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作 者:黄辉胜[1] 张同来[1] 张建国[1] 王丽琼[1] 杨利[1] 乔小晶[1] 尚静[1]
机构地区:[1]北京理工大学爆炸科学与技术国家重点实验室,北京100081
出 处:《化学学报》2010年第4期289-293,共5页Acta Chimica Sinica
基 金:国家自然科学基金(No.20471008);北京理工大学爆炸科学与技术国家重点实验室开放基金(No.KFJJ08-06)资助项目
摘 要:对硝酸三碳酰肼合钴([Co(CHZ)3](NO3)2)、硝酸三碳酰肼合镍([Ni(CHZ)3](NO3)2)和硝酸二碳酰肼合铜([Cu(CHZ)2(NO3)2])进行密度泛函理论计算研究,获得其稳定分子的几何构型、电子结构、红外光谱以及热化学性质.研究结果表明,这三种配合物均表现出六配位八面体结构,而铜配合物中的硝酸根参与了配位.自然键轨道分析表明,配体和金属离子之间存在供体–受体相互作用,致使配位氨基N—H键上的成键轨道电子发生离域,进而导致氨基N—H键的电子占据数降低、键长增大、键级减小、伸缩振动频率红移,这与实测红外光谱变化规律很好地吻合.标题化合物的金属离子均为+1氧化态,金属–氮配位键都是共价键,而Cu—O配位键是离子键.通过计算求得理论反应热,预测这些配合物的合成均为放热反应;由生成热大小推测标题物的稳定性次序为[Ni(CHZ)3](NO3)2>[Co(CHZ)3](NO3)2>[Cu(CHZ)2(NO3)2],与实测热稳定性次序完全吻合.The molecular geometries,electronic structures,infrared spectra and thermochemical properties of cobalt and nickel tris(carbohydrazide) nitrates ([Co(CHZ)3](NO3)2 and [Ni(CHZ)3](NO3)2) as well as copper bis(carbohydrazide) nitrate ([Cu(CHZ)2(NO3)2]) were investigated by using the density functional theory. The obtained results show that these three complexes have a six-coordinated octahedron feature,and the nitrate ions are also coordinated with the copper cation. Detailed natural bond orbital (NBO) analyses indicate that the donor-acceptor interactions between the ligands and metal cations result in decreasing of occupancies of amino N—H bond orbitals,and subsequently,cause the stretching vibrations of amino groups to shift to lower wave number,which is in accord with the experimental result. The NBO analyses also show that all of the metal cations are almost in +1 oxidation state,and the M—N coordination bonds are covalent,but the Cu—O coordination bonds are predominantly ionic in nature. The calculated heats of reaction reveal that the synthesis reactions for the studied compounds are exothermic. Moreover,the computed heats of formation predict that the stabilities of the title compounds decrease in the order: [Ni(CHZ)3](NO3)2 [Co(CHZ)3](NO3)2[Cu(CHZ)2(NO3)2],which is in good agreement with the available experimental thermal stabilities.
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