A porphyrin complex of gold(I): (phosphine)gold(I) azides as cation precursors.

A silver- and Brönsted acid-free protocol for generating the (tricyclohexylphosphine)gold(I) cation from the corresponding azide complexes is disclosed. The gold(I) cations so liberated are trapped by complexation with octaethylporphyrin. The first structurally authenticated gold(I) porphyrin complex crystallizes with formula C(72)H(112)Au(2)F(12)N(4)P(2)Sb(2), space group C2/c, a = 21.388 (4), b = 19.679 (4), c = 19.231 (3) A; beta = 111.030 (3) degrees. Solution spectroscopic studies indicate that the di-gold complex fragments on dissolution in organic solvents. Approximate density-functional theory calculations find an electrostatic origin for the binding of two gold(I) centers to the unprotonated nitrogen atoms, despite greater orbital density on the porphyrin meso carbons.