In the presence of catalytic amounts of [Pt(-P 2 O 5 H 2 ) 4 ] 4

In the presence of catalytic amounts of [Pt(μ-P₂O₅H₂)₄]⁴⁻(21) and light, 2-propanol produces H₂ and acetone (E.L. Harley, A.E. Stiegman, A. Vlcek, Jr, and H.B. Gray, J. Am. Chem. Soc., 1987, 109, 5233; D.C. Smith and H.B. Gray, Coord. Chem. Rev., 1990, 100, 169). 

(a) Give the equation for the overall reaction.

(b) Give a plausible molecular orbital scheme for the metal–metal bonding in this tetragonal-prismatic complex and indicate the nature of the excited state that is thought to be responsible for the photochemistry. 

(c) Indicate the metal complex intermediates and the evidence for their existence.