There has been considerable interest in the deposition of highly conductive ruthenium and RuO 2 thin films for use in the manufacture of integrated circuits. Various ruthenium organometallic complexes have been proposed as CVD source reagents, including ruthenocene [1] and its alkyl substituted derivative complexes such as Ru(C 5 H 4 Et) 2 , [2] and metal carbonyl complexes such as Ru(CO) 3 (C 6 H 8 ), (C 6 H 8 = 1,3-cyclohexadiene), [3] Ru(CO) 4 (hfb), [4] (hfb = hexafluoro-2-butyne), [(C 5 H 5 )Ru(CO) 2 ] 2 , and Ru 3 (CO) 12 ; [5] tris-b-diketonate complexes such as Ru(acac) 3 , Ru(tfac) 3 , and Ru(tmhd) 3 , (tfac = 1,1,1-trifluoro-2,4-pentandionate and tmhd = 2,2,6,6-tetramethyl-3,5-heptanedione); [6] alkenyl and alkene complexes such as bis(2,4-dimethylpentadienyl)-ruthenium, bis(2,4-dimethyloxapentadienyl)ruthenium, [7] (g 6 -C 6 H 6 )Ru(g 4 -C 6 H 8 ), and Ru(C 3 H 5 ) 2 (COD), (COD = 1,4-cyclooctadiene). [8] Although some of these compounds are liquids, or relatively volatile low-melting point solids, which are amenable to sublimation for gas-phase transport into the CVD reactor, most of them possess fairly high melting points, high decomposition temperatures, or are thermally unstable and react with moisture and oxygen when exposed to air, making them difficult to store and handle.Accordingly, there is an urgent need for low-melting point, highly volatile, and relatively stable ruthenium compounds as source reagents for various CVD applications, such as the preparation of ruthenium metal bottom electrodes and barrier layers for integrated circuits. [9] More specifically, these CVD source materials may find applications in fabricating the BST-based Gb-scale dynamic random access memory (DRAM), and for manufacturing Ru pillars and Ta 2 O 5 /Ru capacitors in embedded DRAM technology. [10] The complexes which possess the required physical properties are a series of new Ru II complexes with the general formula Ru(CO) 2 (diketonate) 2 . These complexes are easily prepared in excellent yields from the direct reaction of excess b-diketone, such as hexafluoroacetylacetone (hfacH) or 2,2,6,6-tetramethyl-3,5-heptanedione (tmhdH), and Ru 3 (CO) 12 in a sealed stainless steel autoclave at an elevated temperature, according to a modification of the method for Ru(CO) 2 (acac) 2 . [11] The resulting products are purified by reduced-pressure distillation or vacuum sublimation, followed by recrystallization from methanol at ±20 C.The 13 C NMR spectra for the complexes Ru(CO) 2 (hfac) 2 (1) and Ru(CO) 2 (tmhd) 2 (2) show the presence of one signal for Ru-bound CO ligands and two distinct CO signals from the b-diketonate ligands, suggesting that the molecule consists of an octahedral structure composed of two b-diketonate ligands and two CO ligands arranged in the cis-disposition. The structure of these complexes is further confirmed by single-crystal X-ray analysis of 1 (Fig. 1). The Ru±CO distances (1.896(3) and 1.900(4) ) are slightly shorter than that of the parent carbonyl complex Ru 3 (CO) 12 (av. 1.93 ). [12] The Ru±...

Metal carbonyl complex Os 3 (CO) 12 reacts with a hexane solution of (thd)H, thd ) 2,2dimethyl-3,5-heptanedionate, in a sealed autoclave at 190 °C to afford the Os 4 metal chain complex [Os 2 (CO) 5 (thd) 2 ] 2 (1), isolated from repeated recrystallization in air. Treatment of 1 with CO at room temperature gives the Os 2 metal complex [Os 2 (CO) 6 (thd) 2 ] (2) through reversible cleavage of the central Os-Os bond. EHMO calculation has been carried out to explain the involvement of a short-long-short Os-Os‚‚‚Os-Os array.