Abstract:
Reaction of [Ru(H)2(CO)(PPh3)3] 1 with an equimolar amount of pyrrole-2-carboxylic acid (H2L1) leads to the homoleptic chelate derivative k2(O,O)-[RuH(CO)(HL1)(PPh3)2] 2. Prolonged acetonitrile refluxing promotes an unusual k2(O,O)- → k2(N,O)- dynamic chelate conversion, forming a neutral, stable, air- and moisture- insensitive, solvento-species k2(N,O)-[Ru(MeCN)(CO)(L1)(PPh3)2] 3. Analogously, reaction of 1 with the pyrrole-2-carboxyaldehyde (HL2) affords k2(N,O)-[RuH(CO)(HL2)(PPh3)2] 4, 5, as a couple of functional isomers. Optimized reaction conditions such as temperature and solvent polarity allow the isolation of dominant configurations. Structure 5 is a pyrrolide Ru-carbaldehyde, obtained from cyclization of the pendant CHO function, whereas species 4 can be viewed as an ethanoyl-conjugated Ru-pyrrole. Derivatives 3-5 were characterized by single crystal X-ray diffraction, ESI-Ms, IR, and NMR spectroscopy, indicating distinct features for the Ru-bonded pyrrolyl groups. DFT computational results, coplanarity, bond equalization, and electron delocalization along the fused five-membered rings support aromatic features. In accordance with the antisymbiotic trans-influence, both the isolated isomers 4 and 5 disclose CO ligands opposite to N- or O-anionic groups. The quantitative Mayer bond order evidences a stabilizing backbonding effect. Antibacterial and antifungal trials on Gram-positive (Staphylococcus aureus), Gram-negative (Escherichia coli), and Candida albicans were further carried out.
摘要:
[Ru(H)2(CO)(PPh3)3]1与等摩尔量的吡咯-2-羧酸(H2L1)的反应产生了同配位螯合物衍生物k2(O,O)-[RuH(CO)(HL1)(PPh3)2]2。长时间的乙腈回流促进了不寻常的k2(O,O)-→k2(N,O)-动态螯合物转化,形成一个中立的,稳定,对空气和水分不敏感,solvento种k2(N,O)-[Ru(MeCN)(CO)(L1)(PPh3)2]3。类似地,1与吡咯-2-甲醛(HL2)反应得到k2(N,O)-[RuH(CO)(HL2)(PPh3)2]4,5,作为一对功能异构体。优化的反应条件如温度和溶剂极性允许分离主要构型。结构5是吡咯Ru-甲醛,通过悬垂的CHO功能的环化获得,而物种4可以被视为乙酰基共轭的Ru-吡咯。衍生物3-5通过单晶X射线衍射表征,ESI-Ms,IR,和核磁共振波谱,表明Ru键合的吡咯基具有不同的特征。DFT计算结果,共面性,债券均衡,电子沿着稠合五元环的离域支持芳族特征。根据反共生的反式影响,分离的异构体4和5都公开了与N-或O-阴离子基团相反的CO配体。定量的Mayer键序证明了稳定的背键效应。革兰氏阳性(金黄色葡萄球菌)的抗菌和抗真菌试验,革兰氏阴性(大肠杆菌),和白色念珠菌进一步进行。