 相似文献
6.
Bi‐Yun Su Jia‐Xiang Wang Xiang Liu Qian‐Ding Li 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(8):851-854
In the title compound, [Ni(C12H11N2)2], the NiII cation lies on an inversion centre and has a square‐planar coordination geometry. This transition metal complex is composed of two deprotonated N,N′‐bidentate 2‐[(phenylimino)ethyl]‐1H‐pyrrol‐1‐ide ligands around a central NiII cation, with the pyrrolide rings and imine groups lying trans to each other. The Ni—N bond lengths range from 1.894 (3) to 1.939 (2) Å and the bite angle is 83.13 (11)°. The Ni—N(pyrrolide) bond is substantially shorter than the Ni—N(imino) bond. The planes of the phenyl rings make a dihedral angle of 78.79 (9)° with respect to the central NiN4 plane. The molecules are linked into simple chains by an intermolecular C—H...π interaction involving a phenyl β‐C atom as donor. Intramolecular C—H...π interactions are also present. 相似文献
7.
From Metal–Organic Frameworks to Single‐Atom Fe Implanted N‐doped Porous Carbons: Efficient Oxygen Reduction in Both Alkaline and Acidic Media 下载免费PDF全文
Long Jiao Gang Wan Rui Zhang Dr. Hua Zhou Prof. Dr. Shu‐Hong Yu Prof. Dr. Hai‐Long Jiang 《Angewandte Chemie (International ed. in English)》2018,57(28):8525-8529
It remains highly desired but a great challenge to achieve atomically dispersed metals in high loadings for efficient catalysis. Now porphyrinic metal–organic frameworks (MOFs) have been synthesized based on a novel mixed‐ligand strategy to afford high‐content (1.76 wt %) single‐atom (SA) iron‐implanted N‐doped porous carbon (FeSA‐N‐C) via pyrolysis. Thanks to the single‐atom Fe sites, hierarchical pores, oriented mesochannels and high conductivity, the optimized FeSA‐N‐C exhibits excellent oxygen reduction activity and stability, surpassing almost all non‐noble‐metal catalysts and state‐of‐the‐art Pt/C, in both alkaline and more challenging acidic media. More far‐reaching, this MOF‐based mixed‐ligand strategy opens a novel avenue to the precise fabrication of efficient single‐atom catalysts. 相似文献
8.
Cengiz Arici Filiz Ercan Raif Kurtaran Orhan Atakol 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(7):812-814
In the title compounds, {2,2′‐[2,2‐dimethyl‐1,3‐propanediylbis(nitrilomethylidyne)]diphenolato‐κ4N,N′,O,O′}nickel(II), [Ni(C19H20N2O2)], and {2,2′‐[2,2‐dimethyl‐1,3‐propanediylbis(nitrilomethylidyne)]diphenolato‐κ4N,N′,O,O′}copper(II), [Cu(C19H20N2O2)], the NiII and CuII atoms are coordinated by two iminic N and two phenolic O atoms of the N,N′‐bis(salicylidene)‐2,2‐dimethyl‐1,3‐propanediaminate (SALPD2?, C17H16N2O22?) ligand. The geometry of the coordination sphere is planar in the case of the NiII complex and distorted towards tetrahedral for the CuII complex. Both complexes have a cis configuration imposed by the chelate ligand. The dihedral angles between the N/Ni/O and N/Cu/O coordination planes are 17.20 (6) and 35.13 (7)°, respectively. 相似文献
9.
Cheng Tang Yan Jiao Bingyang Shi Jia‐Ning Liu Zhenhua Xie Xiao Chen Qiang Zhang Shi‐Zhang Qiao 《Angewandte Chemie (International ed. in English)》2020,59(23):9171-9176
Single‐atom catalysts (SACs) have great potential in electrocatalysis. Their performance can be rationally optimized by tailoring the metal atoms, adjacent coordinative dopants, and metal loading. However, doing so is still a great challenge because of the limited synthesis approach and insufficient understanding of the structure–property relationships. Herein, we report a new kind of Mo SAC with a unique O,S coordination and a high metal loading over 10 wt %. The isolation and local environment was identified by high‐angle annular dark‐field scanning transmission electron microscopy and extended X‐ray absorption fine structure. The SACs catalyze the oxygen reduction reaction (ORR) via a 2 e? pathway with a high H2O2 selectivity of over 95 % in 0.10 m KOH. The critical role of the Mo single atoms and the coordination structure was revealed by both electrochemical tests and theoretical calculations. 相似文献
10.
