Self-Assembly of Fourteen Components into a Soluble, Neutral, Metalloprismatic Cage

A novel one-pot synthesis of rhenium-based triangular prismatic cages has been accomplished in excellent yields by a self-assembly strategy. Reaction of Re2(CO)10 with 2,4,6-tri-4-pyridyl-1,3,5-triazine (tpt) in the presence of an aliphatic alcohol (1-butanol, 1-octanol or 1-dodecanol) afforded molecular prisms, [{(CO)3Re(μ2-OR)2Re(CO)3}3(μ3-tpt)2] (1, R = C4H9; 2, R = C8H17; 3, R = C12H25) by solvothermal methods. Fine tuning of the solubility is achieved by tailoring the length of the alkyl chain of the alcohol. Compounds 1−3 reported here are the first Re-containing molecular prisms of the M6L2L′6 type. In addition, they are the first neutral, prismatic cages without counterions that are highly air and moisture stable. Compounds 2 and 3 are soluble in most common organic solvents and they exhibit a large solvatochromism: the value of λmaxab could be tuned over 125 nm simply by changing the polarity of the solvent.