Preparation of metallaphophinoheterocycle complexes and their reactivity attained by cooperative interaction of two metal centers with a substrate

金属杂环是一种金属配体，其中一个金属-磷共价键被结合在环上。该配体有望通过磷中心上的孤对电子配位到各种金属中心，形成两个金属中心紧密相连的异双核配合物。铂或钯片段被插入到磷桥联的[1]二茂铁和氮并[1，8-b，c]磷酸盐的磷碳键上，配位到W(CO)_5片段。由此形成的金属杂环与W(CO)5片段键合，形成预期的异双核骨架。合成了一种双核金属配合物(OC)_5M(μ-1)M(CO)_5(M=W(2a)，Mo(2b)，Mo(2b)，Mo(2b)，PPh桥联的[1]二茂铁(3)在乙醚中的光解得到PPh桥联的[1.1]二茂铁(4)。通过硫化反应，成功地分离出了P(S)Ph桥联二茂铁(5)的正反异构体，并用X-射线衍射法进行了表征。加热时，ANT-3异构化为SYN-3，表明SYN-3的热力学稳定性高于ANT-3。通过SYN-3与CoCl2的反应生成了[CoCl2(syn-2)](5)，证明了syn-3作为配体的潜在用途。5的X-射线结构显示出一种新的螯合骨架，其中两个磷给体原子与两个二茂铁螯合物双键连接。

Metallaphosphaheterocycle is a kind of metalloligand in which a metal-phosphorus covalent bond is incorporated in the ring. The ligand is expected to coordinate to a variety of metal centers through lone pair electrons on the phosphorus center to form heterodinuclear complexes in which two metal centers are located in close proximity.A platinum or palladium fragment was inserted into a phosphorus-carbon bond of phosphorus-bridged [1]ferrocenophane and naphtho[1,8-b,c]phosphete coordinating to a W(CO)_5 fragment. The metallaphosphaheterocycle thus formed was bonded to the W(CO)_5 fragment to form expected heterodinuclear framework. It was found that a ligand located between two metal centers of the dinuclear complex readily dissociates from the platinum or palladium center to form a vacant coordination site.A new phosphaheterocycle in which a PhP-PPh bond bridges 1,8-positions of naphthalene, 1,2-dihydro-1,2-diphenyl-naphtho[1,8-cd]-1,2-diphosphole (1), was prepared and used as a bridging ligand for the preparation of dinuclear group 6 metal complexes (OC)_5M(μ-1)M(CO)_5 (M=W(2a),Mo(2b),Cr(2c)).Photolysis of PPh-bridged [1]ferrocenophane (3)in ether gave PPh-bridged [1.1]ferrocenophane(4). After subsequent sulfurization of the reaction mixture with elemental sulfur, both syn and anti isomers of P(S)Ph-bridged [1.1]ferrocenophane (5)were successfully isolated and characterized by X-ray analysis. Upon heating, anti-3 isomerizes to syn-3, indicating thermodynamic stability of syn-3 over anti-3. A potential utility of syn-3 as a ligand was demonstrated by the formation of [CoCl_2(syn-2)](5)through a reaction of syn-3 with CoCl_2. The X-ray structure of 5 showed a novel chelate framework in which two phosphorus donor atoms are linked doubly with two ferrocene chelates.