Ergui Luo Hao Zhang Xian Wang Liqin Gao Liyuan Gong Tuo Zhao Zhao Jin Junjie Ge Zheng Jiang Changpeng Liu Wei Xing 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(36):12599-12605
Single‐atom catalysts (SACs) are attracting widespread interest for the catalytic oxygen reduction reaction (ORR), with Fe?Nx SACs exhibiting the most promising activity. However, Fe‐based catalysts suffer serious stability issues as a result of oxidative corrosion through the Fenton reaction. Herein, using a metal‐organic framework as an anchoring matrix, we for the first time obtained pyrolyzed Cr/N/C SACs for the ORR, where the atomically dispersed Cr is confirmed to have a Cr?N4 coordination structure. The Cr/N/C catalyst exhibits excellent ORR activity with an optimal half‐wave potential of 0.773 V versus RHE. More excitingly, the Fenton reaction is substantially reduced and, thus, the final catalysts show superb stability. The innovative and robust active site for the ORR opens a new possibility to circumvent the stability issue of the non‐noble metal ORR catalysts. 相似文献
11.
brahim Uar Ahmet Bulut Okan Zafer Yeilel Halis
lmez Orhan Büyükgüngr 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(11):m563-m566
The title mononuclear complex, [Ni(C5H2N2O4)(C3H4N2)2(H2O)2] or [Ni(HOr)(im)2(H2O)2] (im is imidazole and H3Or is orotic acid, or 2,6‐dioxo‐1,2,3,6‐tetrahydropyrimidine‐4‐carboxylic acid), has been synthesized and the crystal structure determination is reported. The NiII ion in the complex has a distorted octahedral coordination geometry comprised of one deprotonated pyrimidine N atom and the adjacent carboxylate O atom of the orotate ligand, two tertiary imidazole N atoms and two aqua ligands. An extensive three‐dimensional network of OW—H⋯O and N—H⋯O hydrogen bonds, and π–π and π–ring interactions are responsible for crystal stabilization. 相似文献
12.
Sladjana B. Novakovi Goran A. Bogdanovi Ilija D. Br
eski Vukadin M. Leovac 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(7):m263-m265
The title compound, [Ni(C20H17N3OP)(N3)], is the first complex with a semicarbazide‐based ligand having a P atom as one of the donors. The influence of the P atom on the deformation of the coordination geometry of the NiII ion is evident but less expressed than in the cases of complexes with analogous seleno‐ and thiosemicarbazide ligands. The torsion angles involving the two bonds formed by the P atom within the six‐membered chelate ring have the largest values [C—P—Ni—N = 24.3 (2)° and C—C—P—Ni = −24.2 (4)°], suggesting that the P atom considerably influences the conformation of the ring. Two types of N—H...N hydrogen bond connect the complex units into chains. 相似文献
13.
Complexes of Nickel(II) with Oxalic Amidines and Oxalic Amidinates with Additonal R2P‐Donor Groups Oxalamidines R1N=C(NHR2)‐C(=NHR2)=NR1, which bear additional donor atoms at two of the four N substituents ( H2A : R1 = mesityl, R2 = ‐(CH2)3‐PPh2; H2B : R1 = tolyl, R2 = ‐(CH2)3‐PMe2) form binuclear complexes with Nickel(II) in which very different coordination modes are realized. In the complex [ (A) Ni2Br2] (1) the two nickel atoms at each side of the bridge are in a square‐planar environment, coordinated by the two N donor atoms of the oxalic amidinate framework, a bromide and a Ph2P group. An analogous coordination has the organometallic compound [ (A) Ni2Me2] (2) . In contrast, the two nickel atoms in the compound {[( B )][Ni(acac)]2} (5) differ in their coordinative environment. At one side of the oxalic amidinate bridging ligand a (acac)Ni fragment is coordinated by the two N donor atoms resulting in a square‐planar environment. At the opposite side the (acac)Ni fragment is coordinated at the both N donor ligands of the bridging ligand as well as at the two PMe2 groups of the side chains resulting in an octahedral coordination for this nickel atom. 相似文献
14.
