Heterointerface of all-alkynyl-protected Au_(28) nanoclusters anchored on NiFe-LDHs boosts oxygen evolution reaction:a case to unravel ligand effect

Ultrasmall Au nanoclusters have been proven to effectively enhance the catalytic performance of NiFe layered double hydroxides(NiFe-LDHs)toward oxygen evolution reaction(OER),yet the surface ligand effect of the Au nanoclusters still remains elusive.Herein,a systematic study is reported to examine the OER performance of NiFe-LDHs supported atom-precise all alkynyl-protected[Au_(28)(~tBuC≡C)17]~-nanoclusters(Au_(28)-Alkynyl in short)and thiolate-protected Au_(28)(TBBT)_(20)(TBBT=4-tert-butylbenzene thiol)counterp arts(Au_(28)-Thiolate in short).The Au_(28)-Alkynyl cluster has characteristic absorbance feature,and its composition is verified by mass spectrometry.It possesses a drastically different structure from the reported mixed ligand protected Au_(28)nanoclusters.Interestingly,the NiFe-LDHs loaded with Au_(28)-Alkynyl exhibited a superior OER performance than the sample loaded with Au28-Thiolate under the same conditions,evidenced by a smaller overpotential of 205 mV at the current density of 10 mA·cm^(-2)and a lower Tafel slope value of 41.0 mV·dec^(-1)in 1 mol·L^(-1)KOH.Such excellent performance is attributed to the interfaces created between the NiFe-LDHs and the Au nanoclusters,as density functional theory calculations reveal that more significant charge transfer occurs in Au_(28)-Alkynyl/NiFeLDHs catalyst,and more importantly,the energy barrier of the potential-determining step in the OER process for Au28-Alkynyl/NiFe-LDHs is much lower than that of Au28-Thiolate/NiFe-LDHs hence favors the electrocatalytic reaction.

炔基配体对2,6-双(N-乙基苯并咪唑)吡啶炔基铂(Ⅱ)配合物与G-四链体作用及抗癌活性的影响(英文)

合成了三种2,6-双(N-乙基苯并咪唑)吡啶炔基铂(Ⅱ)配合物(2-4),其中配合物2的炔基配体为抗癌药物埃罗替尼.利用紫外-可见(UV-Vis)吸收光谱,圆二色(CD)光谱,荧光共振能量转移(FRET)等方法研究了铂(Ⅱ)配合物与人体端粒(Hetelo)和c-myc原癌基因(c-myc)G-四链体的相互作用.实验结果表明,所合成的铂配合物与G-四链体具有较强的相互作用(K_a>10~6L·mol^(-1)),在无碱金属离子存在条件下能诱导G-四链体的形成.含苯乙炔基团的配合物2、3能使c-myc G-四链体的熔解温度上升24℃以上,而含丙炔基团的铂配合物4仅使c-myc G-四链体的熔解温度升高9.0℃,表明炔基结构对铂(Ⅱ)配合物与G-四连体的作用有较大影响.配合物2对人肺癌细胞A549的细胞毒性明显高于埃罗替尼及其他两种配合物3、4.

Atomically precise alkynyl-protected Ag_(20)Cu_(12)nanocluster:Structure analysis and electrocatalytic performance toward nitrate reduction for NH_(3)synthesis

Electrochemical nitrate reduction reaction(NtrRR)has been emerging as an appealing route for both water treatment and NH_(3)synthesis.Herein,we report the structure analysis and electrocatalytic performance of a novel homoleptic alkynyl-protected Ag_(20)Cu_(12)nanocluster(Ag_(20)Cu_(12)in short)with atomic precision,which has eight free electrons and displays characteristic absorbance feature.Single crystal X-ray diffraction(SC-XRD)discloses that,it adopts a Ag_(14)kernel capped by three Ag_(2)Cu_(4)(C≡CArF)_(8)metal–ligand binding motifs in the outer shell.Ag_(20)Cu_(12)exhibited excellent catalytic performance toward NtrRR,as manifested by the superior NH_(3)Faradaic efficiency(FE,84.6%)and yield rate(0.138 mmol·h^(−1)·mg−1)than the homoleptic alkynyl-protected Ag_(32)nanoclusters.Additionally,it demonstrates good catalytic recycling capability.Density functional theory(DFT)calculations revealed that,the de-ligated Ag_(20)Cu_(12)cluster can expose the available AgCu bimetallic sites as the efficient active sites for NH_(3)formation.In particular,the participation of Cu sites greatly facilitates the initial capture of NO_(3)−and simultaneously promotes the selectivity of the final product.This study discovers a novel homoleptic alkynyl-protected AgCu superatom,and offers a great example to elucidate the structure–performance relationship of bimetallic catalyst for NtrRR and other multiple protons/electrons coupled electrocatalytic reactions.

