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.

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

Azido has been one of the well used bridging ligands in the construction of magnetic molecule materials, which has stimulated considerable interest in magnetochemistry. This tutorial review is concentrated on the study of azido metal compounds with their magnetochemistry and consists of eight main sections. The first section offers an introduction to azido complexes and some important results obtained from magneto–structural correlation in azido complexes which will be referred to in the following sections. The next six sections give overviews of azido-mediated ferromagnets, ferrimagnets, canted (weak) ferromagnets, antiferromagnets, single molecule magnets (SMMs) and single chain magnets (SCMs), and metamagnets. The last section is the conclusion and gives a perspective of azido-mediated magnets.

Azido-mediated systems showing different magnetic behaviors

Halogen bonds in the solid state have been investigated for many years, with a major resurgence in activity occurring in the past decade. The emphasis of most studies has been on organic components. This Highlight focusses on inorganic components, or at least metal-containing components, and explores their propensity to form halogen bonds. The use of C–X⋯X′–M halogen bonds in forming networks is briefly reviewed and their utility in investigating the nature of halogen bonds is explored since their strength can be tuned by changing either the organic (donor) halogen (C–X) or the inorganic (acceptor) halogen (M–X′). A survey has been performed of crystal structures in which interactions are of suitable geometry to be considered as halogen bonds. In particular the role of simple monatomic (e.g.oxo, nitrido) and diatomic (e.g.carbonyl, cyanide) ligands as halogen bond acceptors in transition metal complexes is examined. Main group metals are also considered in a further section that considers D–X⋯A–M halogen bonds, where D = halogen bond donor, A = halogen bond acceptor and M = main group metal or metalloid. Many examples presented herein were not identified as halogen bonds in the original articles. The aim of this survey is to examine the breadth of elements that can be involved in halogen bonding involving at least one inorganic (metal-containing) component and consider this range of interactions as a basis for future research in halogen bonding with applications in crystal engineering and allied areas.

Combining metals with halogen bonds

Structural and magnetic studies on copper(II) azido complexes

Two novel three-dimensional complexes formulated as [M3(bime)2(μ3-OH)2(HO−BDC)2]n (M = Co, 1; Cu, 2) [bime = 1,2-bis(imidazol-1‘-yl)ethane, HO−H2BDC = 5-hydroxyisophthalic acid] have been hydrothermally synthesized and characterized Both 1 and 2 exhibit similar structural frameworks resulting from one-dimensional metal/oxygen chains extended by HO−BDC, but the bridging modes of HO−BDC and coordination environments of metal centers are different Complexes 1 and 2 crystallize in the orthorhombic system, space group Pbcn, a = 18458(2) [182119(12) for 2] A, b = 120616(14) [116847(7)] A, c = 114859(14) [120688(6)] A, and Z = 4 (4) Magnetic studies show that 1 displays a slow magnetic relaxation, a large hysteresis, and distinct finite-size effects and 2 contains an antiferromagnetic chain

Two Three-Dimensional Metal−Organic Frameworks Containing One-Dimensional Hydroxyl/Carboxylate Mixed Bridged Metal Chains: Syntheses, Crystal Structures, and Magnetic Properties

