Platinum carbonyl clusters stabilized by Sn(ii)-based fragments: syntheses and structures of [Pt6(CO)6(SnCl2)2(SnCl3)4](4-), [Pt9(CO)8(SnCl2)3(SnCl3)2(Cl2SnOCOSnCl2)](4-) and [Pt10(CO)14{Cl2Sn(OH)SnCl2}2](2.)

The reaction of [Pt-15(CO)(30)](2-) with increasing amounts of SnCl2 affords [Pt-8(CO)(10)(SnCl2)(4)](2-) (2), [Pt-10(CO)(14){Cl2Sn(OH)SnCl2}(2)](2-) (5), [Pt-6(CO)(6)(SnCl2)(2)(SnCl3)(4)](4-) (3), [Pt-9(CO)(8)(SnCl2)(3)(SnCl3)(2)-(Cl2SnOCOSnCl2)](4-) (4) and [Pt-5(CO)(5){Cl2Sn(OR)SnCl2}(3)](3-) (R = H, Me, Et, and Pr-i) (1-R). 1-R and 2 have been previously described, whereas 3-5 are herein reported for the first time. The species 1-3 are the main products of the reaction under different experimental conditions, whereas 4 and 5 are by-products of the synthesis of 3 and 2, respectively. From a structural point of view, the clusters 1-5 all show a perfect segregation of the two metals, which are composed of a low valent Pt core decorated on the surface by Sn(II) fragments such as SnCl2, [SnCl3](-), [Cl2Sn(OH)SnCl2](-) and [Cl2SnOCOSnCl2](2-). These fragments behave as two electron donor ligands via each Sn-atom (and also the C-atom in the case of [Cl2SnOCOSnCl2](2-)). The [Cl2SnOCOSnCl2](2-) ligand is rather unique and may be viewed as a bis-stannyl-carboxylate, a carbon dioxide mu(3):k(3)-C, O, O'-CO2 or a carbonite ion [CO2](2-) stabilized by coordination to metal atoms. Compounds 1-5 have been fully characterised via IR spectroscopy, X-ray crystallography and DFT calculations.