Olha Sereda Helen Stoeckli‐Evans 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(6):m221-m223
The structure of the title compound, [NiCu(CN)4(C10H8N2)(H2O)2]n or [{Cu(H2O)2}(μ‐C10H8N2)(μ‐CN)2{Ni(CN)2}]n, was shown to be a metal–organic cyanide‐bridged framework, composed essentially of –Cu–4,4′‐bpy–Cu–4,4′‐bpy–Cu– chains (4,4′‐bpy is 4,4′‐bipyridine) linked by [Ni(CN)4]2− anions. Both metal atoms sit on special positions; the CuII atom occupies an inversion center, while the NiII atom of the cyanometallate sits on a twofold axis. The 4,4′‐bpy ligand is also situated about a center of symmetry, located at the center of the bridging C—C bond. The scientific impact of this structure lies in the unique manner in which the framework is built up. The arrangement of the –Cu–4,4′‐bpy–Cu–4,4′‐bpy–Cu– chains, which are mutually perpendicular and non‐intersecting, creates large channels running parallel to the c axis. Within these channels, the [Ni(CN)4]2− anions coordinate to successive CuII atoms, forming zigzag –Cu—N[triple‐bond]C—Ni—C[triple‐bond]N—Cu– chains. In this manner, a three‐dimensional framework structure is constructed. To the authors' knowledge, this arrangement has not been observed in any of the many copper(II)–4,4′‐bipyridine framework complexes synthesized to date. The coordination environment of the CuII atom is completed by two water molecules. The framework is further strengthened by O—H...N hydrogen bonds involving the water molecules and the symmetry‐equivalent nonbridging cyanide N atoms. 相似文献
15.
Bi‐Yun Su Xiao‐Teng Li Jia‐Xiang Wang Xu‐Dong Wang 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(12):1053-1056
<!?tlsb=‐0.2pt>Nitrogen‐based polydentate ligands are of interest owing to their flexible complexation to transition metal atoms. For the title compound, [Ni(C15H17N2)2], a transition metal complex formed by the coordination of two identical N,N′‐bidentate mono(imino)pyrrolyl ligands to an NiII centre, an X‐ray crystal diffraction study indicates that the two ligands show an inverted arrangement with respect to one another around the NiII centre, which is located on a crystallographic inversion centre. The planes of the aromatic substituents at the imine N atoms of the ligands show dihedral angles of 85.91 (5)° with respect to the NiN4 plane. The Ni—N bond lengths are in the range 1.9072 (15)–1.9330 (15) Å and the Nimino—Ni—Npyrrole bite angles are 83.18 (6)°. The Ni—Npyrrole bond is substantially shorter than the Ni—Nimino bond. Molecules are linked into an extensive network by means of intermolecular C—H...π(arene) hydrogen bonds in which every molecule acts both as hydrogen‐bond donor and acceptor. The supramolecular assembly takes the form of an infinite two‐dimensional sheet. 相似文献
16.
Andrey I. Buvaylo Nikolay M. Dudarenko Igor O. Fritsky Jolanta
witek‐Kozowska 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(8):m331-m333
The title compound, [Ni(C2H8N2)3][Ni(C3HN3O2)2]·H2O, appears to be a modular associate consisting of two complex counter‐ions, containing bivalent nickel as the central atom in both cases, and a solvent water molecule. The NiII ion in the complex cation lies on the C2 crystallographic axis. Its coordination environment is formed by six N atoms of three ethylenediamine (en) molecules, representing a distorted octahedral geometry. The NiII ion in the complex anion occupies a position at the center of inversion. It exhibits a distorted square‐planar coordination geometry formed by four N atoms belonging to the deprotonated oxidoimine and amide groups of the two doubly charged 2‐cyano‐2‐(oxidoimino)acetamidate anions, situated in trans positions with respect to each other. In the crystal packing, the complex anions are linked by water molecules via hydrogen bonds between the amide O atoms and water H atoms, forming chains translated along the a direction. The [Ni(en)3]2+ cations fill empty spaces between the translational chains, connecting them by hydrogen bonds between the oxime and amide O atoms of the anions and the amine H atoms of the cations, forming layers along the ac plane. The water molecules provide connection between layers through N atoms of the cations, thus forming a three‐dimensional modular structure. 相似文献
17.
