Reaction of the microporous metal-organic framework Zn
4O(BDC)
3 (BDC
2- = 1,4-benzenedicarboxylate) with Cr(CO)
6 at 140 <
IMG SRC="/images/entities/deg.gif">C in a 6:1 mixture of dibutylether and THF affords Zn
4O[(BDC)Cr(CO)
3]
3 (
1). This compound retains the porous cubic structure of the parent framework, but features Cr(CO)
3 groups attached in an
6 fashion to all of the benzene rings. Compound
1 is also microporous, exhibiting a BET surface area of 2130 m
2/g. It can be fully decarbonylated by heating at 200
C, but the resulting
gray solid (
2) shows little affinity for N
2 or H
2 at 298 K, suggesting aggregation of the chromium atoms. In contrast, photolysis of
1 using 450-nm light in an atmosphere of N
2 or H
2 produces solids with infrared spectra indicative of Zn
4O[(BDC)Cr(CO)
2(N
2)]
3 (
3) and Zn
4O[(BDC)Cr(CO)
2(H
2)]
3 (
4). Under an N
2 atmosphere, compound
4 completely converts into compound
3 over the course of 12 h, demonstrating the lability of the Cr
0-H
2 bond. Owing to isolation of the metal centers within the rigid, evacuable framework structures, the N
2- and H
2-substituted compounds show greatly enhanced stability relative to molecular analogues generated in frozen gas matrices or supercritical fluid solutions.