Eleven- and twelve-vertex polyhedral metalladithiaborane chemistry. Novel compounds from the arachno-[S 2 B 9 H 10 ] – anion: [(PPh 3 ) 3 H 2 IrS 2 B 9 H 10 ], [(PPh 3 ) 2 HIrS 2 B 9 H 9 ] and [(PPh 3 ) 2 HRhS 2 B 8 H 8 ]

Reaction of the arachno-[S2B9H10]– anion with [IrCl(PPh3)3] yields (a)[(PPh3)3H2IrS2B9H10], in which cluster–metal interaction occurs solely via heteroatom η1 two-electron, two-centre, cluster-to-metal donation, and (b)[(PPh3)2HlrS2B9H9], which has a contiguous nido-type twelve-vertex cluster structure with η5 cluster-to-metal donation, whereas reaction with [RhCl(PPh3)3] results in one-atom cluster dismantlings to give nido-type eleven-vertex (c)[(PPh3)2HRhS2B8H8] and (d)[(PPh3)2RhSB9H10], both with η4 cluster-to-metal donation.