New Route to Polynuclear Ni(II) and Cu(II) Complexes with Bridging Oxime Groups That Are Inaccessible by Conventional Preparations

Abstract

A series of new polynuclear complexes of divalent Ni and Cu with 2-cyano-2-oximino-acetic acid (later AACO2-) were obtained as the result of the ligand modification reaction in the process of complexation, using 2-cyano-2-oximino-acetates such as methyl- (later as MeCO), and ethyl- (as ECO later on). Synthesized compounds were characterized by spectroscopic methods, thermal analysis, magnetochemistry, and X-ray crystallography. Crystal data revealed the formation of the dimeric [Ni­(AACO)­(H2O)3]2­·H2O (1), trimeric K2[Ni3(AACO)4­(H2O)4]­·4H2O (2), and K2[Cu3(AACO)4­(H2O)4]·4H2O (3) complexes, with bridging NO-groups cyanoxime dianions. In the latter two compounds, the AACO2– anions adopt cis-arrangements around metal centers. One mononuclear complex of K2[Cu­(AACO)2­(H2O)]­·2H2O (4) composition was isolated and characterized as well, where the cyanoxime forms the trans-complex 4. There is moderate-to-strong antiferromagnetic coupling between metal centers in polynuclear complexes. Data of thermal analysis studies revealed high-energy properties for dehydrated complexes 3 and 4, which violently decompose at ∼200 °C. These compounds may be viewed as room temperature completely safe, but heat-triggered actuators, because of their pronounced mechanical action upon leaving the system (crucible). Final products of thermal decomposition are Ni and NiO for 1, and the mixture of NiO and K2O for 2, with metallic copper for 3 and 4.

2‐substituted tricyclic oxazolo[5,4‐d]pyrimidine library: Design, synthesis, and cytotoxicity activity

“…In this way, several 2‐substituted ethyl 5‐amino‐oxazole‐4‐carboxylate synthones ( 5a – aw ) were synthesized via a four‐step procedure. First, ethyl 2‐cyano‐2‐(hydroxyimino)acetate ( 2 ) was prepared from the ethyl cyanoacetate ( 1 ) using sodium nitrite solution and 85% orthophosphoric acid [38]. Reduction of this oxime compound to amine ( 3 ) was performed using Na 2 S 2 O 4 in a NaHCO 3 solution [39].…”

Building Oxime-Ni2+ Complex on Polymeric Carbon Nitride: Molecular-Level Design of Highly Efficient Hydrogen Generation Photocatalysts

“…Herein, in this work, we modified the PCN surface with oxime functional groups (Scheme 1) that can effectively capture Ni 2+ through strong coordination interactions. [24][25][26] As a result, the covalently grafted oxime-Ni 2+ complex structures are enriched and uniformly distributed on PCN surfaces, and serve as active catalytic sites for HER by using photoelectrons from excited PCN.…”

Design, synthesis, in vitro evaluation of a new pyrrolo[1,2‐a]thiazolo[5,4‐d]pyrimidinone derivatives as cholinesterase inhibitors against Alzheimer's disease

“…The target compounds were prepared through seven steps as outlined in Scheme 1. First, ethyl 2‐cyano‐2‐(hydroxyimino)acetate ( A ) was prepared from the ethyl cyanoacetate using sodium nitrite solution and 85% orthophosphoric acid [28]. Reduction of this oxime compound to amine B was performed using Na 2 S 2 O 4 in a NaHCO 3 solution [29].…”