Technische Universität Chemnitz, Fakultät für Naturwissenschaften, Strasse der Nationen 62, D-09111 Chemnitz, Germany.
Dalton Trans. 2013 Feb 7;42(5):1798-809. doi: 10.1039/c2dt32259e. Epub 2012 Nov 20.
The treatment of the diethyl ester of o-phenylenebis(oxamic acid) (opbaH(2)Et(2)) with 2/3 of an equivalent of MeNH(2) in MeOH does not result in the formation of the methyl ester of o-phenylene(N'-methyloxamide)(oxamic acid) (opooH(3)Me, 1) in pure state, as reported previously. The colourless crude material formed by this reaction was confirmed to be composed of 1 (89% content), the dimethyl ester of o-phenylenebis(oxamic acid) (opbaH(2)Me(2), 2, 6%), 1,4-dihydro-2,3-quinoxalinedione (3, 3%) and o-phenylenebis(N'-methyloxamide) (opboH(4)Me(2), 4, 1%), respectively. The identities of 1-4 have been verified by IR, (1)H and (13)C NMR spectroscopy as well as elemental analysis. In addition, the solid state structures of 1 and 2·2DMSO, respectively, were determined by single-crystal X-ray diffraction studies. Successive recrystallization of the crude material from MeOH and MeOH : THF (1 : 1), respectively, does not give pure 1, but a mixture of 1 and 2. It is shown further that out of this mixture pure bis(oxamato) complexes cannot be obtained, as previously reported. Instead, treatment of the mixture with Ni(II) or Cu(II) salts, followed by the addition of [(n)Bu(4)N]OH, results in the formation of two mixtures of (n)Bu(4)N[Ni(opba)] (5) and (n)Bu(4)N[Ni(opooMe)] (6) as well as (n)Bu(4)N[Cu(opba)] (7) and (n)Bu(4)N[Cu(opooMe)] (8), respectively. The simultaneous formation of 5/6 and 7/8, respectively, has been verified by crystallization of the obtained mixtures and X-ray diffraction studies of the obtained single crystals. Co-crystallization of mixtures of 5/6 (99 mass%) and 7/8 (1 mass%), respectively, results in the formation of single-crystals of diamagnetically diluted 7 in the host lattice of 5 (7@5) accompanied by single-crystal formation of diamagnetically diluted 8 in the host lattice of 6 (8@6), as verified by EPR spectroscopy. It is finally shown that the ethyl ester of o-phenylene(N'-methyloxamide)(oxamic acid) (opooH(3)Et, 9), a homologue of 1, can be obtained in pure state by the treatment of opbaH(2)Et(2) with 5/6 of an equivalent of MeNH(2) in EtOH.
用 2/3 当量的 MeNH2 在 MeOH 中处理邻苯二亚胺基双（氧代氨基）乙酸二乙酯（opbaH（2）Et（2）），不会得到邻苯二亚胺基-N-甲氧基双（氧代氨基）乙酸甲酯（opooH（3）Me，1）的纯态，这与之前的报道不同。该反应形成的无色粗产物被确认为由 1（89%含量）、邻苯二亚胺基双（氧代氨基）乙酸二甲酯（opbaH（2）Me（2），2，6%）、1,4-二氢-2,3-喹喔啉二酮（3，3%）和邻苯二亚胺基-N-甲氧基双（氧代氨基）乙酸（opboH（4）Me（2），4，1%）组成。通过红外光谱、（1）H 和（13）C NMR 光谱以及元素分析验证了 1-4 的身份。此外，通过单晶 X 射线衍射研究分别确定了 1 和 2·2DMSO 的固体结构。分别从 MeOH 和 MeOH:THF（1:1）中对粗产物进行连续重结晶，均不能得到纯 1，而是得到 1 和 2 的混合物。进一步表明，从该混合物中不能得到如前所述的纯双（氧代氨基）配合物。相反，用 Ni(II)或 Cu(II)盐处理混合物，然后加入[(n)Bu4N]OH，会导致形成两种混合物(n)Bu4N[Ni(opba)]（5）和(n)Bu4N[Ni(opooMe)]（6）以及(n)Bu4N[Cu(opba)]（7）和(n)Bu4N[Cu(opooMe)]（8）。通过获得的混合物的结晶和获得的单晶的 X 射线衍射研究，验证了 5/6 和 7/8 的同时形成。混合物 5/6（99 质量%）和 7/8（1 质量%）的共结晶导致 7 在 5 的主晶格中形成顺磁稀释单晶（7@5），同时 8 在 6 的主晶格中形成顺磁稀释单晶（8@6），这通过 EPR 光谱得到证实。最后表明，邻苯二亚胺基-N-甲氧基双（氧代氨基）乙酸乙酯（opooH（3）Et，9），1 的同系物，可以通过用 5/6 当量的 MeNH2 在 EtOH 中处理 opbaH（2）Et（2）来得到纯态。
