Electrochemistry of five- and six-coordinate .sigma.-bonded cobalt porphyrins. Reactions of (TPP)Co(C2H5)(py) and (TPP)Co(R) where TPP is the dianion of tetraphenylporphyrin and R = CH3, C2H5, or CH2Cl
Electrochemistry of five- and six-coordinate .sigma.-bonded cobalt porphyrins. Reactions of (TPP)Co(C2H5)(py) and (TPP)Co(R) where TPP is the dianion of tetraphenylporphyrin and R = CH3, C2H5, or CH2Cl
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五配位和六配位σ键合钴卟啉的电化学。
DOI：
10.1021/ic00024a008
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
A. Endo
中科院分区：
文献类型：
--
作者：
K. Kadish;B. Han;A. Endo
在吡啶、四氢呋喃和二氯甲烷中，以0.1 M高氯酸四丁基铵或0.1 M六氟磷酸四丁基铵为支撑电解质，研究了五和六坐标钴键卟啉的电化学反应。所研究的化合物表示为（TPP） Co (C2H5)（py）和（TPP） Co (R)，其中TPP是四苯基卟啉的离子，R= CH3， C2H5或CH2C1。每个络合物经历两次还原和两次氧化，所有这些都发生在卟啉环系统中。（TPP） Co （CH3）的电化学数据与（TPP） M （CH3）的数据进行了比较，其中M= Rh, Al, Ga， In或T1，并清楚地表明Co （III）配合物在非水介质中没有金属中心还原。计算了（TPP） Co （C2H5）在CH2C12中转化为（TPP） Co (C2H $)（py）的生成常数K= 8.9，并研究了（TPP） Co (C2H5)（py）在吡啶中的电化学反应。这种六配位物质的氧化涉及在相同电位下的整体双电子转移，并导致[(TPP) Co (py) 2]+和[C5H5N (C2H5)]+，后者通过与在相同溶液条件下研究的C5H5N (C2H5) Br样品进行电化学鉴定。
The electrochemistry of five-and six-coordinate cobalt (lll)-bonded porphyrins is reported in pyridine, tetrahydrofuran, and methylene chloride containing 0.1 M tetrabutylammonium perchlorate or 0.1 M tetrabutylammonium hexafluorophosphate as supporting electrolyte. The investigated compounds are represented as (TPP) Co (C2H5)(py) and (TPP) Co (R) where TPP is the dianion of tetraphenylporphyrin and R= CH3, C2H5, or CH2C1. Each complex undergoes up to two reductions and two oxidations, all of which occur at the porphyrin ring system. The electrochemical data for (TPP) Co (CH3) are compared to data for (TPP) M (CH3) where M= Rh, Al, Ga, In, or T1 and clearly indicate the absence of a metal-centered reduction for the Co (III) complex in nonaqueous media. The formation constant for conversion of (TPP) Co (C2H5) to (TPP) Co (C2H $)(py) was calculated as K= 8.9 in CH2C12, and the electrochemistry of (TPP) Co (C2H5)(py) was also investigated in pyridine. The oxidation of this six-coordinate species involves an overall two-electron transfer at the same potential andleads to [(TPP) Co (py) 2]+ and [C5H5N (C2H5)]+, the latter of which was electrochemically identified by comparison to a sample of C5H5N (C2H5) Br which was investigated under the same solution conditions.