Zhao Yin, Schmalle Helmut W, Fox Thomas, Blacque Olivier, Berke Heinz
Department of Inorganic Chemistry, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
Dalton Trans. 2006 Jan 7(1):73-85. doi: 10.1039/b511797f. Epub 2005 Nov 23.
The tetrakis(trimethylphosphine) molybdenum nitrosyl hydrido complex trans-Mo(PMe(3))(4)(H)(NO) (2) and the related deuteride complex trans-Mo(PMe(3))(4)(D)(NO) (2a) were prepared from trans-Mo(PMe(3))(4)(Cl)(NO) (1). From (2)H T(1 min) measurements and solid-state (2)H NMR the bond ionicities of 2a could be determined and were found to be 80.0% and 75.3%, respectively, indicating a very polar Mo--D bond. The enhanced hydridicity of 2 is reflected in its very high propensity to undergo hydride transfer reactions. 2 was thus reacted with acetone, acetophenone, and benzophenone to afford the corresponding alkoxide complexes trans-Mo(NO)(PMe(3))(4)(OCHR'R'') (R' = R'' = Me (3); R' = Me, R'' = Ph (4); R' = R'' = Ph (5)). The reaction of 2 with CO(2) led to the formation of the formato-O-complex Mo(NO)(OCHO)(PMe(3))(4) (6). The reaction of with HOSO(2)CF(3) produced the anion coordinated complex Mo(NO)(PMe(3))(4)(OSO(2)CF(3)) (7), and the reaction with [H(Et(2)O)(2)][BAr(F)(4)] with an excess of PMe(3) produced the pentakis(trimethylphosphine) coordinated compound [Mo(NO)(PMe(3))(5)][BAr(F)(4)] (8). Imine insertions into the Mo-H bond of 2 were also accomplished. PhCH[double bond, length as m-dash]NPh (N-benzylideneaniline) and C(10)H(7)CH=NPh (N-1-naphthylideneaniline) afforded the amido compounds Mo(NO)(PMe(3))(4)[NR'(CH(2)R'')] (R' = R'' = Ph (9), R' = Ph, R'' = naphthyl (11)). 9 could not be obtained in pure form, however, its structure was assigned by spectroscopic means. At room temperature 11 reacted further to lose one PMe(3) forming 12 (Mo(NO)PMe(3))(3)[N(Ph)CH(2)C(10)H(6))]) with agostic stabilization. In a subsequent step oxidative addition of the agostic naphthyl C-H bond to the molybdenum centre occurred. Then hydrogen migration took place giving the chelate amine complex Mo(NO)(PMe(3))(3)[NH(Ph)(CH(2)C(10)H(6))] (15). The insertion reaction of 2 with C(10)H(7)N=CHPh led to formation of the agostic compound Mo(NO)(PMe(3))(3)[N(CH(2)Ph)(C(10)H(7))] (10). Based on the knowledge of facile formation of agostic compounds the catalytic hydrogenation of C(10)H(7)N=CHPh and PhN=CHC(10)H(7) with 2 (5 mol%) was tested. The best conversion rates were obtained in the presence of an excess of PMe(3), which were 18.4% and 100% for C(10)H(7)N=CHPh and PhN=CHC(10)H(7), respectively.
四（三甲基膦）亚硝酰氢化钼配合物反式 - Mo(PMe₃)₄(H)(NO) (2) 及相关氘化物配合物反式 - Mo(PMe₃)₄(D)(NO) (2a) 由反式 - Mo(PMe₃)₄(Cl)(NO) (1) 制备得到。通过²H T₁（1分钟）测量和固态²H NMR可确定2a的键离子性，发现其分别为80.0%和75.3%，表明Mo - D键具有很强的极性。2中增强的氢化物性质体现在其极易发生氢化物转移反应。因此，2与丙酮、苯乙酮和二苯甲酮反应，得到相应的醇盐配合物反式 - Mo(NO)(PMe₃)₄(OCHR'R'') （R' = R'' = 甲基 (3)；R' = 甲基，R'' = 苯基 (4)；R' = R'' = 苯基 (5)）。2与CO₂反应生成甲酰氧基配合物Mo(NO)(OCHO)(PMe₃)₄ (6)。与HOSO₂CF₃反应生成阴离子配位配合物Mo(NO)(PMe₃)₄(OSO₂CF₃) (7)，与[H(Et₂O)₂][BAr(F)₄]在过量PMe₃存在下反应生成五（三甲基膦）配位化合物[Mo(NO)(PMe₃)₅][BAr(F)₄] (8)。2的Mo - H键中也实现了亚胺插入反应。PhCH═NPh（N - 苄叉苯胺）和C₁₀H₇CH═NPh（N - 1 - 萘叉苯胺）反应得到酰胺化合物Mo(NO)(PMe₃)₄[NR'(CH₂R'')] （R' = R'' = 苯基 (9)，R' = 苯基，R'' = 萘基 (11)）。然而，9无法以纯形式获得，但其结构通过光谱手段确定。在室温下，11进一步反应失去一个PMe₃形成12（Mo(NO)PMe₃)₃[N(Ph)CH₂C₁₀H₆)]），具有agostic稳定作用。在随后的步骤中，agostic萘基C - H键向钼中心发生氧化加成。然后发生氢迁移，生成螯合胺配合物Mo(NO)(PMe₃)₃[NH(Ph)(CH₂C₁₀H₆)] (15)。2与C₁₀H₇N═CHPh的插入反应导致生成agostic化合物Mo(NO)(PMe₃)₃[N(CH₂Ph)(C₁₀H₇)] (10)。基于对agostic化合物易于形成的认识，测试了2（5 mol%）对C₁₀H₇N═CHPh和PhN═CHC₁₀H₇的催化氢化反应。在过量PMe₃存在下获得了最佳转化率，对于C₁₀H₇N═CHPh和PhN═CHC₁₀H₇分别为18.4%和100%。
