V. A. Blatov

Interpenetrating metal–organic and inorganic 3D networks: a computer-aided systematic investigation. Part I. Analysis of the Cambridge structural database

The occurrence of interpenetration in metal–organic and inorganic networks has been investigated by a systematic analysis of the CSD and ICSD structural databases. For this purpose, a novel version of TOPOS (a program package for multipurpose crystallochemical analysis) has been employed, where the procedure of recognition of interpenetrating nets is based on the representation of a crystal structure as a finite reduced graph. In this paper we report a comprehensive list (301 Refcodes) of interpenetrating metal–organic 3D structures from CSD, that are analyzed on the basis of their topologies. Interesting trends and novel features have been observed and distinct classes of interpenetrating nets have been envisaged, depending on the relationships of the individual motifs.

TOPOS3.2: a new version of the program package for multipurpose crystal-chemical analysis

The principal features of the package are as follows. (i) Management of crystal structure information with DBMS (database management system) which has gateways to the CSD and ICSD databases. (ii) Comprehensive analysis of geometrical and topological properties of crystal structures (employing the programs Dirichlet, AutoCN, ADS, DiAn, IsoCryst and IsoTest). (iii) Special facilities for statistical analysis of large sets of crystal structures (the program StatPack). In addition to the programs contained in the previous version (Blatov et al., 1999), version 3.2 includes the following two programs. (a) IsoTest, which provides an automatic search for the topological similarity (isotypism) in large groups of stoichiometrically and structurally different compounds, on three levels: the whole topological and geometrical similarity (crystal-chemical isotypism; Lima-deFaria et al., 1990); only the whole or partial topological similarity of crystal structures (topological isotypism; Blatov, 2000); topological similarity of separate atomic subnets and packings. (b) HSite, which searches for hydrogen positions in crystal structures of organic, organometallic and inorganic compounds. Besides traditional methods of geometrical and statistical analysis, and graphical representation of crystal structures (the programs DiAn, IsoCryst and StatPack), there are two novel concepts used in TOPOS algorithms: the concept of an atomic domain represented as a Voronoi±Dirichlet polyhedron (the program Dirichlet; Blatov et al., 1995) and the concept of a periodic net described as a contracted graph (the programs ADS, AutoCN and IsoTest; Blatov, 2000). The program IsoTest automatically enumerates all variants of topological representation of crystal structures and ®nds similar ones through a given list of compounds by comparing coordination sequences (Brunner & Laves, 1971) of corresponding atomic subnets (Blatov, 2000). The program HSite uses characteristics of Voronoi±Dirichlet polyhedra to predict the optimal positions of hydrogen atoms and orientation of atomic groups.

Vertex-, face-, point-, Schläfli-, and Delaney-symbols in nets, polyhedra and tilings: recommended terminology

We review the various kinds of symbols used to characterize the topology of vertices in 3-periodic nets, tiles and polyhedra, and symbols for tilings, making a recommendation for uniform nomenclature where there is some confusion and misapplication of terminology.

Underlying nets in three-periodic coordination polymers: topology, taxonomy and prediction from a computer-aided analysis of the Cambridge Structural Database

We discuss a recently developed approach to formalize the analysis of extended architectures by successive simplifications of a crystal structure perceived as a periodic net. The approach has been implemented into the program package TOPOS that allows one to simplify and classify coordination polymers of any complexity in an automated mode. Using TOPOS, we retrieved 6620 3-periodic coordination polymers from the Cambridge Structural Database and represented them in a standard way as underlying nets. The topological classification of both 975 interpenetrating and 5645 single 3-periodic underlying nets has been performed and compared. The up-to-date methods for prediction of the topology of underlying nets are discussed and the ways to develop reticular chemistry are outlined.

Nanocluster analysis of intermetallic structures with the program package TOPOS

General principles of the analysis of intermetallic compounds with the program package TOPOS are considered. The nanocluster method is described in detail, which lies in the base of the TOPOS “Nanoclustering” procedure. The applications of the nanocluster method to intermetallic compounds as well as to porous materials are comprehensively overviewed. The perspectives of extending the nanocluster model to other classes of inorganic compounds are outlined.

