通过相应的水杨基苯并恶唑配体与1或0.5当量的AlMe 3的反应成功合成了两个系列的四配位铝(1a–9a)和五配位铝(1b–9b)配合物。合成的铝配合物通过1 H和13 C NMR光谱和元素分析进行表征。使用单晶X射线衍射确定配合物7a和1b的固态结构。加入1当量的苄醇后,所有络合物都是外消旋丙交酯(ROP)开环聚合(ROP)的有效引发剂(rac -LA)和ε-己内酯(ε-CL)。聚合反应在对分子量和分子量分布的良好控制下进行。在永生聚合条件下,所有四配位的铝配合物(1b–9b)均表现出活性聚合,所获得的分子量与单体/苯甲醇之比成比例,并且PDI较窄。动力学研究表明,所有配合物介导的rac -LA和ε-CL聚合都是单体中的一级反应。讨论了配体结构和配位几何形状对催化活性和立体选择性的影响。配合物4b(P m= 0.75),5b(P m = 0.74)和9b(P m = 0.74)。
Highly efficient AgNO<sub>3</sub>
-catalyzed approach to 2-(benzo[<i>d</i>
]azol-2-yl)phenols from salicylaldehydes with 2-aminothiophenol, 2-aminophenol and benzene-1,2-diamine
derivatives in good to excellent yields (63–98%) is described. The reaction proceeds via condensation/intramolecular nucleophilic addition/oxidation process between substituted salicylaldehydes and 2‐aminothiophenol, 2‐aminophenol or benzene‐1,2‐diamine under mild reaction conditions. Notably, this reaction utilizes cheap AgNO3 as a readily available and low‐cost benign oxidant at low catalyst loadings with
描述了一种新的,便捷有效的AgNO 3催化策略,用于制备2-(苯并[ d ] azol-2-基)苯酚衍生物,产率高至优异(63-98%)。反应在温和的反应条件下通过取代的水杨醛与2-氨基硫酚,2-氨基酚或苯1,2-二胺之间的缩合/分子内亲核加成/氧化过程进行。值得注意的是,该反应利用廉价的AgNO 3作为易于获得的低成本良性氧化剂,催化剂负载低,具有出色的官能团耐受性。
Synthesis of luminescent BPh2-coordinated 2-(2′-hydroxyphenyl)benzoxazole (HBO)
Triphenylborane (BPh3) has been successfully coordinated to five Ï-conjugated aromatic systems containing a Nâ§O bidentate 2-(2â²-hydroxyphenyl)benzoxazole (HBO) ligand. Complexes 6â8 are directly substituted on the phenolic side of the HBO core while the structure of derivatives 9â10 includes a 4-dibutylaminophenyl module linked through an ethynyl fragment, at position 4 or 5. The crystal structure of complexes 8 and 10 reveals different solid-state molecular packing depending on the substitution, a herringbone molecular packing being observed for complex 8 while the dibutylamino fragment present in complex 10 is in favour of a lamellar structure. The optical properties are highly dependent on the nature and the position of substituents. Solvatochromic charge-transfer emissions are observed for substitution at position 3 or 5 while singlet emission is favoured when position 4 is functionalized. Solid-state fluorescence reveals that complex 8 possesses red-shifted emission when dispersed in a KBr matrix.
Nb and Ta benzotriazole or benzoxazole phenoxide complexes as catalysts for the ring-opening polymerization of glycidol to synthesize hyperbranched polyglycerols
9a) niobium (Nb) and tantalum (Ta) complexes of benzotriazole or benzoxazole phenoxide pro-ligands bearing different substituents at the ortho and para positions of the phenol rings were synthesized and characterized. The reaction of NbCl5 or TaCl5 with one equivalent of benzotriazole or benzoxazole phenoxide pro-ligands (L1H–L6H) in dry toluene or chloroform produced the corresponding chloride (1a–6a
Fluorescent phenoxy benzoxazole complexes of zirconium and hafnium: synthesis, structure and photo-physical behaviour
作者:Lisa Kuhlmann、Rafael Methling、Jasmin Simon、Beate Neumann、Hans-Georg Stammler、Cristian A. Strassert、Norbert W. Mitzel
DOI:10.1039/c8dt01757c
日期:——
A series of ten heteroleptic and homoleptic mononuclear Zr(IV) and Hf(IV) complexes bearing differently substituted phenoxy-benzoxazole ligands was synthesised. The complexes were characterised by 1H and 13C1H} NMR spectroscopy as well as by elemental analyses and X-ray diffraction experiments. The molecular structures show octahedral or tetragonal-antiprismatic coordination motifs at the metal atom
合成了十个带有不同取代的苯氧基-苯并恶唑配体的杂合和纯合的单核Zr(IV)和Hf(IV)配合物。配合物的特征是1 H和13 C 11 H NMR光谱以及元素分析和X射线衍射实验。分子结构在金属原子上显示八面体或四边形-反棱柱形配位基序。晶体堆积模式取决于配体的取代。固态的分子间相互作用受弱的π-π相互作用控制,并且还取决于配体的结构。光物理研究表明,所有十种络合物均显示出以配体为中心的荧光,并且在电磁波谱的蓝色区域具有最大的发射。
Fluorescent Heteroleptic Zirconium and Hafnium Complexes
作者:Lisa Kuhlmann、Rafael Methling、Jasmin Simon、Beate Neumann、Hans-Georg Stammler、Cristian A. Strassert、Norbert W. Mitzel
DOI:10.1002/zaac.201800312
日期:2018.10.2
Five new heteroleptic zirconium and hafnium complexes were synthesized. The complexes carry chloro ligands as well as differently substituted phenoxy benzoxazole ligands [HL1 = 2‐(2′‐hydroxyphenyl)benzoxazole, HL2 = 2‐(2′‐hydroxynaphthyl)benzoxa‐zole, HL3 = 2‐(2′‐hydroxy‐3′,5′‐di‐tert‐butylphenyl)benzoxazole]. They were characterized by 1H and 13C1H} NMR spectroscopy as well as by elemental analyses
合成了五种新的杂锆和and配合物。配合物带有氯配体以及不同取代的苯氧基苯并恶唑配体[ HL1 = 2-(2'-羟基苯基)苯并恶唑,HL2 = 2-(2'-羟基萘基)苯并恶唑,HL3 = 2-(2'-羟基- 3',5'-二叔丁基苯基)苯并恶唑]。它们的特征在于1 H和13 C 1 H} NMR光谱以及元素分析和X射线衍射实验。晶体中的分子结构显示出扭曲的八面体或加盖的三角棱柱配位球。影响堆积模式的分子间相互作用主要是H ···Cl接触。对于temperature络合物[Cl 2 Hf(L3)2 ],使用温度依赖性1 H NMR光谱检查了溶液中的动态行为。光物理数据表明,在所有情况下,荧光都是由短暂的激发态引起的,其发射最大值位于蓝色光谱区域。