(ARYNE)METALLOCENE-DERIVED AND (ALKYNE)METALLOCENE-DERIVED DIMETALLIC ZIRCONIUM ALUMINUM COMPLEXES CONTAINING PLANAR-TETRACOORDINATE CARBON
(ARYNE)METALLOCENE-DERIVED AND (ALKYNE)METALLOCENE-DERIVED DIMETALLIC ZIRCONIUM ALUMINUM COMPLEXES CONTAINING PLANAR-TETRACOORDINATE CARBON
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DOI：
10.1021/om00059a014
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发表时间：
1992-11-01
期刊：
影响因子：
2.8
通讯作者：
LANGHAUSER, F
中科院分区：
文献类型：
--
作者：
ERKER, G;ALBRECHT, M;LANGHAUSER, F
可将刘易斯酸性主族金属的化合物X-[M2]加到反应性很强的炔-过渡金属络合物（η 2-RC=CR）[M1]上，形成含有平面四配位碳原子的二金属双环有机金属化合物[M1]（μ-，η 1：η 2-RCCR）（μ-X）[M2]，其通过特定金属/配体组合的σ-供体/π-受体组合性质而稳定。该一般合成方案已用于通过使例如（η 2-芳炔）-（PMe 3）Z4 Cp 2（12）与2摩尔当量的氢化二异丁基铝反应来制备这种平面四配位碳络合物。初始Me3P.HAI（iBU）2加合物形成产生反应性（η 2-芳炔）ZrCP 2中间体，其然后被另外的氢化铝试剂捕获以产生化学稳定的络合物Cp 2 Zr（μ-η 1：η 2-C6 H4）（μ-H）Al（iBU）2（14 a）。 配合物14 a的晶体属于空间群P2（1）/n，晶胞参数a = 16.749（3）埃，B = 13.833（1）埃，c = 20.178（2）埃，β = 90.74（1）度，R = 0.088，R（w）= 0.093。它在二金属双环骨架的桥头位置含有平面四配位碳中心[C（2）]，其与两个碳原子键合[d（C（2）-C（1））= 1.37（2）埃，d（C（2）-C（3））= 1.41（1）埃]，锆[d（C（2）-Zr）= 2.430（8）埃]，和铝原子[d（C（2）-Al）= 2.09（1）埃，所有值在两个独立分子上平均，围绕C（2）的键角之和为360度]。12与三甲基铝反应得到类似结构的CP 2 Zr（mu-eta 1：eta 2-CrH 4）（mu-CH 3）AlMe 2 COMPleX 14 b;用三乙基铝处理12得到CP 2 Zr（mu-eta 1：eta 2-C6 H4））（mu-CH 2CH 3）AlEt 2（14 c）。配合物14 B的结构经X射线衍射分析，空间群为P2（1）/n，a = 9.151（1）埃，B = 14.022（1）埃，c = 14.415（1）埃，β = 104.56（1）度，R = 0.042，R（w）= 0.057。同样，碳原子C（2）是平面四配位的[d（C（2）-C（1））= 1.383（4），d（C（2）-C（3））= 1.423（5），d（C（2）-Zr）= 2.481（3），d（C（2）-Al）= 2.082（3）埃; C（2）处的键角之和为360度]。用于制备二金属双环“反范霍夫/勒贝尔化合物”的一般合成方案也可应用于从稳定的（η 2-炔）金属茂络合物开始的反应序列。因此，（η 2-环己炔）（PMe 3）ZrCp 2（11 a）或（η 2-二苯基乙炔）（PMeOZrCp 2（11b）与过量的三甲基铝反应得到相应的CP 2 Zr（μ-η 1：η 2-RCCR）（μ-CH 3）AlMe 2产物（7 d，e）。（二苯乙炔）茂金属络合物11b与9-BBN和三乙基硼的混合物之间的反应以低收率产生Cp 2 Zr（μ-η 1：η 2-PhCCPh）（μ-H）BEt 2（15）。
Compounds X-[M2] of Lewis acidic main group metals can be added to very reactive alkyne-transition metal complexes (eta2-RC=CR)[M1] to form dimetallabicyclic organometallic compounds [M1](mu-,eta1:eta2-RCCR)(mu-X)[M2] containing a planar-tetracoordinate carbon atom, which is stabilized by the combined sigma-donor/pi-acceptor properties of the specific metal/ligand combination. This general synthetic scheme has been used to prepare such planar-tetracoordinate carbon complexes by reacting e.g. (eta2-aryne)-(PMe3)Z4Cp2 (12) with 2 molar equiv of diisobutylaluminum hydride. Initial Me3P.HAI(iBU)2 adduct formation generates the reactive (eta2-aryne)ZrCP2 intermediate, which is then trapped by additional hydridoaluminum reagent to yield the thermodynamically stable complex Cp2Zr(mu-eta1:eta2-C6H4)(mu-H)Al(iBU)2 (14a). Complex 14a crystallizes in space group P2(1)/n with cell parameters a = 16.749 (3) angstrom, b = 13.833 (1) angstrom, c = 20.178 (2) angstrom, beta = 90.74 (1)-degrees, R = 0.088, and R(w) = 0.093. It contains a planar-tetracoordinate carbon center [C(2)] at the bridgehead position of the dimetallabicyclic framework which is bonded to two carbon atoms [d(C(2)-C(l)) = 1.37 (2) angstrom, d(C(2)-C(3)) = 1.41 (1) angstrom], the zirconium [d(C(2)-Zr) = 2.430 (8) angstrom], and the aluminum atom [d(C(2)-Al) = 2.09 (1) angstrom, all values averaged over the two independent molecules, the sum of bonding angles around C(2) is 360-degrees]. The reaction between 12 and trimethylaluminum gave the analogously structured CP2Zr(mu-eta1:eta2-CrH4)(mu-CH3)AlMe2 COMPleX 14b; treatment of 12 with triethylaluminum furnished CP2Zr(mu-eta1:eta2-C6H4))(mu-CH2CH3)AlEt2 (14c). Complex 14b was characterized by X-ray diffraction (space group P2(1)/n, a = 9.151 (1) angstrom, b = 14.022 (1) angstrom, c = 14.415 (1) angstrom, beta = 104.56 (1)-degrees, R = 0.042, R(w) = 0.057). Again, carbon atom C(2) is planar-tetracoordinate [d(C(2)-C(l)) = 1.383 (4), d(C(2)-C(3)) = 1.423 (5), d(C(2)-Zr) = 2.481 (3), d(C(2)-Al) = 2.082 (3) angstrom; the sum of bonding angles at C(2) is 360-degrees]. The general synthetic scheme for the preparation of dimetallabicyclic "anti-van't Hoff/LeBel compounds" can also be applied to reaction sequences starting from stable (eta2-alkyne)metallocene complexes. Thus, the reaction of (eta2-cyclohexyne)(PMe3)ZrCp2 (11a) or (eta2-diphenylacetylene)(PMeOZrCp2 (11b) with excess trimethylaluminum gave the respective CP2Zr(mu-eta1:eta2-RCCR) (mu-CH3)AlMe2 products (7d,e). The reaction between the (tolane)metallocene complex 11b with a mixture of 9-BBN and triethylboron produced Cp2Zr(mu-eta1:eta2-PhCCPh)(mu-H)BEt2 (15) in low yield.