SECONDARY BONDING .5. CRYSTAL AND MOLECULAR-STRUCTURES OF PHENYLIODINE(III) DIACETATE AND BIS-(DICHLOROACETATE)
SECONDARY BONDING .5. CRYSTAL AND MOLECULAR-STRUCTURES OF PHENYLIODINE(III) DIACETATE AND BIS-(DICHLOROACETATE)
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DOI：
10.1039/dt9790000854
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发表时间：
1979-01-01
期刊：
影响因子：
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通讯作者：
SAWYER, JF
中科院分区：
文献类型：
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作者：
ALCOCK, NW;COUNTRYMAN, RM;SAWYER, JF
标题化合物（1）和（2）的晶体结构分别在-60 ℃下用重原子法由衍射仪数据测定。（1）晶体为正交晶系，空间群Pnn 2，晶胞参数a= 15.693（3），B= 8.477（2），c= 8.762（2）nm，Z= 4，R= 0.021。（2）晶体属三斜晶系，空间群为P，a= 10.462（3），B= 4.870（2），c= 15.445（5）°，α= 101.03（3），β= 99.89（3），γ= 94.40（3）°，Z= 2，R= 0.058。对于（1），结果与最近的独立测定结果吻合良好。在（1）和（2）中，碘（III）原子形成三个具有扭曲的T形几何形状的共价键。两种化合物的I-C距离相同（2.08-2.09 nm）。两个I-O距离相同（av.（1）的结果为2.156 μ m），（2）的结果为2.136（6）和2.163（7）μ m。然而，每个碘的整体几何形状可以描述为三个强二级键和两个弱二级键的五边形平面排列。在（1）中，这两个二级I-O键都是分子内的。然而，在（2）中，其中一个配体是单齿的，另一个是不对称的双齿的，形成分子间和分子内的I-2 O接触，得到二聚体排列。讨论了（1）和（2）中次级键的形成和性质，并与其它五角-平面体系进行了比较。提出了一种可能的轨道重叠计划来解释这种几何形状。
The crystal structures of the title compounds (1) and (2) respectively have been determined at –60 °C from diffractometer data by the heavy-atom method. Crystals of (1) are orthorhombic, space group Pnn2, with unit-cell dimensions a= 15.693(3), b= 8.477(2), c= 8.762(2)Å, Z= 4, and R= 0.021 for 1 063 observed reflections. Crystals of (2) are triclinic, space group P with a= 10.462(3), b= 4.870(2), c= 15.445(5)Å, α= 101.03(3), β= 99.89(3), γ= 94.40(3)°, Z= 2, and R= 0.058 for 1 580 observed reflections. For (1) the results are in good agreement with a recent independent determination. In both (1) and (2) the iodine(III) atoms form three covalent bonds with distorted T-shaped geometry. The I–C distances in both compounds are the same (2.08–2.09 Å). The two I–O distances are the same (av. 2.156 Å) for (1) but differ significantly for (2)[2.136(6) and 2.163(7)Å]. The overall geometry of each iodine, however, can be described as a pentagonal-planar arrangement of three strong and two weak secondary bonds. In (1) both of these secondary I–O bonds are intramolecular. In (2), however, one of the ligands is unidentate, the other unsymmetrically bidentate, forming inter- and intra-molecular I ⋯ O contacts to give a dimeric arrangement. The formation and nature of the secondary bonds in (1) and (2) is discussed and compared with other pentagonal-planar systems. A possible orbital-overlap scheme is proposed to explain this geometry.