Heterometallic Ni–Pt Chini-Type Carbonyl Clusters: An Example of Molecular Random Alloy Clusters

The direct reactions of homometallic [Ni6(CO)12]2– and [Pt6(CO)12]2– Chini carbonyl clusters result in heterometallic Ni–Pt Chini-type clusters of the general formula [Pt6–xNix(CO)12]2– (x = 0–6). Their molecular structures have been determined by single-crystal X-ray diffraction (SC-XRD), showing a common octahedral (staggered, D3d) structure analogous to that of [Ni6(CO)12]2–, whereas [Pt6(CO)12]2– displays a trigonal-prismatic (eclipsed, D3h) structure. This structural change after replacing one single Pt with Ni may be classified as an alloying effect, and it has been theoretically investigated by DFT methods. Spectroscopic (IR and 195Pt and 13C NMR) and ESI-MS studies indicate that mixtures of [Pt6–xNix(CO)12]2– (x = 0–6) clusters are actually present in solution, whose compositions may be varied in an almost continuous way. Thus, they may be viewed as random alloy clusters whose overall compositions depend on the stoichiometry of the reagents.


Figure S13
IR spectrum (ν CO region) recorded in CH 3

Figure S16
Isotopic pattern of the peak at m/z 492 of the ESI-MS spectrum in CH 3 CN (ES-) of [NBu 4 ] 2 [Pt 6-S13

Figure S17
Isotopic pattern of the peak at m/z 547 of the ESI-MS spectrum in CH 3 CN (ES-) of [NBu 4 ] 2 [Pt 6-S14

Figure S18
Isotopic pattern of the peak at m/z 614 of the ESI-MS spectrum in CH 3 CN (ES-) of [NBu 4 ] 2 [Pt 6-S15

Figure S19
Isotopic pattern of the peak at m/z 683 of the ESI-MS spectrum in CH 3 CN (ES-) of [NBu 4 ] 2 [Pt 6-S16

Figure S20
Isotopic pattern of the peak at m/z 697 of the ESI-MS spectrum in CH 3 CN (ES-) of [NBu 4 ] 2 [Pt 6-S17

Figure S21
Isotopic pattern of the peak at m/z 1749 of the ESI-MS spectrum in CH 3

Figure S29
Isotopic pattern of the peak at m/z 344 of the ESI-MS spectrum in CH 3

Figure S30
Isotopic pattern of the peak at m/z 412 of the ESI-MS spectrum in CH 3

Figure S31
Isotopic pattern of the peak at m/z 480 of the ESI-MS spectrum in CH 3

Figure S32
Isotopic pattern of the peak at m/z 521 of the ESI-MS spectrum in CH 3

Figure S33
Isotopic pattern of the peak at m/z 930 of the ESI-MS spectrum in CH 3

Figure S34
Isotopic pattern of the peak at m/z 1068 of the ESI-MS spectrum in CH 3

Figure S35
Isotopic pattern of the peak at m/z 1202 of the ESI-MS spectrum in CH 3

Figure S36
Isotopic pattern of the peak at m/z 1338 of the ESI-MS spectrum in CH 3

Figure S46
Comparison of (top) the simulated 195

Figure S52
Triangle exchange reactions between [Pt 6-x Ni x (CO) 12 ] 2-(x = 0 -6) clusters.  Structures were solved by direct methods and refined by full-matrix least-squares based on all data using F 2 . 2 Hydrogen atoms were fixed at calculated positions and refined by a riding model. All non-hydrogen atoms were refined with anisotropic displacement parameters, unless otherwise stated.

Computational details with figures and tables
Full geometry optimizations, optimizations with selected constrained internal coordinates and single-point calculations were carried out in vacuo using the hybrid meta-GGA DFT functional TPSS0, with 25% HF exchange, 3 in combination with Ahlrichs' def-2 TZVP basis set, with relativistic ECP for Pt. 4 The "restricted" approach was used in all the cases. Calculations were performed with the ORCA 4.2.0 software. 5 Cartesian coordinates of the DFT-optimized structures are collected in a separated .xyz file.

Figure S57
Relative energy variations of clusters 1 and 2 on changing the dihedral angle defining the relative position of the two {M 3 } triangles. Solid line: single point calculations. Dashed line: geometry optimizations with constrained inter-triangular dihedral angles.