對苯二腈、雙磷烷、含氮異環碳烯橋接之EFe3Cu2 (E = S, Se, Te) 錯合物: 合成、轉換、半導性以及催化

Abstract

1. S/Fe/Cu/Dppx 系統之研究 透過蒸氣揮發與機械式研磨的化學方法，具有雙磷配基dppe連結著SFe3Cu2的團簇物 [{(m3-S)Fe3(CO)9}Cu2(dppe)] 與其一維聚合物[{(m4-S)Fe3(CO)9}Cu2(dppe)(MeCN)2]n 間存在著固態可逆轉換關係。其中聚合物[{(m4-S)Fe3(CO)9}Cu2(dppe)(MeCN)2]n能隙為1.69 eV，具有半導體特性。 2. Se, Te/Fe/Cu/p-DCB 系統之研究 當固態反應物 [EFe3(CO)9Cu2(MeCN)2] (E = Se, Te) 與取代基1,4-dicyanobenzene (p-DCB) 分別以1:1 以及 1:1.5的比例混合並加入幾滴THF進行研磨，可合成兩種以EFe3(CO)9Cu2為基底THF引入且取代基p-DCB分別以單股和混合單股與雙股橋接的型式所形成之一維聚合物[SeFe3(CO)9Cu2(p-DCB)1.5•0.5THF]n (1a-THF) 與[TeFe3(CO)9Cu2(p-DCB)•THF]n (2b-THF)。X光繞射分析顯示聚合物1a-THF其上雙股p-DCB相鄰苯環間呈現平行位移排列並有著分子內pi···pi作用力且1a-THF或2b-THF其晶格溶劑THF上的氧原子可和鄰近p-DCB上的氫原子相互作用形成微弱之C─H…O氫鍵。當研磨的溶劑替換為CH2Cl2，只有得到以TeFe3(CO)9Cu2為基底，混合單股與雙股p-DCB橋接的聚合物 [TeFe3(CO)9Cu2(p-DCB)1.5]n (1b)。反之，一旦於60度加熱並抽真空，1a-THF上的晶格溶劑THF可被移除並生成聚合物 [SeFe3(CO)9Cu2(p-DCB)1.5]n (1a)。1a和1b為isomorphous且其晶體結構同呈緊密堆積。有趣地，當[EFe3(CO)9Cu2(MeCN)2] (E = Se, Te) 與取代基p-DCB以1:1.5比例混合並加入幾滴CH2Cl2/toluene (v/v = 1/1) 進行研磨，可合成出以EFe3(CO)9Cu2為基底甲苯引入且取代基p-DCB分別以混合單股與雙股橋接的型式所連接之一維聚合物[EFe3(CO)9Cu2(p-DCB)1.5•0.5toluene]n (E = Se, 1a-toluene; Te, 1b-toluene)，其中甲苯的苯環與鄰近p-DCB上傾斜苯環的氫原子形成顯著的C─H···pi作用力。此外，藉由加入溶劑THF、CH2Cl2、 CH2Cl2/toluene 或是添加額外的 p-DCB 取代基進行溶劑輔助研磨，聚合物1a、1a-THF和 1a-toluene間抑或是 1b-toluene、2b-THF和 1b間可進行可逆地固態結構轉換，伴隨著晶格溶劑的吸附與脫附、晶體位移堆積以及晶體至晶體間的膨脹與收縮現象。此外，導電度的丈量呈現出聚合物1a(1b)、1a(1b)-toluene和 2b-THF具有半導體行為 (直流電導率, 10−3−10−2 Ω−1cm−1; 能隙, 1.42−1.50 eV)，其導電度會受到pi···pi或是C─H···O作用力調控，此現象進一步使用DFT理論計算加以解釋。 3. Te/Fe/Cu/NHC 系統之研究 一新型TeFe3(CO)9併入雙銅含氮異環碳烯 (N-heterocyclic carbene) 錯合物可直接藉由一鍋化反應製備。透過引入具推電子與立障的團簇陰離子基團 [TeFe3(CO)9]2− 及含氮異環碳烯作為取代基，這些以雙銅為基底的錯合物對同耦合催化硼酸反應表現出顯著的催化活性，即少量銅承載量 (0.5 or 1.0 mol%) 以及高產率 (直達98%)。

