Organolanthanide hydride chemistry. 3. Reactivity of low-valent samarium with unsaturated hydrocarbons leading to a structurally characterized samarium hydride complex

Abstract

formed, the first one, a hemoprotein Fe(II)-CH3N=NH complex being further oxidized by 1 equiv of Fe(CN)6K3 (or by 02) to give another complex, B, of unknown structure. When R = C6H5, the Fe(II)-C6H5N=NH complex has never been observed, the only entity formed being a complex spectrally similar to B.27 This paper describes the first isolation of a porphyriniron(II)-alkyldiazene complex22 and points to the great instability of Fe(II)-C6H5N=NH complexes, thus strongly supporting the existence of Mb-(or Hb-) Fe(II)-CH3N=NH complexes10 and explaining the failure to observe Mb-Fe(II)-C6H5N=NH complexes.93•10,23The diazene ligands are isoelectronic with their oxygen-containing analogues, nitrosoalkanes15 and 02, and it is noteworthy that, as their diazene analogues, nitrosoarene-iron porphyrin complexes are considerably less stable than nitrosoalkane-iron complexes.150This paper also reports for the first time the formation of -Fe-(III)-R complexes upon reaction of RNHNH2 or RN=NH with iron porphyrins, indicating a possible HbFem-R (R = CH3 or C6H5) structure for complexes B.27 However, one cannot exclude presently the previously proposed9 HbFem-N=NR structure for these complexes. In that respect, it is noteworthy that hydrazines RNHNH2 react with Co and Fe chelates to give Co(III)-R and Fe(III)-R complexes,24 whereas C6H5NHNH2 reacts with molybdenum porphyrins to give Finally, very recent preliminary results are in favor of the formation of similar iron complexes during the cytochrome P-450 dependent oxidation of CH3NHNH226 and C6H5NHNH2.3•26 (21) (a) Reed, C.

Stabilization of a Discrete Lanthanide(II) Hydrido Complex by a Bulky Hydrotris(pyrazolyl)borate Ligand

“…Therefore the structure of 1 was determined by single-crystal X-ray diffraction (Figure 1), which revealed the dimeric nature of the com- [4] The Yb´´´Yb' distances of 3.659(1) and 3.641(1) in the two independent dimers of 1 are shorter than the metal ± metal distances of the related Ln III complexes [11] [{(CH 3 C 5 H 4 ) 2 Ln(thf)(m-H)} 2 ] (Ln Y: 3.664(1) , Er: 3.616(5) ), [8] (2) ), [12] and [{(C 5 Me 5 ) 2 Sm(m-H)} 2 ] (3.905(3) ). [13] The large distance in the last-named complex probably reflects steric constraints imposed by the bulky C 5 Me 5 ligands.…”

“…The NMR spectroscopic data showed the product to be the ene ± diolate 4. Calculation of the coupling constants from the NMR data of the 13 [16a] hence, 4 was assigned as the cis isomer. The related [{(C 5 Me 5 ) 2 SmH} 2 ] was also reported to react with CO to form the cis ene ± diolate.…”

Bis(phosphinimino)methanide Rare Earth Amides: Synthesis, Structure, and Catalysis of Hydroamination/Cyclization, Hydrosilylation, and Sequential Hydroamination/Hydrosilylation

“…In lanthanide chemistry, alkyl, amido, and hydrido cyclopentadienyl complexes, especially metallocenes such as [Ln-A C H T U N G T R E N N U N G (C 5 Me 5 ) 2 R] (R = CHA C H T U N G T R E N N U N G (SiMe 3 ) 2 , NA C H T U N G T R E N N U N G (SiMe 3 ) 2 , H), have proven to be highly efficient catalysts [1] for a variety of olefin transformations including hydrogenation, [2][3][4][5] polymerization, [6][7][8] hydroamination, [4,9] hydrosilylation, [10,11] hydroboration, [12] and hydrophosphination. [13] In addition to the well established cyclopentadienyl complexes, a number of non-cyclopentadienyl lanthanide complexes based on amido and alkoxide ligands are today also known to be active in hydroamination/cyclization catalysis.…”

Sixty Years of the Chemistry of Rare-earth Organometallic Complexes

“…[(C 5 Me 5 ) 2 LuH] 2 的制备是通过甲基配合物氢 解反应来实现, 后来发现氢解二(三甲基硅)甲基配合物 也能合成氢化物[式 (9)]. 生成的稀土金属氢化物是不含 溶剂配位的二聚体, 其中钐氢化物的结构经单晶 X-射 线衍射分析确认 [114] . 它们在非极性溶剂中有中等程度 的溶解度, 并被用于一些计量和催化反应中, 如烯烃齐 聚, 烯烃氢化以及 C-H 键活化等.…”