平面手性二茂铁N,O-配体催化苯乙炔对醛的不对称加成反应(英文)

以手性N ,N 二甲基二茂铁乙胺为原料,采用文献报道的方法合成了两个具有平面手性的二茂铁N ,O 配体,并将其应用到苯乙炔对醛的不对称加成反应之中,考察了不同溶剂和不同底物的影响.结果表明,配体(R) 1 [(α二甲胺基)乙基] (S) 2 (二苯基羟基甲基)二茂铁催化剂对该类反应具有较高的催化活性及较好的手性诱导能力,乙醚是该体系最好的溶剂,苯甲醛为底物时可获得高达82

Homoleptic alkynyl-protected Ag_(32 )nanocluster with atomic precision: Probing the ligand effect toward CO_(2) electroreduction and 4-nitrophenol reduction

We report a superatomic homoleptic alkynyl-protected Ag_(32)L_(24)(L=3,5-bis(trifluoromethylbenzene)acetylide,Ag_(32) for short)nanocluster with atomic precision,which possesses eight free electrons.Ag_(32) is formed by an Ag17 core with C3 symmetry and the remaining 15 Ag atoms bond to each other and coordinate with the 24 surface ligands.When applied as electrocatalyst for CO_(2) reduction reaction(CO_(2)RR),Ag_(32) exhibited the highest Faradaic efficiency(FE)of CO up to 96.44%at−0.8 V with hydrogen evolution being significantly suppressed in a wide potential range,meanwhile it has a reaction rate constant of 0.242 min−1 at room temperature and an activation energy of 45.21 kJ·mol−1 in catalyzing the reduction of 4-nitrophenol,both markedly superior than the thiolate and phosphine ligand co-protected Ag_(32) nanocluster.Such strong ligand effect was further understood by density functional theory(DFT)calculations,as it revealed that,one single ligand stripping off from the intact cluster can create the undercoordinated Ag atom as the catalytically active site for both clusters,but alkynyl-protected Ag_(32) nanocluster possesses a smaller energy barrier for forming the key*COOH intermediate in CO_(2)RR,and favors the adsorption of 4-nitrophenol.This study not only discovers a new member of homoleptic alkynyl-protected Ag nanocluster,but also highlights the great potentials of employing alkynyl-protected Ag nanoclusters as bifunctional catalysts toward various reactions.

新型C_2对称的双氨基醇配体对芳香醛的不对称炔基化加成

目的:设计和合成新的手性配体,研究苯乙炔对苯甲醛的不对称加成反应,期待发现较好的手性配体。方法:将制备得到新颖的C2对称的双氨基醇(其结构类似于Salens′)作为手性配体,用丁基锂作为金属试剂,对加成反应进行了研究。结果与结论:合成了4种新颖手性配体(4～7),但仅获得一般的对映体选择性,所使用配体构型的转变会导致产物醇的构型转变。

炔基膦金(Ⅰ)配合物抗肿瘤活性研究进展

顺铂抗肿瘤活性的发现促使人们寻找新的金属配合物作为潜在的抗癌药物,其中金配合物作为抗癌药物的研究受到广泛关注。炔基膦金(Ⅰ)配合物引起的明显抗增殖作用源于其新的作用机制,同时由于其独特的化学性质和相关的配位方式,炔基膦金(Ⅰ)配合物作为未来以金为基础的抗癌药物成为该领域研究的热点之一。综述近年来炔基膦金(Ⅰ)配合物的抗肿瘤活性研究进展,包括炔基膦金(Ⅰ)配合物的结构特点、优化设计、协同药效和诊疗活性等,以期为相关研究和应用提供参考。