DYNAMIC NUCLEAR-MAGNETIC-RESONANCE STUDY OF THE EFFECTS OF CIS-CHELATE LIGANDS ON 1.2-METALLOTROPIC SHIFTS IN TRIMETHYLPLATINUM(IV) COMPLEXES OF PYRIDAZINE
DYNAMIC NUCLEAR-MAGNETIC-RESONANCE STUDY OF THE EFFECTS OF CIS-CHELATE LIGANDS ON 1.2-METALLOTROPIC SHIFTS IN TRIMETHYLPLATINUM(IV) COMPLEXES OF PYRIDAZINE
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DOI：
10.1039/dt9950003165
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发表时间：
1995-10-07
期刊：
影响因子：
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通讯作者：
MALIK, KMA
中科院分区：
文献类型：
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作者：
ABEL, EW;HEARD, PJ;MALIK, KMA
配合物 fac-[PtMe(3)(L-L)(pydz)][BF4]（L-L = 中性二齿螯合配体；pydz = 哒嗪）很容易由 fac-[PtlMe(3)(L-L)] 在过量哒嗪存在下通过银 (I) 盐的作用制备。哒嗪作为单齿配体，在两个等价、连续的氮供体原子之间发生容易的 1,2- 金属转变。这些配合物的溶液态立体动力学已通过二维交换光谱和推导的准确激活参数得到阐明。能量势垒[Delta Gt(双匕首)(298 K)]在58-78 kJ mol(-1)范围内。讨论并合理化了螯合配体对通量位移能量学的影响。测定 fac-[PtMe(3)(bipy)(pydz)][BF4] (bipy = 2,2'-联吡啶) 的晶体结构，以确认配合物的面八面体配位几何形状。
The complexes fac-[PtMe(3)(L-L)(pydz)][BF4] (L-L = neutral bidentate chelate ligand; pydz = pyridazine) were readily prepared from fac-[PtlMe(3)(L-L)], by the action of silver(I) salts in the presence of an excess of pyridazine. Pyridazine is acting as a monodentate ligand, which undergoes a facile 1,2-metallotropic shift between the two equivalent, contiguous nitrogen donor atoms. The solution-state stereodynamics of these complexes have been elucidated by two-dimensional exchange spectroscopy and accurate activation parameters deduced. Energy barriers [Delta Gt(double dagger)(298 K)] are in the range 58-78 kJ mol(-1). The effects of the chelate ligand on the energetics of the fluxional shift are discussed and rationalised. The crystal structure of fac-[PtMe(3)(bipy)(pydz)][BF4] (bipy = 2,2'-bipyridyl) was determined to confirm the fac-octahedral co-ordination geometry of the complexes.