同碳雙碳烯 (carbodicarbene, CDC) 以及彎曲型重烯為透過中心零價碳與兩個含氮雜環碳烯 (N-heterocyclic carbene, NHC) 進行配位，並且中心碳具有兩對孤對電子的結構，因此具有很強的供電子能力。而在雙金屬錯合物的研究上，與之結構類似的同碳雙磷烷 (carbodiphosphorane, CDP) 早已被發表出相同金屬或相異金屬的雙金屬錯合物，但在同碳雙碳烯部分卻還沒被成功純化出來，所以在這方面的研究還需要許多開發，因此在合成上我們嘗試透過鍵結了硼原子作為陰離子的鉗型重烯來合成其雙金屬錯合物。透過晶體結構可以得知鉗型重烯 (2) 具有類似BODIPY的骨架，並且為兩性離子化合物，若與Pd(COD)Cl2進行反應可以得到 {Pd}-Cl, {Pd} = [allene]Pd (3)，但透過DFT進行理論計算卻發現中心碳與鈀金屬是以共價鍵的方式來鍵結，故稱此化合物為丙烯基陽離子鈀金屬錯合物。接著透過加入AgX (X=OAc, OTf) 能夠將化合物3的氯原子替換掉，得到 {Pd}-OAc (4) 及 [{Pd}-NCCH3]+[OTf]- (5) 兩種不同的配位基與鈀金屬鍵結的結構。若將化合物3分別與AgOTf及(Ph3P)AuNTf2進行反應，誘導出中心碳上的第二對孤對電子，可獲得兩金屬皆分別與中心碳進行鍵結的雙金屬錯合物Pd(II)-Ag(I) (6) 及Pd(II)-Au(I) (7)，並藉由X-ray單晶繞射解析鑑定其結構。;Carbodicarbenes (CDCs) or bent allenes (CL2) are carbones that feature a dicoordinated central carbon (C0) bearing two lone pairs of electrons with N-heterocyclic carbenes (NHCs) as ligand (L). Due to the two lone pairs on carbons, CDCs have been regarded as strong -donating ligand than NHC counterparts. To date, the CDC coordinated to bimetallic transition metal complexes have not been isolated, though homo- and heterobimetallic complexes has been reported for related carbodiphosphoranes (CDPs). In an attempt to synthesize heterometallic CDC complexes, efforts would be made on the modification of the pincer-type allene moiety by fusing with anionic borate moiety. The solid-state structure of 2 has revealed a BODIPY-like core and zwitterion. The treatment of 2 with Pd(COD)Cl2 resulted in formation of {Pd}-Cl, {Pd} = [allene]Pd (3). However, the DFT result suggested that the bonding between the center carbon and palladium is a covalent bond (namely allylic cation palladium complex). Chloride abstraction of 3 by AgX (X = OAc, OTf) afforded {Pd}-OAc (4) and [{Pd}-NCCH3]+[OTf]- (5), respectively. Reaction of 3 with AgOTf and [(Ph3P)Au][NTf2] in THF afforded gem-bimetallic species, which are tentatively formulated as heterometallic Pd(II)-Ag(I) (6) and Pd(II)-Au(I) (7) complexes, in which the d8 Pd(II) and d10 M(I) centres are bridged by a carbon. Based on the experimental result suggesting the 2nd lone pair of carbon can be activated by addition of Lewis acid. The crystal structure of Pd(II)-Ag(I) (6) and Pd(II)-Au(I) (7) have been characterized.
