Robertson Daniel, Cannon John F, Gerasimchuk Nikolay
Department of Chemistry, Southwest Missouri State University, Temple Hall 456, Springfield, Missouri 65804, USA.
Inorg Chem. 2005 Nov 14;44(23):8326-42. doi: 10.1021/ic050465w.
The design of new types of metal-organic networks and the search for unusual crystal architecture represents an important task for modern inorganic and materials chemistry research. A group of new monosubstituted phenylcyanoximes, containing F, Cl, and Br atoms at the 2, 3, or 4 positions, were synthesized using the high yield nitrosation reaction with CH3-ONO and were spectroscopically (1H NMR, 13C NMR, UV-visible, IR, mass spectrometry) and structurally characterized. Results of X-ray analysis revealed nonplanar trans-anti geometry for 2-chlorophenyl(oximino)acetonitrile, H(2Cl-PhCO); a nonplanar anti configuration for 4-chlorophenyl(oximino)acetonitrile, H(4Cl-PhCO); and planar cis-syn geometry for 3-fluorophenyl(oximino)acetonitrile, H(3F-PhCO). All arylcyanoximes undergo deprotonation in solutions with the formation of colored anions exhibiting pronounced negative solvatochromism in a series of polar protic and aprotic solvents. Nine thallium(I) cyanoximates were obtained using the reaction between hot (approximately 95 degrees C) aqueous solutions of Tl2CO3 and solid powdery monohalogenated arylcyanoximes HL. Crystal structures of two Tl(I) cyanoximates [Tl(2Cl-PhCO) and Tl(4Br-PhCO)] contained centrosymmetric dimeric units (TlL)2 that are connected to a coordination polymer by means of an oxygen atom of the oxime group of the neighboring molecule. Cyanoxime anions act as bridging ligands in both structures where the polymeric motif consists of double-stranded Tl-O chains interconnected with the formation of zigzagging Tl2O2 planar rhombes. Thallium atoms form infinite linear arrays with close intermetallic separations. The nearest Tl(I)...Tl(I) distances are 3.838 and 4.058 angstroms in the Tl(2Cl-PhCO) and Tl(4Br-PhCO) structures, respectively, close to that in metallic thallium (3.456 angstroms). Monosubstituted phenyl groups are well aligned in pi-stacking columns that are perpendicular to the array of Tl(I) atoms and stabilize formed structures. Coordination polyhedrons of thallium(I) in these complexes represent distorted trigonal pyramids with stereoactive lone pair.
新型金属有机网络的设计以及对独特晶体结构的探索是现代无机化学和材料化学研究的一项重要任务。通过与CH3-ONO进行高产率亚硝化反应，合成了一组在2、3或4位含有F、Cl和Br原子的新型单取代苯基氰肟，并通过光谱（1H NMR、13C NMR、紫外可见光谱、红外光谱、质谱）和结构表征对其进行了研究。X射线分析结果表明，2-氯苯基（肟基）乙腈H(2Cl-PhCO)具有非平面反式-反式构型；4-氯苯基（肟基）乙腈H(4Cl-PhCO)具有非平面反式构型；3-氟苯基（肟基）乙腈H(3F-PhCO)具有平面顺式-顺式构型。所有芳基氰肟在溶液中都会发生去质子化，形成带色阴离子，这些阴离子在一系列极性质子溶剂和非质子溶剂中表现出明显的负溶剂化显色作用。通过Tl2CO3的热（约95℃）水溶液与固体粉末状单卤代芳基氰肟HL之间的反应，得到了九种铊（I）氰肟酸盐。两种铊（I）氰肟酸盐[Tl(2Cl-PhCO)和Tl(4Br-PhCO)]的晶体结构包含中心对称的二聚单元（TlL）2，这些单元通过相邻分子肟基的氧原子连接到配位聚合物上。氰肟阴离子在两种结构中均作为桥连配体，其中聚合物基序由双链Tl-O链组成，这些链相互连接形成锯齿状的Tl2O2平面菱形。铊原子形成具有紧密金属间距离的无限线性阵列。在Tl(2Cl-PhCO)和Tl(4Br-PhCO)结构中，最近的Tl（I）...Tl（I）距离分别为3.838和4.058埃，接近金属铊中的距离（3.456埃）。单取代苯基在垂直于Tl（I）原子阵列的π堆积柱中排列良好，并稳定了形成的结构。这些配合物中铊（I）的配位多面体代表具有立体活性孤对的扭曲三角锥。
