From M 6 to M 12 , M 19 and M 38 molecular alloy Pt-Ni carbonyl nanoclusters: selective growth of atomically precise heterometallic nanoclusters.

Heterometallic Chini-type clusters [Pt 6- x Ni x (CO) 12 ] 2- ( x = 0-6) were obtained by reactions of [Pt 6 (CO) 12 ] 2- with Ni-clusters such as [Ni 6 (CO) 12 ] 2- , [Ni 9 (CO) 18 ] 2- and [H 2 Ni 12 (CO) 21 ] 2- , or from [Pt 9 (CO) 18 ] 2- and [Ni 6 (CO) 12 ] 2- . The Pt/Ni composition of [Pt 6- x Ni x (CO) 12 ] 2- ( x = 0-6) depended on the nature of the reagents employed and their stoichiometry. Reactions of [Pt 9 (CO) 18 ] 2- with [Ni 9 (CO) 18 ] 2- and [H 2 Ni 12 (CO) 21 ] 2- , as well as reactions of [Pt 12 (CO) 24 ] 2- with [Ni 6 (CO) 12 ] 2- , [Ni 9 (CO) 18 ] 2- and [H 2 Ni 12 (CO) 21 ] 2- , afforded [Pt 9- x Ni x (CO) 18 ] 2- ( x = 0-9) species. [Pt 6- x Ni x (CO) 12 ] 2- ( x = 1-5) were converted into [Pt 12- x Ni x (CO) 21 ] 4- ( x = 2-10) upon heating in CH 3 CN at 80 °C, with almost complete retention of the Pt/Ni composition. Reaction of [Pt 12- x Ni x (CO) 21 ] 4- ( x ≈ 8) with HBF 4 ·Et 2 O afforded the [HPt 14+ x Ni 24- x (CO) 44 ] 5- ( x ≈ 0.7) nanocluster. Finally, [Pt 19- x Ni x (CO) 22 ] 4- ( x = 2-6) could be obtained by heating [Pt 9- x Ni x (CO) 18 ] 2- ( x = 1-3) in CH 3 CN at 80 °C, or [Pt 6- x Ni x (CO) 12 ] 2- (2-4) in DMSO at 130 °C. The molecular structures of these new alloy nanoclusters have been determined by single crystal X-ray diffraction. The site preference of Pt and Ni within their metal cages has been computationally investigated. The electrochemical and IR spectroelectrochemical behavior of [Pt 19- x Ni x (CO) 22 ] 4- ( x = 3.11) has been studied and compared to the isostructural homometallic nanocluster [Pt 19 (CO) 22 ] 4- .