Conradie Jeanet, Torstensen Kristian, Pyykkö Pekka, Ghosh Abhik
Department of Chemistry, UiT─The Arctic University of Norway, N-9037 Tromsø, Norway.
Department of Chemistry, University of the Free State, P.O. Box 339, Bloemfontein 9300, Republic of South Africa.
Inorg Chem. 2025 Jul 28;64(29):15098-15106. doi: 10.1021/acs.inorgchem.5c02000. Epub 2025 Jul 12.
A wide-ranging density functional theory (DFT) survey of monovalent Group 13 complexes (trielylenes) has afforded detailed insights into periodic trends in these compounds. Five classes of neutral complexes were examined, based on β-diketiminate, bis(imino)carbazolate (pincer), hydrotrispyrazolylborate, cyclopentadienide, and monocoordinate aryl ligands. Also examined was a set of ,'-diaryl-1,4-diazabutadiene dianion-coordinated triel(I) anions. In general, the ionization potential of the Ga-based lone pairs was found to be nearly 1 eV or more higher than that of Al-based lone pairs in similar species; the corresponding IPs for In were found to hover around the values calculated for Ga. This general trend may be thought of as an electronic manifestation of scandide contraction, which results in stabilization of the 4s and 4p subshells due to poor screening by the filled 3d subshell. Only for the aryl series was this effect found to be quite muted, apparently because these complexes do not harbor a genuine metal-based lone pair. Instead, the highest occupied molecular orbital (HOMO) consists of a metal-carbon σ-antibonding orbital, spread over multiple atoms. The calculations also underscore the major role of the supporting ligand in modulating the electronic properties of trielylenes and help explain why certain species such as Al(I) bis(imino)carbazolates might not be stable enough to permit isolation.
对一价13族配合物（三乙撑）进行的广泛密度泛函理论（DFT）研究，深入洞察了这些化合物的周期性趋势。基于β-二酮亚胺、双（亚氨基）咔唑（钳形）、氢三吡唑硼酸酯、环戊二烯基和单配位芳基配体，研究了五类中性配合物。还研究了一组由,'-二芳基-1,4-二氮杂丁二烯二价阴离子配位的三价铊（I）阴离子。一般来说，在类似物种中，发现基于镓的孤对电子的电离势比基于铝的孤对电子的电离势高近1 eV或更多；发现铟的相应电离势在为镓计算的值附近波动。这种一般趋势可被认为是钪系收缩的电子表现，由于充满的3d子壳层屏蔽作用差，导致4s和4p子壳层稳定。仅对于芳基系列，发现这种效应相当不明显，显然是因为这些配合物没有真正基于金属的孤对电子。相反，最高占据分子轨道（HOMO）由一个扩展到多个原子的金属-碳σ反键轨道组成。计算还强调了支撑配体在调节三乙撑电子性质方面的主要作用，并有助于解释为什么某些物种，如铝（I）双（亚氨基）咔唑可能不够稳定而无法分离。
