The interactions of CO, CO 2 , OCS, SO 2 , NO, NO 2 , N 2 O, NH 3 , PH 3 , and other small molecules with the undercoordinated metal centers of the HKUST-1 metal organic framework are studied by means of density functional theory. These molecules are potentially harmful for humans and the environment and are widely studied because of their spectroscopic properties. In this work, the energetic and vibrational characteristics of the adsorbed species are calculated. Adsorption energies on the Cu 2+ sites of the paddlewheel have been calculated, and the order is:The results show that the interactions can be classified into three categories: (1) weak physisorption, (2) polarization and electrostatics, and (3) strong acid−base. Moreover, interesting vibrational properties are calculated especially for carbonyl sulfide and dinitrogen monoxide, which can be bound via two different configurations on the metal atoms. The vibrational modes are shifting in different directions depending on the binding way of the molecule; e.g., the symmetric stretching of OCS is shifted by +17 or −16 cm −1 when bound via the oxygen or the sulfur atom, respectively.

Dedicated to the 60 th birthday of Prof. Thomas FrauenheimReceived ZZZ, revised ZZZ, accepted ZZZ Published online ZZZ (Dates will be provided by the publisher.)

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The TNU-9 zeolite (TUN framework) is one of the most complex zeolites known. It represents a highly promising matrix for both acid and redox catalytic reactions. We present here a newly developed approach involving the use of Si and Al (3Q) MAS NMR spectroscopy, Co as probes monitored by UV/Vis and FTIR spectroscopy, and extensive periodic DFT calculations, including molecular dynamics, to investigating the aluminum distribution in the TUN framework and the location of aluminum pairs and divalent cations in extra-framework cationic positions. Our study reveals that 40 and 60 % of aluminum atoms in the TNU-9 zeolite are isolated single aluminum atoms and aluminum pairs, respectively. The aluminum pairs are present in two types of six-membered rings forming the corresponding α and β (15 and 85 %, respectively, of aluminum pairs) sites of bare divalent cations. The α site is located on the TUN straight channel wall and it connects two channel intersections. The suggested near-planar β site is present at the channel intersection.

Metal–organic frameworks (MOFs) provide new possibilities for their potential use in catalysis, gas storage/separation, and drug delivery. In this work, a computational study is performed on the interaction of biologically important organic molecules such as caffeine, urea, niacin, and glycine with the undercoordinated copper centers of the HKUST-1 MOF. Density functional theory calculations are used to identify the adsorption sites of the organic molecules in HKUST-1 and to calculate their interaction energies. Two types of interactions are calculated: (i) strong binding via their nitrogen or oxygen atoms with the copper atoms of the paddlewheel and (ii) hydrogen bonds with the carboxylate groups of the MOF. Certain molecules such as caffeine and niacin can interact simultaneously with more than two paddlewheels, thus making the interactions even stronger. The interaction energies vary from 75 kJ mol–1 for glycine to 200 kJ mol–1 for caffeine. The confinement of the guest molecules in the cage windows of the framework can also create strong interactions. To take into account the effect of coordination with multiple paddlewheels, a very large model of the HKUST-1 needs to be used. The numbers of (i) copper sites interacting with the guest molecule and (ii) hydrogen bonds between the carboxylate groups of the MOF and the guests have a major impact on binding strength. This is important information when applying rational design to create new MOFs that should serve as drug carriers.