Thermodynamics of pyridine coordination in 1,4-phenylene bridged bimetallic (Pd, Pt) complexes containing two N,C,N′ motifs, 1,4-M2-[C6(CH2NR2)4-2,3,5,6]
Thermodynamics of pyridine coordination in 1,4-phenylene bridged bimetallic (Pd, Pt) complexes containing two N,C,N′ motifs, 1,4-M2-[C6(CH2NR2)4-2,3,5,6]
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DOI：
10.1021/ic061188b
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发表时间：
2006-12-25
影响因子：
4.6
通讯作者：
Craig, Stephen L.
中科院分区：
文献类型：
--
作者：
Jeon, Sung Lan;Loveless, David M.;Craig, Stephen L.
用H-1 NMR在DMSO-d(6)中测定了1,4-苯基桥接双核钯铂有机金属配合物[1,4-(MOTf)(2)-{C-6(CH2NR2)(4)-2,3,5,6}] (11, M = Pd, Pt; R = CH3, C2H5, R-2 = -(CH2)(5)-)中的吡啶配位热力学。双金属配合物11或12在DMSO中取代吡啶的配位是通过两个有效独立的金属配体结合事件进行的，并且吡啶配位的缔合常数和吡啶交换的速率常数与之前在单金属类似物上测量的结果几乎相同。吡啶配位的缔合常数与吡啶取代基的诱导Hammett常数之间存在线性自由能关系，DMSO的灵敏度（rho = -1.7 ~ -2.1）仅与金属（Pd vs Pt）和观察配体（钳形二烷基胺vs三芳基膦）有轻微的关系。然而，特定吡啶配体的缔合常数在一系列金属配合物中大约变化3个数量级。两个配位位点的有效独立性以及配位的可用热力学和动力学行为的范围指导了这些多功能构建块在金属超分子应用中的使用。
The thermodynamics of pyridine coordination in 1,4-phenylene-bridged binuclear palladium and platinum organometallic complexes [1,4-(MOTf)(2)-{C-6(CH2NR2)(4)-2,3,5,6}] (11, M = Pd, Pt; R = CH3, C2H5, R-2 = -(CH2)(5)-) are measured by H-1 NMR in DMSO-d(6). The coordination of substituted pyridines by bimetallic complexes 11 or 12 in DMSO is found to proceed via two effectively independent metalligand binding events, and the association constants for pyridine coordination and rate constants for pyridine exchange are nearly identical to those measured previously on monometallic analogs. A linear free energy relationship between the association constant for pyridine coordination and the inductive Hammett constant of the pyridine substituent is observed, and the sensitivity (rho = -1.7 to -2.1) in DMSO depends only slightly on metal ( Pd vs Pt) and spectator ligand ( pincer dialkylamine vs triarylphosphine). The association constant for a particular pyridine ligand, however, varies by roughly 3 orders of magnitude across the series of metal complexes. The effective independence of the two coordination sites and the range of available thermodynamic and kinetic behaviors of the coordination guide the use of these versatile building blocks in metallosupramolecular applications.