1. S/Fe/Cu/Dppx System A reversible vapochemical and mechanochemical solid-state transformation between a dppe-linked SFe3Cu2-based cluster [{(m3-S)Fe3(CO)9}Cu2(dppe)] and its 1D polymer [{(m4-S)Fe3(CO)9}Cu2(dppe)(MeCN)2]n, was demonstrated, in which polymer [{(m4-S)Fe3(CO)9}Cu2(dppe)(MeCN)2]n exhibited semi-conducting properties with an energy gap of 1.69 eV. 2. Se, Te/Fe/Cu/p-DCB System When solid reactants [EFe3(CO)9Cu2(MeCN)2] (E = Se, Te) and 1,4-dicyanobenzene (p-DCB) were mixed in 1:1 and 1:1.5 ratios and ground with drops of THF, two EFe3(CO)9Cu2-based THF-encapsulated single/double and single/single p-DCB-linked 1D polymers [SeFe3(CO)9Cu2(p-DCB)1.5•0.5THF]n (1a-THF) and [TeFe3(CO)9Cu2(p-DCB)•THF]n (2b-THF) were obtained, respectively. X-ray analysis showed that the neighboring benzenes of the double p-DCB linkers of 1a-THF displayed a parallel-displaced geometry with an intramolecular pi···pi interaction and the oxygen atom of the lattice THF of 1a-THF or 2b-THF interacted with its adjacent hydrogen atoms of the p-DCB ligands to give weak C─H…O hydrogen bonds. When the grinding solvent changed into CH2Cl2, only TeFe3(CO)9Cu2-based single/double p-DCB-linked polymer [TeFe3(CO)9Cu2(p-DCB)1.5]n (1b) was obtained. Instead, upon heating at 60 oC under vacuum, the lattice THF of 1a-THF could be removed to give [SeFe3(CO)9Cu2(p-DCB)1.5]n (1a). 1a and 1b were isomorphous and exhibited tight crystal-packed structures. Interestingly, when [EFe3(CO)9Cu2(MeCN)2] and p-DCB were mixed in a 1:1.5 ratio and ground with CH2Cl2/toluene (v/v = 1/1), the EFe3(CO)9Cu2-based toluene-encapsulated single/double p-DCB-linked polymers [EFe3(CO)9Cu2(p-DCB)1.5•0.5toluene]n (E = Se, 1a-toluene; Te, 1b-toluene) were obtained, in which the benzene ring of the guest toluene and its adjacent hydrogen atom of the titled benzene of the p-DCB ligand showed significant C─H···pi interaction. In addition, mechanochemically reversible solid-state structural transformations among 1a, 1a-THF, and 1a-toluene, as well as 1b-toluene, 2b-THF, and 1b were achieved by grinding with THF, CH2Cl2, CH2Cl2/toluene, or additional p-DCB ligands, accompanied with the uptake and removal of the lattice solvent, the slippage of the packing layers, and crystal to crystal expansion and contraction. In addition, the measurement of conductivity showed that polymers 1a(1b), 1a(1b)-toluene, and 2b-THF exhibited semiconducting behaviors (dc conductivity, 10−3−10−2 Ω−1cm−1; energy gap, 1.42−1.50 eV) which could be tuned by weak pi···pi interaction and C─H···O hydrogen bonding, elucidated by DFT calculations. 3. Te/Fe/Cu/NHC System A new type of TeFe3(CO)9-incorporated dicopper N-heterocyclic carbene (NHC) complexes was obtained directly from one-pot reactions. By the introduction of the electron-donating and bulky cluster anion [TeFe3(CO)9]2− and NHCs as the ligands, these di-Cu(I)-based complexes exhibited pronounced catalyst activities toward the homocoupling of arylboronic acids with low Cu loadings (0.5 or 1.0 mol%) and high yields (up to 98%).