Syntheses And Structures Of Some Ruthena-and Platinaboranes

Boron cluster chemistry is an interesting and increasingly developing field of study that includes neutral boranes and their anions, metallaboranes, carboranes and metallacarboranes, main group heteroboranes and their metal derivatives. These compounds have provided a lot of interesting potential applications, including solvent extraction, catalysis, boron neutron capture therapy (BNCT) of tumors, nonlinear optics, liquid crystals, ion-selective electrodes, electrolytes for storage batteries and host-guest chemistry. Meanwhile, the topological theory and polyhedral skeletal electron-pair theory propelled the further development of borane chemistry and expanded the scope of structural chemistry. People have been synthesizing large number of boron clusters and modifying their bonding and reaction rules, in the hope of obtaining new boron clusters with special applications.Therefore, it is of interest to continue studying the syntheses and structures of new borane derivatives.This thesis describes the research on metallaborane clusters obtained from the reactions of [PtCl2(PPh3)2] or [RuCl2(PPh3)3] and closo-[B₁₀H₁₀]^2- under different conditions.The four sections of this thesis are as follows:In chapter 1, a general review is given to introduce the development of boron cluster chemistry in particular that of closo-[B₁₀H₁₀]^2-, the structures of the transition metal metallaborane clusters.In chapter 2, the reactions of [PtCl2(PPh3)2] with closo-[B₁₀H₁₀]^2- in refluxing MeOH, tBuOH and CH3COSH/CH2Cl2, respectively, are described. The three eleven-vertex platinaborane products: [(PPh3)2PtB₁₀H10-9-(OCH3)-11-(H)0.5(OCH3)0.5] (1) ,[(PPh3)2PtB₁₀H10-9,10-(H0.7Cl0.3)2] (3),[(PPh3)2PtB₁₀H11-11-OOCCH3]·CH2Cl2 (4). The 1,3,4 clusters have nido 11-vertex {PtB₁₀} polyhedral skeleton, in which the Pt atom stay in the open PtB4 face, while connecting with four B atoms and two PPh3 ligands. A diplatinaborane [(PPh3)2Pt(μ-PPh2)PtB9H6-3,9,11-(OMe)3] (2) is obtained from the reaction of [PtCl2(PPh3)2] with closo-[B₁₀H₁₀]^2- in MeOH under solvothermal condition. Compound 2 has a nido 11-vertex {Pt2B9} polyhedral skeleton, in which two Pt atoms stay in adjacent position on the open Pt2B3 face and further bridged by a PPh2 group. Each Pt atom coordinates to three B atoms and a P atom of the PPh3 ligand. Some of these products are characterized by IR, NMR, elemental analysis and single-crystal X-ray analyses.In chapter 3, we studied the reactions of [RuCl2(PPh3)3] and closo-[B₁₀H₁₀]^2- in different solutions. The reaction in refluxing CH3CH2OH affords an anionic ruthenaborane cluster: [Et4N][(PPh3)RuClB10H8(OEt)2] (5). Compound 5 reacted with 2,2'-bipyridine to afford the ruthenaborane cluster [(bpy)2RuB10H8(OEt)2] (6). Both 5 and 6 are characterized by IR, NMR and single-crystal X-ray analyses. The clusters 5 and 6 are based on a closo-type 1:2:4:2:2 {RuB10} stack with the metal occuping the unique six-connected apical position and can be considered as having isocloso structures derived from the complete capping of the open face of an arachano geometry to give a completely closed deltaheral cluster. [Et4N][(PPh3)2ClRuB12H12]·CHCl3 (7) was unexpectedly isolated from above the same reaction as a red air-stable solid, in cluster 7 the integrity of the closo-[B12H12]2- is maintained and the Ru(II) center coordinates to two PPh3, a Cl- and three exo-B-H units of the closo-[B12H12]2-, with a distorted octahedral geometry.In chapter 4, the reactions studied using Pt and Ru complexs and closo-[B₁₀H₁₀]^2- under different conditions are concluded as well as the structural characters of the products.