摘要
用参数化经验公式,从已知晶体结构的无水双邻羟基苄胺铜(Ⅱ)[Cu(o-OC_6H_4CH_2NH_2)_2, 1]的EXAFS数据中分离出振幅和相移,拟合另一已知晶体结构的水合双邻羟基苄胺铜(Ⅱ){[Cu(o-OC_6H_4CH_2NH_2)_2·H_2O]·1/2H_2O,2}的结构参数并进行检验后,代入未知结构的水合双邻羟基苄氨乙酸铜(Ⅱ)[Cu(o-HOC_6H_4CH_2NHCH_2CO_2)_2·H_2O,3]中进行曲线拟合,得到配位原子、键长和配位数等结构信息。结合红外光谱,推断标题化合物中,Cu(Ⅱ)与两个苄基氮和两个羧基氧形成一个平面四边形的配位结构。 Cu—O_(羧基)健长2.00A,Cu-N键长1.90A,另有一个较远的配住水分子,Cu—O_水距离2.95A。配体上的酚基氧没有与Cu(Ⅱ)配合。因此,邻羟基苄氨乙酸(HBG)与Cu(Ⅱ)配位时表现为二啮形式。
EXAFS measurements were performed on the K-edge for bis (o-hydroxybenzylamine)
copper(Ⅱ) (1), bis(o-hydroxybenzylamine) copper (Ⅱ) hydrate (2) and bis(N-o-
hydroxybenzylglycine) copper (Ⅱ) hydrate (3) on a X-ray spectrometer in transmission
mode. The crystal structures of the first two compounds are known and used as the model
and reference compound respectively. Parameterized amplitude and phase shift were
curve fitted from the Fourier filtering data of compound 1, and transferred to deduce
the structural parameters of compound 2 for certification. By curve fitting the EXAFS
of compound 3 with the certified amplitude and phase shift function, the coordination
structural information of bond lengths, coordination numbers and the type of
coordination atoms were obtained. Combined with IR spectroscopy and ionic conductivity
studies, the conclusion can be inferred that Cu (Ⅱ) in the title compound is linked with
two benzyl nitrogen atoms, two carbexylate oxygen atoms, and has a coordination of
square-planar, wheroin the Cu--O (carboxylate oxygen) bond length is of 2.00A, Cu--N
of 1.99 A. There is another oxygen atom located 2.95A away from the central copper.
The phenol oxygen atom in 3 is not coordinated with Cu(Ⅱ), therefore, here HBG
behaves as a bi dentate ligand.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
1989年第1期37-41,共5页
Acta Chimica Sinica
基金
国家自然科学基金
