School of Chemistry, University of Bristol, Bristol, UK BS8 1TS.
Dalton Trans. 2009 Oct 28(40):8724-36. doi: 10.1039/b910108j. Epub 2009 Aug 28.
The reaction of a mixture of the sodium salts of dihydrobis(4-ethyl-3-methyl-5-thioxo-1,2,4-triazolyl)borate, NaBt, and hydrotris(4-ethyl-3-methyl-5-thioxo-1,2,4-triazolyl)borate, NaTt, with [{Rh(cod)(mu-Cl)}2] gave [Rh(cod)Bt] and [Rh(cod)Tt], which separately react with CO gas to give the unstable dicarbonyl [Rh(CO)2Bt] and an equilibrium mixture of two isomers of [Rh(CO)2Tt] and [(RhTt)2(mu-CO)3], respectively. Tertiary phosphorus donor ligands react with the mixture of [Rh(CO)2Tt] and [(RhTt)2(mu-CO)3] to give [Rh(CO)(PR3)Tt] (R = Cy, NMe(2), Ph or OPh) and [Rh{P(OPh)3}2Tt] in which rhodium is bound to two sulfur atoms of the scorpionate ligand; the B-H bond is directed towards the metal to give an agostic-like B-H...Rh interaction. Dinuclear [(RhTt)2(mu-CO)3] has kappa3[S3]-bound Tt ligands with a rhodium-rhodium bond bridged by three carbonyls. In solution the mononuclear Tt complexes undergo rapid dynamic interchange of the three thioxotriazolyl rings, probably via kappa3[S3]-coordinated intermediates. The monocarbonyls [Rh(CO)(PR3)Tt] (R = Cy, NMe2 or Ph) react with two equivalents of [Fe(eta-C5H5)2][PF6] in the presence of triethylamine to give the monocationic rhodaboratranes [Rh(CO)(PR3){B(taz)3}]+, with boron NMR spectroscopy providing evidence for the boron-rhodium bond. In the solid state, rhodium is bound to the three sulfur atoms and the boron of the B(taz)3 fragment, forming a tricyclo[3.3.3.0] cage. The phosphine is trans to the Rh-B bond, the long Rh-P bond indicating a pronounced trans influence for the coordinated boron. The cation [Rh(CO)(PPh3){B(taz)3}]+ reacts with [NBu(n)(4)]I to give [Rh(PPh3)I{B(taz)3}], in which the halide is trans to the Rh-B bond, and a second species, possibly [Rh(CO)I{B(taz)3}]. The dirhodaboratrane [Rh2(PCy3){B(taz)3}2][PF6]2, a minor byproduct in the synthesis of [Rh(CO)(PCy3){B(taz)3}][PF6], has a distorted square pyramidal rhodium atom with a vacant site trans to the Rh-B bond. The second metal has four coordination sites filled by the sulfur and boron atoms of a second B(taz)3 unit, the remaining octahedral sites occupied by two of the sulfur atoms of the first B(taz)3 unit which therefore bridges the two rhodium atoms.
硼酸盐与氢三（4-乙基-3-甲基-5-噻唑基）硼酸盐的混合物与[{Rh(cod)(mu-Cl)}2]反应，得到[Rh(cod)Bt]和[Rh(cod)Tt]，它们分别与 CO 气体反应生成不稳定的二羰基[Rh(CO)2Bt]和[Rh(CO)2Tt]的两种异构体的平衡混合物和[(RhTt)2(mu-CO)3]。三价磷供体配体与[Rh(CO)2Tt]和[(RhTt)2(mu-CO)3]的混合物反应，生成[Rh(CO)(PR3)Tt](R = Cy、NMe(2)、Ph 或 OPh)和[Rh{P(OPh)3}2Tt]，其中铑与螯合配体的两个硫原子结合;B-H 键指向金属，形成类桥接的 B-H…Rh 相互作用。双核[(RhTt)2(mu-CO)3]具有κ3[S3]-结合的 Tt 配体，通过三个羰基桥接的铑-铑键。在溶液中，单核 Tt 配合物通过κ3[S3]-配位的中间体迅速进行三个噻唑基环的动态交换。单核羰基[Rh(CO)(PR3)Tt](R = Cy、NMe2 或 Ph)与[Fe(eta-C5H5)2][PF6]的两倍当量在三乙胺存在下反应，生成单核阳离子[Rh(CO)(PR3){B(taz)3}]+，硼核磁共振光谱提供了硼-铑键的证据。在固态中，铑与三个硫原子和 B(taz)3 片段的硼结合，形成一个三环[3.3.3.0]笼。膦与 Rh-B 键处于反式，长的 Rh-P 键表明配位硼具有明显的反式影响。阳离子[Rh(CO)(PPh3){B(taz)3}]+与[NBu(n)(4)]I 反应生成[Rh(PPh3)I{B(taz)3}]，其中卤素处于 Rh-B 键的反式位置，还有第二种可能的物种[Rh(CO)I{B(taz)3}]。二硼酸盐[Rh2(PCy3){B(taz)3}2][PF6]2是[Rh(CO)(PCy3){B(taz)3}][PF6]合成中的次要副产物，其具有扭曲的四方锥铑原子，空位处于 Rh-B 键的反式位置。第二个金属具有四个配位位点，由第二个 B(taz)3 单元的硫和硼原子填充，剩余的八面体位点由第一个 B(taz)3 单元的两个硫原子占据，因此桥接两个铑原子。
