NEW SERIES OF MULTIFUNCTIONALIZED NICKEL(II) - CYCLAM (CYCLAM = 1,4,8,11-TETRAAZACYCLOTETRADECANE) COMPLEXES - APPLICATION TO THE PHOTOREDUCTION OF CARBON-DIOXIDE
NEW SERIES OF MULTIFUNCTIONALIZED NICKEL(II) - CYCLAM (CYCLAM = 1,4,8,11-TETRAAZACYCLOTETRADECANE) COMPLEXES - APPLICATION TO THE PHOTOREDUCTION OF CARBON-DIOXIDE
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DOI：
10.1021/ic00082a025
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发表时间：
1994-02-16
影响因子：
4.6
通讯作者：
OKAZAKI, Y
中科院分区：
文献类型：
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作者：
KIMURA, E;WADA, S;OKAZAKI, Y
合成了两种Ni（II）-cyclam（cyclam = 1，4，8，11-四氮杂环十四烷）配合物，并将其用于CO2光还原催化。第一类型（4a，[Ni（II）（6-（（N-甲基吡啶-4-基）甲基）-1，4，8，11-四氮杂环十四烷）]; 4 b，[Ni（II）（6-（（N-（对甲基苄基）吡啶-4-基）甲基）-1，4，8，11-四氮杂环十四烷）];4c，[Ni（II）-（6-（（N-苄基吡啶-4-基）甲基）-1，4，8，11-四氮杂环十四烷）]; 4d，[Ni（II）（6-（（N-（对硝基苄基）吡啶-4-基）甲基）-1，4，8，11-四氮杂环十四烷）]）带有季吡啶鎓侧基部分作为潜在的电子受体。发现每个阳离子吡啶部分的还原电位比相应的Ni（II）中心更正。在pH5.1，0.1M的抗坏血酸缓冲溶液中，考察了它们对Ru（bpy）32+光催化还原CO2的催化性能，4a-d的CO释放量分别是未衍生的Ni（II）-cyclam（1）的3、5.3、5.8和5.1倍。每个吡啶阳离子的还原电位和CO的量之间存在密切的相关性。作为第二类镍配合物，合成了一个新的双功能超分子Ru（bpy）2（bpy-py-cyclam-Ni（II））（5）（bpy-py-cyclam =（6-（（N-（（4 ′-甲基-2，2 ′-联吡啶-4-基）甲基）吡啶-4-基）甲基）-1，4，8，11-泰特氮杂环十四烷），并研究了其光谱、氧化还原和CO2催化性能. 5的激发态的寿命足够长，以允许在抗坏血酸盐的存在下还原淬灭。虽然该过程诱导了5的还原光裂解，但催化研究表明，与Ru（bpy）3（2+）、吡啶盐和Ni（II）-cyclam（1）的多分子系统复合物相比，产生的CO量是其两倍。
Two types of Ni(II)-cyclam complex (cyclam = 1,4,8,11-tetraazacyclotetradecane) have been synthesized for CO2 photoreduction catalysis. The first type (4a, [Ni(II)(6-((N-methylpyridin-4-yl)methyl)-1,4,8,11-tetraazacyclotetradecane)]; 4b, [Ni(II)(6-((N-(p-methoxylbenzyl)pyridin-4-yl)methyl)-1,4,8,11-tetraazacyclotetr adecane)];4c, [Ni(II)-(6-((N-benzylpyridin-4-yl)methyl)-1,4,8,11-tetraazacyclotetradecane)]; 4d, [Ni(II)(6-((N-(p-nitrobenzyl)pyridin-4-yl)methyl)-1,4,8,11-tetraazacyclotetrade cane)]) bear a quaternary pyridinium pendant moiety as a potential electron acceptor. The reduction potential of each cationic pyridinium moiety was found to be more positive than the respective Ni(II) center. Their catalytic behavior toward the photoreduction of CO2 with Ru(bpy)32+ as a photosensitizer was examined in ascorbate buffer (pH 5.1, 0.1 M) and the evolved amounts of CO by 4a-d were respectively, 3, 5.3,5.8, and 5.1 times greater than that from underivatized Ni(II)-cyclam (1). A close correlation was found between the reduction potential of each pyridinium cation and the quantity of CO evolved. As a second type of Ni(II) complex, a new bifunctional supermolecule Ru(bpy)2(bpy-py-cyclam-Ni(II)) (5) (bpy-py-cyclam = (6-((N-((4'-methyl-2,2'-bipyridin-4-yl)methyl)pyridin-4-yl)methyl)-1,4,8,11-tet raazacyclotetradecane) has been synthesized, and its spectroscopic, redox, and CO2 catalytic properties have been investigated. The lifetime of the excited state of 5 is long enough to permit reductive quenching in the presence of ascorbate. Although this process induced reductive photocleavage of 5, catalytic studies show that twice the amount of CO is produced compared with a multimolecular system composite of Ru(bpy)3(2+), pyridinium salt, and Ni(II)-cyclam (1).