设计了用于金属介导的碱基对的基于腙的新核苷家族。人工核碱基是 papy 配体的衍生物(papy = pyridinecarboxaldehyde-2'-pyridylhydrazone)。通过分别用呋喃和噻吩替换纸糊中的侧基吡啶部分,获得了具有 N, N, N-, N, N, O- 和 N, N, S-供体位点的三齿核苷。由于仅报道了少数具有悬垂呋喃配体的过渡金属配合物,因此合成了 N、N、O 供体核苷的模型核碱基。报道了其 Cu2+、Ni2+ 和 Co2+ 配合物的分子结构。在所有配合物中,仅观察到弱的 M-O(呋喃) 键合。Co2+ 复合体显示出五边形双锥体配位排列。一般来说,
Manganese-Catalyzed Direct Olefination of Methyl-Substituted Heteroarenes with Primary Alcohols
作者:Milan K. Barman、Satyadeep Waiba、Biplab Maji
DOI:10.1002/anie.201804729
日期:2018.7.16
Herein, we present the first catalyticdirectolefination of methyl‐substituted heteroarenes with primary alcohols through an acceptorless dehydrogenative coupling. The reaction is catalyzed by a complex of the earth‐abundant transition metal manganese that is stabilized by a bench‐stable NNN pincer ligand derived from 2‐hydrazinylpyridine. The reaction is environmentally benign, producing only hydrogen
fac-Specific syntheses of homochiral [Fe(NN′)3]2+ complexes (NN′ = pyridine keto-hydrazone); origins of the stereoselectivity
作者:Cynthia Paul Sebli、Suzanne E. Howson、Guy J. Clarkson、Peter Scott
DOI:10.1039/c000815j
日期:——
The 2-pyridinehydrazones (from condensation of pyridine-2-carbaldehyde and hydrazines) have previously been noted to have poor ligating ability as a result of a sterically demanding planar conformation. Destabilisation of this conformation is achieved through simple use of the ketohydrazones, and as a result the diamagnetic chiral tris-bidentate diimine complexes fac-[FeL3]2+ are readily isolated. In the solid state, inter-ligand ÏâÏ stacking and complex/counter-ion H-bonding are apparent, and these features persist in solution according to dynamic NMR spectra, which also indicate extremely high stereoselectivity for the fac isomers (>200â:â1). The compounds crystallise as conglomerates, and time-resolved CD spectra of non-racemic samples indicate a high degree of persistence of chirality (racemisation t1/2ca 77 min). Variations of solvent and counter-ion indicate that H-bonding is unimportant in determining the structure of the cation. The fac-selectivity arises in the induction of a chiral conformation in the coordinated ligand, and the fact that such non-planar ligands can only be accommodated about the Fe(II) centre if they all have the same absolute configuration. Adding a hydrazine N-methyl group increases the steric demand further, while retaining the novel non-planar conformation, and as a result paramagnetic chiral bis-bidentate complexes such as [FeL72(CH3CN)2]2+ are readily available.
2 吡啶肼(由吡啶-2-甲醛和肼缩合而成)由于具有立体要求较高的平面构象,因此连接能力较差。通过简单地使用酮酰肼就可以破坏这种构象的稳定性,因此很容易分离出二磁性手性三公头二亚胺配合物 fac-[FeL3]2+。在固态下,配体间的ÏâÏ堆叠和络合物/反离子间的氢键作用十分明显,根据动态核磁共振光谱,这些特征在溶液中也会持续存在,这也表明 fac 异构体具有极高的立体选择性(>200â:â1)。化合物结晶为团聚体,非外消旋样品的时间分辨 CD 光谱表明手性具有高度的持久性(外消旋化 t1/2ca 77 分钟)。溶剂和反离子的变化表明,氢键在决定阳离子结构方面并不重要。面选择性是由于配位配体的手性构象的诱导作用,而这种非平面配体只有在绝对构型相同的情况下才能被容纳在 Fe(II) 中心周围。添加肼 N-甲基会进一步增加立体需求,同时保留新颖的非平面构象,因此顺磁手性双同位配合物(如 [FeL72(CH3CN)2]2+)很容易获得。
Co(II) and Ni(II) complexes of linear tridentate nitrogenous ligands
作者:B. Chiswell、D.S. Litster
DOI:10.1016/s0020-1693(00)89623-1
日期:1978.1
mono-ligand complexes of some linear tridentate nitrogenous ligands with nickel(II) and cobalt(II) salts are described. The compounds of formula [Ni- (ligand)X2] (X = Cl, Br, I or NCS) appear to be bridged octahedral compounds on the basis of electronic and infrared spectral measurements. On the other hand, spectral results indicate that the similar compounds of cobalt(II), are monomeric five-coordinate species
Structurally related hydrazone-based metal complexes with different antitumor activities variably induce apoptotic cell death
作者:Dominik A. Megger、Kristin Rosowski、Christian Radunsky、Jutta Kösters、Barbara Sitek、Jens Müller
DOI:10.1039/c6dt04613d
日期:——
Three new metal complexes bearing a tridentate hydrazone-based ligand were synthesized and structurally characterized. Depending on the metal ion, the complexes show remarkably different antitumor activities.
Compounds having a structure according to Formula (I):
1
are effective in a method of increasing erythroproietin and vascularization of tissue in a subject in need thereof.