Unsymmetrical Coordination of Bipyridine in Three-Coordinate Gold(I) Complexes
Unsymmetrical Coordination of Bipyridine in Three-Coordinate Gold(I) Complexes
复制标题
DOI：
10.1021/acs.inorgchem.0c00138
复制
发表时间：
2020-03-16
影响因子：
4.6
通讯作者：
Balch, Alan L.
中科院分区：
文献类型：
--
作者：
Luong, Lucy M. C.;Aristov, Michael M.;Balch, Alan L.
用晶体学和计算方法研究了金(I)与2,2′-联吡啶（bipy）在某些平面三坐标阳离子中的不对称配位。盐[(Ph P-3)Au(bipy)]XF6 （X = P, As, Sb）形成一个同构系列，其中Au- n距离差在0.241(2)~ 0.146(2)埃之间。还发现了[(Ph3P)Au(bipy)]AsF6的第二个多晶型。两种多晶型表现出相似的结构。盐类[(Et3P)Au(bipy)]XF6（X = P, As, Sb）形成第二个同位结构系列。在这个系列中，bipy配体的不对称配位得到了维持，但金离子在两个不均匀分布的位置上是无序的，这使得阳离子的整体结构非常相似。虽然许多平面三坐标金(I)配合物具有强发光，但盐[(R3P)-Au(bipy)]XF6 （R = Ph或Et； X = P, As, Sb）在固体或溶液中不发光。计算研究表明，[(Et3P)Au(bipy)]（+）的完全对称结构的能量比观测到的不对称结构高7 kJ/mol，最好描述为两种极限不对称几何之间的过渡态。利用“12电子规则”，用自然共振理论（NRT）计算检验了Au-N键。主要的路易斯结构是金原子上有5对孤电子对，P原子上有1个键，这导致了一个饱和的（12个电子）金中心，从而抑制了金原子和氮原子之间任何经典的2个e（-）键的形成。相反，氮原子可能将孤电子对提供给空的Au-P反键轨道，从而形成三中心四电子（3c/4e） P-Au-N键。还制备了双核配合物[mu(2)-bipy(AuPPh3)(2)](PF6)(2)，并证明两个金离子之间存在亲光相互作用，两个金离子相距3.0747(3)埃。尽管有亲光相互作用，这个双核复合物并不发光。
The unsymmetrical coordination of gold(I) by 2,2'-bipyridine (bipy) in some planar, three-coordinate cations has been examined by crystallographic and computational studies. The salts [(Ph P-3)Au(bipy)]XF6 (X = P, As, Sb) form an isomorphic series in which the differences in Au-N distances range from 0.241(2) to 0.146(2) angstrom. A second polymorph of [(Ph3P)Au(bipy)]AsF6 has also been found. Both polymorphs exhibit similar structures. The salts [(Et3P)Au(bipy)]XF6(X = P, As, Sb) form a second isostructural series. In this series the unsymmetrical coordination of the bipy ligand is maintained, but the gold ions are disordered over two unequally populated positions that produce very similar overall structures for the cations. Although many planar, three-coordinate gold(I) complexes are strongly luminescent, the salts [(R3P)-Au(bipy)]XF6 (R = Ph or Et; X = P, As, Sb) are not luminescent as solids or in solution. Computational studies revealed that a fully symmetrical structure for [(Et3P)Au(bipy)](+) is 7 kJ/mol higher in energy than the observed unsymmetrical structure and is best described as a transition state between the two limiting unsymmetrical geometries. The Au-N bonding has been examined by natural resonance theory (NRT) calculations using the "12 electron rule". The dominant Lewis structure is one with five lone pairs on Au and one bond to the P atom, which results in a saturated (12 electron) gold center and thereby inhibits the formation of any classical, 2 e(-) bonds between the gold and either of the bipy nitrogen atoms. The nitrogen atoms may instead donate a lone pair into an empty Au-P antibonding orbital, resulting in a three-center, four-electron (3c/4e) P-Au-N bond. The binuclear complex, [mu(2)-bipy(AuPPh3)(2)](PF6)(2), has also been prepared and shown to have an aurophillic interaction between the two gold ions, which are separated by 3.0747(3) angstrom. Despite the aurophillic interaction, this binuclear complex is not luminescent.