The reduction of tetraphenyldiphosphine with two differently substituted samarocenes(II) proceeds via different pathways. With [SmCp* 2 (THF) 2 ] (Cp* = η 5 -C 5 Me 5 ), the reaction had been known to result in the THF ring-opening product, [SmCp* 2 (O(CH 2 ) 4 PPh 2 )], 3, owing to the instability of phosphido complex [SmCp* 2 (PPh 2 )] in the presence of THF. Complex 3 crystallizes from apolar solvents as dimeric or polymeric polymorph with butoxo-phosphine bridging ligands in both cases. In contrast, the phosphide [SmCp″ 2 (PPh 2 )] (Cp′′ = η 5 -1,3-C 5 H 3 t Bu 2 ), 5, is not prone to ring-opening owing to insufficient space in the Sm coordination sphere for a THF ligand. Product 5 is inevitably accompanied by homoleptic complex [SmCp″ 3 ] 6 and dinuclear mixed-valent complex [Sm III Cp″ 2 (μ-PPh 2 ) 2 Sm II Cp″] 7 as the further products of redox transformations and ligand exchange. The formation of 5−7 is rationalized by a sequence of initial coordination of one or two {Sm II Cp″ 2 } fragments by P atoms and reductive elimination of PPh 2 • or Cp″• radicals. Further reaction with another equivalent of [SmCp″ 2 ] results in the trapping the radicals and formation of all three products.

Interest in iridium and platinum has been steadily encouraged due to such unique properties as exceptional chemical inertia and corrosion resistance, high biological compatibility, and mechanical strength, which are the basis for their application in medical practice. Metal-organic chemical vapor deposition (MOCVD) is a promising method to fabricate Ir and Pt nanomaterials, multilayers, and heterostructures. Its advantages include precise control of the material composition and microstructure in deposition processes at relatively low temperatures onto non-planar substrates. The development of MOCVD processes is inextricably linked with the development of the chemistry of volatile precursors, viz., specially designed coordination and organometallic compounds. This review describes the synthesis methods of various iridium and platinum precursors, their thermal properties, and examples of the use of MOCVD, including formation of films for medical application and bimetallics. Although metal acetylacetonates are currently the most widely used precursors, the recently developed heteroligand Ir(I) and Pt(IV) complexes appear to be more promising in both synthetic and thermochemical aspects. Their main advantage is their ability to control thermal properties by modifying several types of ligands, making them tunable to deposit films onto different types of materials and to select a combination of compatible compounds for obtaining the bimetallic materials.

The first monomeric anhydrous scandium tris(8-quinolinolate) complex 1 with the 2-amino-8-quinolinolate ligands and the Sc(2)Q(6) dinuclear complex 2 with the unsubstituted 8-quinolinolate ligands have been synthesized and characterized by X-ray analysis and DFT calculations. The intramolecular hydrogen bonds appear to be responsible for the unique monomeric structure of complex 1. The DFT-based analysis of the electron density topology reveals the (3,-1) critical points corresponding to the O···H and N···H bonds. The two scandium atoms in compound 2 are inequivalent due to different ligand surroundings. They are coordinated by seven (5O, 2N) and eight (4O, 4N) ligand atoms. The increase in the coordination number is accompanied by a decrease in the positive charge of the metal atom as evidenced by the DFT calculations.