A study of MXBR3 (M = Pt, Pd or Rh; X = Cl or I) interactions in square planar ambiphilic ligand complexes: structural, spectroscopic, electrochemical and computational comparisons with borane-free analoguesElectronic supplementary information (ESI) available: Calculated structures for 1B5B, 1H5H, TXPB and [TXPBI], and X-Ray crystallographic data. CCDC 849792849797. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c2dt11991a

Reaction of [PtCl 2 (COD)] and [PtI 2 (COD)] with 2,7-di- tert -butyl-5-diphenylboryl-4-diphenylphosphino-9,9-dimethylthioxanthene (TXPB) afforded square planar [PtCl 2 (TXPB)] ( 1B ) and [PtI 2 (TXPB)] ( 4B ), both of which were crystallographically characterized. Single-crystal X-ray quality crystals were also obtained for [PdCl 2 (TXPB)] ( 2B ; Emslie et al. , Organometallics , 2008, 27 , 5317) as 2B 2CH 2 Cl 2 and solvent-free 2B . Both the chloro and iodo TXPB complexes exhibit metalhalideborane bridging interactions similar to those in previously reported [RhCl(CO)(TXPB)] ( 3B ) and [RhI(CO)(TXPB)] ( 5B ) (Emslie et al. , Organometallics , 2006, 25 , 583 and Inorg. Chem. , 2010, 49 , 4060). To facilitate a more detailed analysis of MXBR 3 (X = Cl and I) interactions, a borane-free analogue of the TXPB ligand, 2,7-di- tert -butyl-4-diphenylphosphino-9,9-dimethylthioxanthene (TXPH), was prepared. Reaction with [PtX 2 (COD)] (X = Cl or I), [PdCl 2 (COD)] and 0.5 [{RhCl(CO) 2 } 2 ] provided square planar [PtCl 2 (TXPH)] ( 1H ), [PdCl 2 (TXPH)] ( 2H ), [RhCl(CO)(TXPH)] ( 3H ) and [PtI 2 (TXPH)] ( 4H ). MClBR 3 and MIBR 3 bonding in 1B5B was then probed through the use of structural comparisons, IR and NMR spectroscopy, cyclic voltammetry, and DFT calculations (Slater-type orbitals, Mayer bond orders, Hirshfeld charges, fragment analysis, SCF deformation density isosurfaces, and energy decomposition analysis). Chloro and iodo d 8 -metal complexes of a 5-(diphenylboryl)-4-(diphenylphosphino)thioxanthene ligand (TXPB) and a borane-free analogue (TXPH) have been prepared and studied.