Gupta Vijay, Khullar Sadhika, Kumar Sandeep, Mandal Sanjay K
Department of Chemical Sciences, Indian Institute of Science Education and Research, Mohali, Sector 81, Manauli PO, S.A.S. Nagar, Mohali, Punjab 140306, India.
Dalton Trans. 2015 Oct 14;44(38):16778-84. doi: 10.1039/c5dt02354h. Epub 2015 Sep 4.
With numerous examples of heavier congeners as well as neighbors, only four paddlewheel compounds, including one coordination architecture, of manganese with the [Mn(μ-O2CR)4L2] core were reported in the literature. We report here a robust pillared-layer framework with an α-polonium topology comprising such a core as a subunit, {[Mn2(O2CC6H4Si(CH3)2C6H4CO2)2(4,4'-bpy)]}n (1), where 4,4'-bpy = 4,4'-bipyridine, with an MnMn distance of 3.005(2) Å, which does not vary with temperature. For the first time, the variable temperature magnetic data (2-300 K) and crystal structures at two different temperatures (100 K and 296 K) are combined for the same example to support the fact that there is no metal-metal bond in such compounds like 1. Based on the magnetic measurements, an antiferromagnetic interaction (2J = -12.4 cm(-1) with g = 2.014 (H = -2JS1S2)) between two S1 = S2 = 5/2 spin centers exists in 1.
由于存在众多较重同系物以及相邻物的实例，文献中仅报道了四种具有[Mn(μ - O₂CR)₄L₂]核心的锰的桨轮化合物，其中包括一种配位结构。我们在此报道一种具有α - 钋拓扑结构的坚固柱状层框架，其包含这样一个核心作为亚基，即{[Mn₂(O₂CC₆H₄Si(CH₃)₂C₆H₄CO₂)₂(4,4'-bpy)]}ₙ (1)，其中4,4'-bpy = 4,4'-联吡啶，Mn - Mn距离为3.005(2) Å，该距离不随温度变化。首次针对同一实例结合了变温磁性数据（2 - 300 K）和两个不同温度（100 K和296 K）下的晶体结构，以支持像1这样的化合物中不存在金属 - 金属键这一事实。基于磁性测量，在1中两个S₁ = S₂ = 5/2自旋中心之间存在反铁磁相互作用（2J = -12.4 cm⁻¹，g = 2.014 (H = -2JS₁S₂)）。
