McClintock Lisa F, Cavigliasso Germán, Stranger Robert, Blackman Allan G
Department of Chemistry, University of Otago, P.O. Box 56, Dunedin, New Zealand.
Dalton Trans. 2008 Oct 7(37):4984-92. doi: 10.1039/b806981f. Epub 2008 Jul 31.
The syntheses and X-ray structures of [Co(Me-tpa)O2COZnCl3], [Co(pmea)O2COZnCl3].H2O Co(trpyn)O2COZn(OH2)4OCO2Co(trpyn)2.H2O, [Co(trpyn)(O2COH)]ZnCl(4).3H2O and [Co(trpyn)(O2CO)]ClO4 are reported (Me-tpa=[(6-methyl-2-pyridyl)methyl]bis(2-pyridylmethyl)amine, pmea=bis(2-pyridylmethyl)-2-(2-pyridylethyl)amine, trpyn=tris(2-(1-pyrazolyl)ethyl)amine). The chelated bicarbonate complex [Co(trpyn)(O2COH)]ZnCl(4).3H2O is isolated as a crystalline solid from an acidic solution of the parent carbonate [Co(trpyn)(O2CO)]ClO4, and X-ray structural analysis shows that lengthening of the C=Oexo bond and shortening of the C-Oendo bond accompanies protonation. The bimetallic complex [Co(Me-tpa)O2COZnCl3] results from the unexpected coordination of ZnCl3- to the exo O atom of a chelated carbonate ligand. This complex is obtained from both acidic and neutral solutions in which [Zn2+]=1.0 M, while the structurally similar complex [Co(pmea)O2COZnCl3].H2O is isolated from an analogous neutral solution. The trimetallic complex Co(trpyn)O2COZn(OH2)4OCO2Co(trpyn)2.H2O crystallises on prolonged standing of [Co(trpyn)(O2CO)]ClO4 in a neutral solution having [Zn2+]=1.0 M. The Zn-O bond lengths in all three complexes are indicative of bonds of significant strength. DFT calculations show that the nature of the bonding interaction between the Co(III) ion and the endo O atoms of the carbonate ligand remain essentially unaffected by coordination of Zn2+ to the exo O atom. They also show that such coordination of Zn2+ decreases the C-Oexo bond order.
报道了[Co(Me-tpa)O₂COZnCl₃]、[Co(pmea)O₂COZnCl₃]·H₂O、Co(trpyn)O₂COZn(OH₂)₄OCO₂Co(trpyn)₂·H₂O、[Co(trpyn)(O₂COH)]ZnCl₄·3H₂O和[Co(trpyn)(O₂CO)]ClO₄的合成及X射线结构（Me-tpa = [(6-甲基-2-吡啶基)甲基]双(2-吡啶基甲基)胺，pmea = 双(2-吡啶基甲基)-2-(2-吡啶基乙基)胺，trpyn = 三(2-(1-吡唑基)乙基)胺）。螯合的碳酸氢盐配合物[Co(trpyn)(O₂COH)]ZnCl₄·3H₂O是从母体碳酸盐[Co(trpyn)(O₂CO)]ClO₄的酸性溶液中分离得到的结晶固体，X射线结构分析表明，质子化伴随着C=O外键的延长和C-O内键的缩短。双金属配合物[Co(Me-tpa)O₂COZnCl₃]是由ZnCl₃⁻意外地与螯合碳酸盐配体的外O原子配位形成的。该配合物可从[Zn²⁺]=1.0 M的酸性和中性溶液中获得，而结构相似的配合物[Co(pmea)O₂COZnCl₃]·H₂O是从类似的中性溶液中分离得到的。三金属配合物Co(trpyn)O₂COZn(OH₂)₄OCO₂Co(trpyn)₂·H₂O是在[Co(trpyn)(O₂CO)]ClO₄在[Zn²⁺]=1.0 M的中性溶液中长时间放置后结晶得到的。所有三种配合物中的Zn-O键长都表明键具有显著强度。密度泛函理论计算表明，Co(III)离子与碳酸盐配体内O原子之间的键合相互作用的性质基本上不受Zn²⁺与外O原子配位的影响。计算还表明，Zn²⁺的这种配位降低了C-O外键级。
