Davide M. Proserpio

Polycatenation, polythreading and polyknotting in coordination network chemistry

The use of crystal engineering concepts has produced a variety of coordination networks, many of which exhibit novel and fascinating types of entanglements of individual motifs. This review analyses the structures of a number of entangled polymeric networks reported in these years by many groups. A topological classification of the different interlocked and interweaved species is attempted. Wide classes of polycatenated and polythreaded species have been recognized and other phenomena, as polyknotting (self-penetration) and interweaving of 1D chains, are also discussed. Unexpected topological features and new linkages, that were previously overviewed, have been discovered, including the first examples of infinite Borromean links.

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.

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.

Borromean links and other non-conventional links in ‘polycatenated’ coordination polymers: re-examination of some puzzling networks

A number of coordination networks, exhibiting novel and fascinating types of entanglements of individual motifs have been reported throughout the years by many groups. The structural complexity of these species has caused, in some cases, misinterpretations regarding the correct nature of the entanglement. In this article, we analyse the structures of some polymeric networks of the ‘polycatenanes’ class, which have the peculiar feature of all the constituent motifs having lower dimensionality than that of the overall array. Unexpected topological features and new linkages, that had previously been overlooked, have been discovered. The most relevant finding concerns the first observation of examples of Borromean links in 3D and 2D arrays. These systems are comprised of layers that are not catenated but, nonetheless, inseparably entangled in an uncommon topological fashion.

Complex Interwoven Polymeric Frames from the Self‐Assembly of Silver(I) Cations and Sebaconitrile

Interwoven networks have been isolated from the self-assembly of the flexible long-chain sebaconitrile (1,10-decanedinitrile) and different silver(I) salts. These networks include an eightfold interpenetrated diamondoid frame (I), a fourfold interwoven 3D four-connected frame topologically related to the prototypical SrAl2 (II), an infinitely catenated 2D multilayer (III), and a 3D entangled array (IV).

A new type of entanglement involving one-dimensional ribbons of rings catenated to a three-dimensional network in the nanoporous structure of [Co(bix)2(H2O)2](SO4)·7H2O [bix = 1,4-bis(imidazol-1-ylmethyl)benzene]

Co(II) sulfate reacts with the flexible ligand 1,4-bis(imidazol-1-ylmethyl)benzene (bix) to yield the coordination network [Co(bix)2(H2O)2](SO4).7H2O, containing polymeric ribbons of rings which penetrate and catenate a 3D single frame of the CdSO4 topology, to produce an open-channel entangled architecture with nanoporous behaviour.

New polymeric networks from the self-assembly of silver(I) salts and the flexible ligand 1,3-bis(4-pyridyl)propane (bpp). A systematic investigation of the effects of the counterions and a survey of the coordination polymers based on bpp

The self-assembly of polymeric networks from different Ag(I) salts and the flexible ligand 1,3-bis(4-pyridyl)propane (bpp) has been systematically investigated in order to obtain some basic information useful for the crystal engineering of coordination frames upon variation of the counterions. The salts AgNO3, AgBF4, AgClO4, AgPF6, AgAsF6 and AgSbF6 have been reacted in the molar ratio Ag∶bpp of 1∶2. Though in some cases we have observed the formation of mixtures, containing also minor amounts of the 1∶1 adducts [Ag(bpp)]X, the [Ag(bpp)2]X derivatives have been obtained for all the salts, and all of the isolated crystalline products have been characterized by single-crystal X-ray analysis. Polymeric 2D and 3D networks have been observed, exhibiting four different structural motifs: [Ag(bpp)2](NO3) (1) contains 2D layers of square meshes that show 2-fold parallel interpenetration; compounds [Ag(bpp)2](BF4) (2) and [Ag(bpp)2](ClO4) (3) are isomorphous and contain 2-fold interpenetrated diamondoid networks; more surprisingly, compounds [Ag(bpp)2](PF6) (4) and [Ag(bpp)2](AsF6) (5) show a wafer-like structure containing, for the first time, 2-fold entangled (4,4) layers alternated to simple (4,4) layers; and finally, [Ag(bpp)2](SbF6) (6) contains single 2D layers of tessellated 4-membered rings. A brief analysis of the known coordination polymers based on the bpp ligand is also reported, including the structure of the novel species [Cu(NO3)2(bpp)]2·2CH2Cl2, a molecular ring that represents the unique example showing the GG conformation for the bpp ligands.

Low temperature route towards new materials: solvothermal synthesis of metal chalcogenides in ethylenediamine

Abstract Solid state reactions occur among solid reactants and are characterized by slow nucleation and diffusion processes. Thus, high temperature is often required to promote the reactions to proceed at an appropriate rate. Kinetic control and mechanistic study of these systems are usually very difficult. One has little control in rational design and prediction of the structures coming out of the reactions. High temperature products are often limited to the thermodynamically most stable phases. The recent development in soft synthesis of metal chalcogenides has been motivated and stimulated by the tremendous progress in the crystal engineering of organic and coordination compounds via molecular building-block approaches. The hope is that by turning down the temperature, the solid state synthesis may proceed in a more controlled and predictable manner. Much research has been carried out in exploration and investigation of various soft synthetic techniques. In this article, we will focus only on the recent development in solvothermal synthesis using ethylenediamine as a reaction medium.

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