Silyl, hydrido-silylene, or other bonding modes: some unusual structures of [(dhpe)Pt(SiHR2)]+ (dhpe = H2P-CH2-CH2-PH2; R = H, Me, SiH3, Cl, OMe, NMe2) and [(dhpe)Pt(SiR3)](+) (R = Me, Cl) from DFT calculations.