Liang‐Gui Wang 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(11):m479-m480
The title complex, poly[bis(μ6‐pyridine‐2,6‐dicarboxylato N‐oxide)nickel(II)disilver(I)], [Ag2Ni(C7H3NO5)2]n or [Ag2Ni(pydco)2]n (H2pydco = pyridine‐2,6‐dicarboxylic acid N‐oxide), has a two‐dimensional sheet structure. The two carboxylate groups adopt two coordination modes. The NiII ion displays a distorted octahedral geometry, bonded to two carboxylate O atoms of two different pydco ligands and four O donors from another two ligands, i.e. two carboxylate O atoms and two N‐oxide O atoms. The AgI ion adopts a tetrahedral coordination, linked by three O atoms of three different carboxylate groups and an N‐oxide O atom. 相似文献
18.
Santu Chakraborty B. Samanta C. R. Chowdhury S. Mitra Alok K. Mukherjee 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(11):m578-m580
In the title complex, [Ni(C21H14Br2N2O2)], the NiII atom is coordinated by the two imine N and two phenolate O atoms of the Schiff base ligand in a tetrahedrally distorted square‐planar geometry. The Ni—N and Ni—O distances are within the ranges expected for Ni–Schiff base derivatives. Intermolecular C—H⋯O hydrogen bonds link the molecules into centrosymmetric dimers, forming (12) (A) and (10) (B) rings. These dimers combine to form a supramolecular ABAB… aggregate which propagates along the [100] direction. 相似文献
19.
Anna Gasowska 《无机化学与普通化学杂志》2006,632(14):2281-2287
Interactions between the nucleotides: adenosine‐5′‐diphosphate (ADP) and adenosine‐5′‐triphosphate (ATP) with NiII and CoII ions, as well as with spermine (Spm) and 1,11‐diamine‐4,8‐diazaundecane (3,3,3‐tet) are the subject of this study. Composition and stability constants of mixed complexes thus formed have been determined on the basis of the potentiometric measurements, whereas interaction centres in ligands have been identified by VIS and NMR spectral parameter analysis. Mixed tetraprotonated complexes with NiII, i.e. Ni(ADP)H4(Spm), Ni(ATP)H4(Spm), Ni(ADP)H4(3,3,3‐tet) and Ni(ATP)H4(333‐tet), are identified as ML·······L′ type adducts, in which the main coordination centre is the nucleotide nitrogen N(1) or N(7) donor atom, and the fully protonated polyamine is engaged in noncovalent interactions with nucleotide phosphate group oxygen atoms. Ni(ADP)H2(Spm), Ni(ATP)H2(Spm), Ni(ADP)H2(3,3,3‐tet) and Ni(ATP)H2(3,3,3‐tet) complexes represent the {N3} coordination type In diprotonated mixed complexes of NiII with spermine are weak noncovalent interligand interactions, providing an additional stabilising effect. Formation of ML·······L′ type molecular complexes has been observed in systems with CoII: Co(ADP)H4(Spm), Co(ATP)H4(Spm), Co(ADP)H4(3,3,3‐tet) and Co(ATP)H4(3,3,3‐tet), in which the N(7) atom and oxygen atoms of the phosphate group are involved in coordination and the fully protonated polyamine is engaged in noncovalent interactions with the nucleotide N(1). 相似文献
20.
Wen‐Na Zhao Jian‐Wei Zou Qing‐Shen Yu 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(9):m443-m444
The title one‐dimensional chain nickel(II)–disulfide complex, [Ni(C14H8O4S2)(C5H5N)2(H2O)]n, has each NiII cation coordinated by two N atoms from two pyridine ligands, three carboxylate O atoms from two different dithiodibenzoate ligands and one O atom from a coordinated water molecule, in a distorted octahedral coordination geometry. Each dithiodibenzoate ion links two NiII cations through its carboxylate O atoms, making the structure polymeric. Hydrogen‐bond interactions between two shoulder‐to‐shoulder chains lead to the formation of a ladder‐like structure. 相似文献