The Influence of Peripheral Substituent Modification on PV, MnIII, and MnV(O) Corrolazines: X-ray Crystallography, Electrochemical and Spectroscopic Properties, and HAT and OAT Reactivities
The Influence of Peripheral Substituent Modification on PV, MnIII, and MnV(O) Corrolazines: X-ray Crystallography, Electrochemical and Spectroscopic Properties, and HAT and OAT Reactivities
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DOI：
10.1021/acs.inorgchem.6b01219
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发表时间：
2016-09-05
影响因子：
4.6
通讯作者：
Goldberg, David P.
中科院分区：
文献类型：
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作者：
Joslin, Evan E.;Zaragoza, Jan Paulo T.;Goldberg, David P.
研究了远端外周取代对磷、锰腐蚀嗪（Cz）配合物理化性质和反应活性的影响。p-MeO取代了Cz环上8个苯取代基上的p-t-Bu基团，导致了每个配合物的紫外-可见跃迁和氧化还原电位的变化。p-MeO取代对Mn-V(O)配合物的氧原子转移（OAT）和氢原子转移（HAT）反应活性也有影响。Mn-V(O)(MeOP(8)Cz) (MeOP（8)Cz = octakis-（对甲氧基苯基）腐蚀（3-））与三芳基膦（PAr3）底物的OAT反应性导致二级速率常数从10.2(5)到3.1(2)× 10(4) M-1 s（-1）。这些OAT速率比Mn-V(O)(TBP(8)Cz) (TBP（8)Cz = octakis（对叔丁基苯基）腐蚀（3-））慢。一项涉及PAr3基质的Hammett研究显示，Mn- v (O)（MeOP(8)Cz）的Hammett p值比Mn- v (O)（TBP(8)Cz）的p值更负，这与Mn中心亲电性较低相一致。测定了Mn-V(O)（MeOP(8)Cz）与C-H底物的HAT反应活性，发现其二级反应速率常数为6.8(5)× 10(-5) ~ 1.70(2) × 10(-1) m - 1s（-1）。速率常数随基体碳-氢键强度的变化而变化。与Mn-V(O)（TBP(8)Cz）相比，Mn-V(O)（MeOP(8)Cz）对C-H底物的HAT速率略快，这表明假定的[Mn-IV(O)]（-）中间体的碱性可能补偿了HAT驱动力中更负的氧化还原电位。此外，还完整、大规模地合成了对苯基取代的卟啉类化合物RP8PzH2 （R =对叔丁基苯基（TB）、对甲氧基苯基（MeO）和对异丙基苯基）和腐蚀嗪类化合物RP(8)CzH(3) (TBP(8)CzH(3)和MeOP（8)CzH(3)）。介绍了单质子化无金属腐蚀嗪[(TBP(8)CzH(3))(H)](+)[BArF]（-）、P-V(OMe)(2)(-) （MeOP(8)Cz）和Mn-III(MeOP(8)Cz)（MeOH）的晶体结构。这项工作提供了对电子取代基效应对腐蚀外围的影响的第一个见解。
The influence of remote peripheral substitution on the physicochemical properties and reactivity of phosphorus and manganese corrolazine (Cz) complexes was examined. The substitution of p-MeO for p-t-Bu groups on the eight phenyl substituents of the beta-carbon atoms of the Cz ring led to changes in UV-vis transitions and redox potentials for each of the complexes. The oxygen atom transfer (OAT) and hydrogen atom transfer (HAT) reactivity of the Mn-V(O) complexes was also influenced by p-MeO substitution. The OAT reactivity of Mn-V(O)(MeOP(8)Cz) (MeOP(8)Cz = octakis-(p-methoxyphenyl)corrolazinato(3-)) with triarylphosphine (PAr3) substrates led to second-order rate constants from 10.2(5) to 3.1(2) x 10(4) M-1 s(-1). These rates of OAT are slower than those seen for Mn-V(O)(TBP(8)Cz) (TBP(8)Cz = octakis(p-tertbutylphenyl)corrolazinato(3-)). A Hammett study involving para-substituted PAr3 substrates reveals a Hammett p-value for Mn-V(O)(MeOP(8)Cz) that is more negative than that observed for Mn-V(O)(TBP(8)Cz), consistent with a less electrophilic Mn center. The HAT reactivity of Mn-V(O)(MeOP(8)Cz) with C-H substrates was examined and revealed second-order rate constants from 6.8(5) x 10(-5) to 1.70(2) X 10(-1) M-1 s(-1). The rate constants varied with the C-H bond strength of the substrate. Slightly faster HAT rates with C-H substrates were observed with Mn-V(O)(MeOP(8)Cz) compared to Mn-V(O)(TBP(8)Cz), indicating that the basicity of the putative [Mn-IV(O)](-) intermediate likely compensates for the more negative redox potential in the driving force for HAT. In addition, the complete, large-scale synthesis of the para-phenyl-substituted porphyrazines RP8PzH2 (R = p-tertbutylphenyl (TB), p-methoxyphenyl (MeO), and p-isopropylphenyl) and corrolazines RP(8)CzH(3) (TBP(8)CzH(3) and MeOP(8)CzH(3)) is presented. The crystal structures of the monoprotonated, metal-free corrolazine [(TBP(8)CzH(3))(H)](+)[BArF](-), P-V(OMe)(2)(-) (MeOP(8)Cz), and Mn-III(MeOP(8)Cz)(MeOH) are presented. This work provides the first insights into the influence of electronic substituent effects on the corrolazine periphery.