Two metal–organic frameworks with unique high-connected binodal network topologies: synthesis, structures, and catalytic properties

{[Cd3(btec)(btx)0.5(μ3-OH)(H2O)]·H2O}n (1) and [Cu2(btec)(btx)1.5]n (2), two novel cadmium(II) and copper(II)-based high-connected metal–organic frameworks, with both 1,2,4,5-benzenetetracarboxylate (btec) and 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene (btx) as mixed ligands were hydrothermally synthesized and structurally characterized. Both MOFs have three-dimensional (3D) structures, but different framework topologies and ligand linkage modes. 1 possesses an unprecedented binodal (4,12)-connected topology structure, in which the ligand btec serves as a rare dodecadentate and ordinary octadentate in two types of coordination modes. Meanwhile, 2 exhibits a binodal (4,7)-connected topological network with an enneadentate coordination geometry of the btec ligand. Both MOFs provide novel examples of designing and synthesizing novel binodal MOFs, and demonstrate that the 1,2,4,5-benzenetetracarboxylic acid ligand with rich coordination chemistry information is useful in the construction of binodal highly-connected nets. In addition, the catalytic performance of 2 has also been checked. 2 is active as a catalyst for the degradation of methyl orange.

Entangled Two-Dimensional Coordination Networks: A General Survey

Survey Lucia Carlucci,*,† Gianfranco Ciani,† Davide M. Proserpio,*,†,‡ Tatiana G. Mitina,‡ and Vladislav A. Blatov*,‡,§ †Dipartimento di Chimica, Universita ̀ degli Studi di Milano, Via C. Golgi 19, 20133 Milano, Italy ‡Samara Center for Theoretical Materials Science, Samara State University, Ac. Pavlov Street 1, Samara 443011, Russia Chemistry Department, Faculty of Science, King Abdulaziz University, Post Office Box 80203, Jeddah 21589, Saudi Arabia

Topological relations between three-periodic nets. II. Binodal nets.

The TOPOS program package was used to generate all subnets of 3- to 12-coordinated binodal nets taken from the Reticular Chemistry Structure Resource database. 38,304 binodal nets with novel topologies were revealed and stored in the TTD collection. A new invariant, the adjacency matrix of the shell graph of a node, is proposed to distinguish the node local topology. With this invariant, the first six examples of binodal-quasi-uninodal nets were discovered. 4604 organic and metal-organic frameworks were analyzed to find examples of the topologies generated. It was shown that many edge-transitive nets as well as unknown topologies occur in crystal structures.

Interpenetrated three-dimensional hydrogen-bonded networks from metal–organic molecular and one- or two-dimensional polymeric motifs

The occurrence of interpenetrated three-dimensional networks has been systematically investigated by the analysis of the crystallographic structural databases, using the program package TOPOS. After our previous reports on interpenetration observed in valence-bonded MOFs, inorganic arrays and hydrogen-bonded organic supramolecular architectures, in this paper we have focused our research on the interpenetrated 3D networks based on hydrogen-bonded metal–organic molecular (0D) and polymeric (1D and 2D) complexes from the Cambridge Structural Database. The current interest for the crystal engineering of new functional materials has prompted many research groups to adopt synthetic strategies implying the use of molecular metal complexes (0D) with suitably exo-oriented hydrogen-bond donor and acceptor groups for the assembly of extended networks. With regard to this we have examined 3D hydrogen-bonded supramolecular arrays formed by finite and infinite motifs of lower dimensionality, analyzing their topologies and looking for their entanglements. We have extracted a comprehensive list including 135 different motifs (71 assembled from 0D, 43 from 1D and 21 from 2D metal–organic motifs) showing the phenomenon of interpenetration (about two thirds not detected in the original papers). These hydrogen-bonded networks include species assembled by one or more building blocks, that are classified within the previously introduced Classes of interpenetration. It is observed that the maximum interpenetration degree is limited to 5-fold and the main (overall) topology is 412.63-pcu. An analysis of the possible relationships between the dimensionality of the building blocks and the resulting network connectivity and topology, and of some factors determining the interpenetration is also attempted, together with a comparison of the present results with those for other families of interpenetrated materials.

Three-periodic nets and tilings: natural tilings for nets

Rules for determining a unique natural tiling that carries a given three-periodic net as its 1-skeleton are presented and justified. A computer implementation of the rules and their application to tilings for zeolite nets and for the nets of the RCSR database are described.