The structures of the fully exchanged, fully dehydrated zeolites Tl-ZSM-5 (a ) 20.064(1), b ) 19.946(1), c ) 13.416(1) Å) and H-ZSM-5 (a ) 20.079(1), b ) 19.948(1), c ) 13.419(1) Å) have been determined crystallographically using modestly twinned single crystals and synchrotron X-radiation. They were refined in the orthorhombic space group Pnma to R 1 ) 0.071 and 0.066 with 3962 and 4278 reflections, respectively, for which F o > 4σ(F o ). The geometry of the zeolite framework in both crystals (MFI, Al 3.2 Si 92.8 O 192 , Si/Al ) 29) is very similar to that in earlier determinations. The ZSM-5 framework and Tl + positions are described using the four nonequivalent partially overlapping 10-rings (R), the two channel systems (C), the channel intersection volume, and the cove of the ZC. The latter two comprise the conventionally defined cavity. The zigzag (sinusoidal) channel (ZC) passes through R1, R3, and R4; the straight channel (SC) passes through R2. A total of 3.3(2) Tl + ions per unit cell were found scattered among 18 crystallographically distinct positions. Based on their positions near R1, R2, and R3, these positions may be classified into three groups (Gn, n ) 1-3), each with two general cation sites (Sn and Sn′). Of the 18 Tl + positions, six are in the intersection volume (at S2′ in G2), 11 are elsewhere in the ZC (in G1 and G3), and one is elsewhere in the SC (at S2) just outside the intersection volume. Among the six general cation sites, S1′ at the mouth of the cove has the highest Tl + population, 28% of the total. Of the 18 Tl + positions, 14 bond strongly to framework oxygen atoms with 2.68(4) < Tl-O < 2.87(5) Å (Tl + + O 2radii ) 2.79 Å); three other shortest distances range upward to 2.97(5) Å; one at 3.18(10) Å appears to be an unresolved position. The framework sites (T) that Al atoms preferentially occupy are identified from Tl + occupancies and Tl-O bond distances. Using Tl-O < 2.70 Å, the order is T10 (most preferred) > T6. The preference of Al for the T10 site remains when longer, less reliable but more comprehensive, Tl-O bond length criteria are used. Using Tl-O < 2.80 Å, the order is T10 > T6 ∼ T9 > T5 > T4 > T2 > T12 > T7 > T11, and with Tl-O < 2.90 Å, the preference order includes all 12 T sites: T10 > T3 > T2 > T12 > T6 ∼ T9 > T5 > T4 > T8 > T7 > T11 > T1. T10 is a member of R4, the 10-ring that is common to the intersection volume and the cove.

The face-driven corner-linked truncated octahedral nanocages, [Pd6L8]12+ (1, L1 = N,N',N' '-tris(3-pyridinyl)-1,3,5-benzenetricarboxamide; 2, L2 = N,N',N' '-tris(4-pyridinylmethyl)-1,3,5-benzenetricarboxamide), were prepared with eight C3-symmetric tridentate ligands and six square planar tetratopic palladium(II) ions. The combination of the nitrogen donor atom at a approximately 120 degrees kink position of the carboxamido pyridinyl group and the tilted pyridyl versus the facial plane of the ligands can provide the needed curvature for the formation of octahedral cages. The nitrogen atoms can coordinate to the square planar palladium(II) ions to form kinks with approximately 120 degrees angles at the C4-symmetric square planar corners of the truncated octahedron. Depending on the conformation of the ligand, L1, two different truncated octahedral cages of around 2.4 nm in diameters were formed. The major form of 1 with syn-conformational ligands has a cavity volume of approximately 1600 A3. The cage has 12 ports (3.4 x 3.5 A2) at all edges of the octahedron. The minor form of cage 1 with anti-conformational ligands has a slightly increased cavity volume ( approximately 1900 A3) and port size (3.3 x 8.0 A2). The insertion of a methylene group in L2 has not only increased the cavity volume of 2 to approximately 2200 A3 but also enlarged the port size to 4.1 x 8.0 A2. However, an atomic force microscopy (AFM) study of cage 2 showed that the cages had a height of 1.8 +/- 0.1 nm. This value is about 30% smaller than the calculated size of 2.6 nm from the crystal structure. This tip-induced decrease in height in cage 2 suggests the nonrigidity of cage 2.

A novel S4-symmetric icosanuclear manganese metalladiazamacrocycle was synthesized using a pentadentate ligand, N-3-phenyl-trans-2-propenoylsalicylhydrazide (H3L), that has a rigid and bulky terminal N-acyl group. A 20 cyclic repeat of an--(Mn-N-N)--linkage resulted in a highly puckered diaza-bridged 60-membered icosanuclear metallamacrocycle. The steric interaction between the ligands in the cyclic system leads to five consecutive Mn(III) centers in a chemically different--(Mn(A)Mn(B)Mn(C)Mn(D)Mn(E))--environment, with the chiralities of the metal centers being in a rather complicated--(LambdaLambdaDeltaLambdaLambda)(DeltaDeltaLambdaDeltaDelta)--sequence.