摘要
分别通过Mo≡Mo→Mo≡Mo的双电子氧化还原反应及由单核Mo(Ⅲ)配合物经硫脲[SC(NH_2)_2]桥联的方法合成具有三重Mo—Mo键的配合物Mo_2Cl_5[SC(NH_2)_2]_3·2H_O.该配合物晶体的结晶学参数为:三斜晶系,PI空间群,.晶胞中2个结晶学独立的分子中Mo—Mo键长分别为2.439(1)A和2.443(1)A.配合物的S-C键削弱了桥S原子参与d-p相互作用的程度,有利于形成较强的Mo≡Mo键,其d-d分子轨道的电子构型是ν~2(π+δ)~4.
The complex Mo2C16[SC(NH2)2]3. 2H2O was synthesized by the redox reaction of Mo=Mo →Mo = Mo, and by that of a mononuclear Mo ( Ⅲ) complex (NH4)2MoCl3(H2O) with thiourea SC (NH2)2. The crystal of the complexis crystalized in triclinic P1 space group. The parameters of the link cell are a = 8. 747(1) A , 6=9. 224(1) A. c=13. 733(2) A ,α=103. 35(1)°, β=94. 02(1)°, γ= 112. 40(1)°, V=981. 3A3,Z=2, Dc = 2. 359 g . cm-3 and the final R=0. 032, R=0. 037. for 4201 reflections with 1≥3σ(1). The coordination geometry of the two Mo(Ⅲ ) atoms is a distorted octahedron Cl3MoS3,in which the three S atoms are shared between the two Mo atoms. Of the two crvstallographically independent molecules, the Mo-Mo bond lengths are 2. 439(1 ) A ,2. 443(1) A respectively and the S-C distances about 0. 06 A longer than that in thiourea molecule because of the bridge coordination of S atoms and a certain d-π back bonding in the complex. The S-C bonds weaken the d-p interactions between the Mo atoms and the S atoms, and so strengthen the Mo-Mo bonds. The electronic configuration of d-d molecular orbitals in the complex is σ2 (π+ δ)4, indicated by EHMO calculation.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
1991年第1期6-10,共5页
Chemical Journal of Chinese Universities
基金
国家自然科学基金
关键词
Mo-Mo键
配合物
三重键
晶体结构
Thiourea, Triple Mo-Mo bond, d-p interaction, Crystal structure, Electronic configuration
