[M(cyclam)(CCR)2 ] OTf类型的炔基配合物(其中cyclam = 1,4,8,11-四氮杂十四烷; M = Rh(III)或Cr(III); R =苯基,4-甲基苯基(4-三氟甲基苯基,4-氟苯基,1-萘基,9-菲基和环己基)的制备方法为一锅法合成,其中将2当量的RCCH和4当量的BuLi加入到在THF中合适的[M(cyclam)(OTf)2 ] OTf络合物。使用溶解度差异分离炔基配合物的顺式和反式异构体,并使用红外光谱法对CH 2摇摆和NH弯曲区域进行立体化学表征。所有的反式-[M(cyclam)(CCR)2]光学传递函数显示出复合物2071和2109厘米之间的强拉曼频带-1,归因于ν小号(C≡C)。Cr(III)配合物的拉伸频率比类似的Rh(III)配合物低21–28 cm –1,这一结果可以用炔基配体作为π供体来解释。Cr(III)和Rh(III)配合物的紫外可见
已经制备了反式-[Co(cyclam)(CCR)2 ] OTf类型的炔基配合物,并通过UV-Vis光谱,1 H NMR,振动光谱(红外和拉曼光谱)和循环伏安法进行了表征。在适当的情况下,将数据与相应的Cr(III)和Rh(III)配合物进行比较。尽管已表明芳基炔基配体充当相应Cr(III)配合物的π供体,但振动光谱表明,芳基炔基配体与Co(III)之间的π相互作用非常弱,并且吸电子性更高的三氟丙炔基配体可能表现为对Co(III)的弱π受体。反式-[Co(cyclam)(CCCF 3)2的X射线晶体结构还报道了] OTf和反式-[Cr(cyclam)(CCCF 3)2 ] OTf,并且对MC和CC键长的分析与对三氟丙炔基配体的这种理解是一致的。反式-[Co(cyclam)(CCR)2 ] OTf配合物的循环伏安法表明,当R = C 6 H 5或p -C 6 H 4 CH 3时,Co III /
Emissive Chromium(III) Complexes with Substituted Arylethynyl Ligands
作者:David L. Grisenti、W. Walsh Thomas、Christopher R. Turlington、Matthew D. Newsom、Christopher J. Priedemann、Donald G. VanDerveer、Paul S. Wagenknecht
DOI:10.1021/ic801376p
日期:2008.12.15
Arylethynylchromium(III) complexes of the form trans-[Cr(cyclam)(CCC(6)H(4)R)(2)]OTf (where cyclam = 1,4,8,11-tetraazacyclotetradecane, R = H, CH(3), or CF(3) in the para position, and OTf = trifluoromethanesulfonate) have been prepared and characterized by IR spectroscopy and X-ray diffraction. The complexes are emissive with excited-state lifetimes in a deoxygenated fluid solution between 200 and
The crystal structures and magnetic properties of new molecule-based magnets, [CrCyclam(C C-3-thiophene)(2)][Ni(mdt)(2)] (1) and [CrCyclam(C C-Ph)(2)][Ni(mdt)(2)](H2O) (2) (Cyclam = 1,4,8,11-tetraazacyclotetradecane, mdt = 1,3-dithiole-4,5-dithiolate), are reported. The crystal structures of both compounds are characterized by ferrimagnetic chains of alternately stacked [CrCyclam(C C-R)](+) cations and [Ni(mdt)(2)](-) anions with intrachain exchange interactions of 2J = -6.1 K in 1 and -5.7 K in 2 (H = -2J Sigma S-i(i)center dot Si+1). The material 1 exhibits ferrimagnetic transition at 2.3 K owing to weak interchain antiferromagnetic interactions between cations and anions. In the case of 2, cations in adjacent ferrimagnetic chains are bridged by a water molecule, resulting in an interchain antiferromagnetic coupling. Despite a centrosymmetry of a whole crystal of 2, one bridging water molecule occupies only one of the two centrosymmetric sites and breaks a local centrosymmetry between adjacent cations. The interchain antiferromagnetic interaction and Dzyaloshinsky-Moriya interaction originated from the local symmetry breakdown of 2 bring a weak-ferromagnetic transition at 3.7 K with a coercive force of less than 0.8 mT, followed by the second magnetic phase transition at 2.9 K. Below this temperature, the coercive force rapidly increases from 1 to 11.8 mT as the temperature decreases from 2.9 to 1.8 K, while the remanent magnetization monotonically increases from 0.008 mu(B) at 3.6 K to 0.12 mu(B) at 1.8 K.