Development of New Chemical Nitrogen Fixation.

最近，我们发现了钨二氮配合物与酸性钌η^2-二氢配合物在温和条件下生成氨的新反应，尽管该反应是化学计量的。我们已经注意到后过渡金属络合物，通过它，二氮和二氢都被结合和活化。我们的目的是发展固氮催化循环，其中二氢用于质子化，金属络合物上的配位二氮的还原。本文研究了含三齿二酰胺基的后过渡金属配合物的合成和反应性（NSN型），二氨基/膦（NPN型）和二氨基/胺（NNNA型）配体，虽然不能分离出双氮配合物，但反应溶液的IR光谱显示形成了[Ru（NSN）（PMe_3）_2（N → N）]，但双氮的氢化没有进行。我们发现了二硝基甲苯的等电子分子苯甲腈的催化氢化反应， 关于我们 另一方面，多金属硫原子簇化学与固氮酶活性中心的关系也引起了人们的广泛关注。我们一直致力于在分子水平上构筑多核金属-硫反应中心，并对反应中心的结构进行精细的控制。（M=Ru，Rh，Ni，Pd，Pt）核的制备及其反应性能的研究表明，肼的缩合反应可生成氨和二氮，当[（Cp^^*Mo）_3（η^3-S）_4RuH_2（PAr_3）][Mo_3NiS_4]簇合物对炔酸环化为烯醇内酯的反应具有催化活性，而单核Ni配合物对炔酸环化为烯醇内酯的反应则没有催化活性，虽然在钌上结合双氮的[Mo_3RuS_4]簇合物的制备尝试失败，但[Mo_3NiS_4]簇合物对炔酸环化为烯醇内酯的反应具有催化活性，[Mo_3MS_4]（M=Pd，Ru）簇合物对氨基炔的分子内氢胺化反应表现出比单核Pd或Ru配合物更高的催化活性。少

Recently we have found the novel reaction of a tungsten dinitrogen complex with acidic ruthenium η^2-dihydrogen complexes to form ammonia under mild conditions, although the reaction is stoichiometric.In this project, we have paid our attention to late transition metal complexes by which both dinitrogen and dihydrogen are bound and activated.Our purpose is to develop the nitrogen fixation catalytic cycle in which dihydrogen is used for protonation and reduction of the coordinated dinitrogen on a metal complex. We have investigated synthesis and reactivity of late transition-metal complexes containing tridentate diamidoAbloether(NSN-type), diamido/phosphine(NPN-type), and diamido/amine(NNNAype)ligands.Although dinitrogen complexes could not be isolated, the IR spectrum-of a reaction solution showed the formation of [Ru(NSN)(PMe_3)_2(N≡N)], but hydrogenation of dinitrogen did not proceed.However, we have found the catalytic hydrogenation of benzonitnle, an isoelectronic molecule of dinit … More rogen, by employing those metal complexes containing tridentate amido ligands.On the other hand, the chemistry of multimetallic sulfido clusters has been receiving much attention in relevance to the active sites of nitrogenase. We have long aimed at construction of polynuclear metal-sulfur reaction sites, the stnictures of which are carefully controlled at molecular levels.In this study, cubane-type clusters having a [Mo_3MS_4] (M=Ru, Rh, Ni, Pd, Pt)core were prepared and their reactivities were investigated.The disproportionation reaction of hydrazine proceeded to form ammonia and dinitrogen, when [(Cp^^*Mo)_3(η^3-S)_4RuH_2(PAr_3)](Ar=Ph, p-tolyl)was reacted with hydrazine.Although attempts to prepare[Mo_3RuS_4]clusters binding dinitrogen on ruthenium have failed, [Mo_3NiS_4]clusters showed novel catalytic activity for the cyclization of alkynoic acids to enol lactones, which was not catalyzed by mononuclear Ni complexes.Further, [Mo_3MS_4](M=Pd, Ru)clusters exhibited higher catalytic activity than mononuclear Pd or Ru complexes for the intramolecular hydroamination of aminoalkynes. Less