本論文主要為合成新型不對稱苯胺吡啶胺萘啶配基(2-phenylamino-7-( -pyridylamino)-1,8-naphthyridine,簡稱H2phapany),利用鈀金屬的催化由2,7-dichloro-1,8-naphthyridine 和aniline 及2-aminopyridine 反應而得。而脫氫之配基以螺旋的方式與金屬離子配位,可進一步形成一直線型五核鎳金屬串錯合物。根據不對稱配基中苯環的排列方向,金屬串可能有四種構型的異構物,即(4,0)、(3,1)、(2,2)-cis 和(2,2)-trans 等構型。利用不同的金屬鹽類起始物和合成方法,可成功合成出具有(3,1)和(4,0)構型的五核鎳金屬串 錯合物。 由X-ray 單晶繞射解析可知,(4,0)構型之五核鎳金屬串其一末端的鎳離子缺少了軸向配基。在鍵長比較方面,(4,0)構型金屬串之Ni(4)-Ni(5)和Ni(5)-Namido 鍵長距離較(3,1)構型分別縮短約0.09 和0.14 Å。而磁性量測結果顯示,(4,0)構型之金屬串只含有一個d8 之高自旋電子組態(S = 1);另一方面,(3,1)構型則有兩個鎳離子為d8 之高自旋電子組態,為反鐵磁性。在電化學方面,原先預期不同構型的金屬串可能有不同的氧化還原電位,然而(3,1)和(4,0)構型的五核鎳金屬串錯合物其氧化還原電位,彼此之間卻無太 大差別。 關於異構物形成的原因,先前的研究已做了不少的推論。然而在證據上稍嫌薄弱,仍需進一步努力解決這方面的問題。
The new unsymmetrical ligand, 2-phenylamino-7-( -pyridylamino)-1,8-naphthyridine(H2phapany) has been synthesized by palladium-catalyzed cross-coupling of 2,7-dichloro-1,8-naphthyridine with aniline and 2-aminopyridine. The H2phapany ligands are deprotonated and wrap around the metal ions to form a linear pentanickel complex. The complex may exist as four isomeric forms with different arrangements of the orientation of the phenyl group of the unsymmetrical ligand, i.e. the (4,0), (3,1), (2,2)-cis and (2,2)-trans forms. By using different metal salt precursors and methods of synthesis, (3,1) form and (4,0) form of pentanickel complexes could be synthesized successfully. X-ray structural studies for the (4,0) form reveal the absence of axial ligand of one terminal nickel atom. In compared the bond distances of Ni(4)-Ni(5) and Ni(5)-Namido with those of the (3,1) form, both of them in the (4,0) form are ca. 0.09 Å and 0.14 Å shorter than those in the (3,1) form. The magnetic measurements show that the (4,0) form has only one high spin nickel(II) atom (S=1), on the other hand, there are two high spin nickel(II) atoms, which are antiferromagnetically coupled in the (3,1) form. In the study of electrochemistry, we expected that the metal strings which are geometrical isomers may have different oxidative and reductive peaks. However, the CV spectra of the pentanickel complexes which are (3,1) and (4,0) forms show no significant difference. In order to study the origin of these isomers, several hypotheses have been described in this research. However, the evidences are not enough, it still need more effort to solve this problem in the future.
為了持續優化網站功能與使用者體驗,本網站將Cookies分析技術用於網站營運、分析和個人化服務之目的。
若您繼續瀏覽本網站,即表示您同意本網站使用Cookies。