AN NMR INVESTIGATION OF 1,2-METALLOTROPIC SHIFTS IN TRANSITION-METAL COMPLEXES OF BENZO[C]CINNOLINE AND PYRIDAZINES

被引:16
|
作者
ABEL, EW [1 ]
BLACKWALL, ES [1 ]
ORRELL, KG [1 ]
SIK, V [1 ]
机构
[1] UNIV EXETER,DEPT CHEM,EXETER EX4 4QD,DEVON,ENGLAND
关键词
TUNGSTEN; RHODIUM; PYRIDAZINE; NUCLEAR MAGNETIC RESONANCE; METALLOTROPIC SHIFT;
D O I
10.1016/0022-328X(94)87270-8
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
Complexes of types [W(CO)(5)L], [cis-Rh(CO)(2)C1L] (L = benzo[c]cinnoline) and [W(CO)(5)L'] (L' = pyridazine, 3-methylpyridazine, and 4-methylpyridazine) have been synthesized and shown to exhibit, in organic solvents, intramolecular metal-nitrogen 1,2-fluxional shifts, which have been quantitatively studied by ID bandshape analysis and 2D-EXSY NMR experiments. Energy barriers for the metallotropic shifts in the pyridazine complexes are ca. 20 kJ mol(-1) higher than in the benzo[c]cinnoline complexes. These differences are discussed in terms of the ground state and likely transition state species for this fluxional process.
引用
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页码:163 / 170
页数:8
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