Two novel inorganic-organic hybrid 3D extended networks of Ni(II) and Mn(II) having molecular formulas [(maleate)(2)Ni(3)(bpe)(4)(H(2)O)(4)](NO(3))(2).H(2)O (1) and [(adipate)Mn(bpe)] (2) (bpe = 1, 2-bis(4-pyridyl)ethane), respectively, have been synthesized and characterized by single-crystal X-ray diffraction studies and low-temperature (300-2 K) magnetic measurements. Compound 1 crystallizes in the monoclinic system, space group C2/c (No. 15), with chemical formula C(56)H(62)N(10)Ni(3)O(19), a = 30.955(4) A, b = 12.705(3) A, c = 17.058(5) A, beta = 117.26(2) degrees, and Z = 4. Compound 2 crystallizes in the triclinic system, space group Ponemacr; (No. 2), with chemical formula C(18)H(20)MnN(2)O(4), a = 8.492(2) A, b = 9.444(2) A, c = 11.533(3) A, alpha = 97.19(1) degrees, beta = 94.64(1) degrees, gamma = 105.02(1) degrees, and Z = 2. The structure determination reveals for both a 3D network. Compound 1 contains two crystallographically independent Ni(II) ions in different octahedral environments. Ni(1) lies on an inversion center, and its coordination environment comprises two chelating maleate anions and two bpe nitrogen donors, while the Ni(2) ion is surrounded by meridionally disposed three bpe N atoms, two water molecules, and one oxygen donor from the dicarboxylate anion. Of the three crystallographic independent bpe ligand, one presents an anti and the others a gauche conformation. The corresponding N-to-N distances are 9.344, 6.543, and 6.187 A. Variable-temperature magnetic susceptibility measurement of the complex reveals the existence of a dominant ferromagnetic interaction within the molecule. Compound 2 is composed of Mn(2) dimer units linked by adipate anions to form corrugated 2D sheets which, on interconnection through bpe (anti conformation, N-to-N distance of 9.391 A), produces an interpenetrated 3D alpha-polonium-related type net. Complex 2 reveals to be antiferromagnetic fitting data using a dimeric Mn(II) model that considers negligible magnetic transmission through the carbon skeleton of adipate and the bpe pathway.

Structural analyses and magnetic properties of 3D coordination polymeric networks of nickel(II) maleate and manganese(II) adipate with the flexible 1,2-bis(4-pyridyl)ethane ligand.

A novel 1-D chain of Cu(II) with alternate single end-on and single end-to-end azido bridge having a very high Cu−N3(1,1)−Cu bond angle (129.98°) has been synthesized and characterized, which shows an intrachain antiferromagnetic interaction (J = −11.5 cm-1 for end-on bridge and −2.7 cm-1 for end-to-end bridge).

The first structurally alternating copper(II) chain with alternate single end-on and end-to-end azido bridging: a synthesis, crystal structure, and low-temperature magnetic study.

Three new metal-organic polymeric complexes, [Fe(N(3))(2)(bpp)(2)] (1), [Fe(N(3))(2)(bpe)] (2), and [Fe(N(3))(2)(phen)] (3) [bpp = (1,3-bis(4-pyridyl)-propane), bpe = (1,2-bis(4-pyridyl)-ethane), phen = 1,10-phenanthroline], have been synthesized and characterized by single-crystal X-ray diffraction studies and low-temperature magnetic measurements in the range 300-2 K. Complexes 1 and 2 crystallize in the monoclinic system, space group C2/c, with the following cell parameters: a = 19.355(4) A, b = 7.076(2) A, c = 22.549(4) A, beta = 119.50(3) degrees, Z = 4, and a = 10.007(14) A, b = 13.789(18) A, c = 10.377(14) A, beta = 103.50(1) degrees, Z = 4, respectively. Complex 3 crystallizes in the triclinic system, space group P(-)1, with a = 7.155(12) A, b = 10.066(14) A, c = 10.508(14) A, alpha = 109.57(1) degrees, beta = 104.57(1) degrees, gamma = 105.10(1) degrees, and Z = 2. All coordination polymers exhibit octahedral Fe(II) nodes. The structural determination of 1 reveals a parallel interpenetrated structure of 2D layers of (4,4) topology, formed by Fe(II) nodes linked through bpp ligands, while mono-coordinated azide anions are pendant from the corrugated sheet. Complex 2 has a 2D arrangement constructed through 1D double end-to-end azide bridged iron(II) chains interconnected through bpe ligands. Complex 3 shows a polymeric arrangement where the metal ions are interlinked through pairs of end-on and end-to-end azide ligands exhibiting a zigzag arrangement of metals (Fe-Fe-Fe angle of 111.18 degrees) and an intermetallic separation of 3.347 A (through the EO azide) and of 5.229 A (EE azide). Variable-temperature magnetic susceptibility data suggest that there is no magnetic interaction between the metal centers in 1, whereas in 2 there is an antiferromagnetic interaction through the end-to-end azide bridge. Complex 3 shows ferro- as well as anti-ferromagnetic interactions between the metal centers generated through the alternating end-on and end-to-end azide bridges. Complex 1 has been modeled using the D parameter (considering distorted octahedral Fe(II) geometry and with any possible J value equal to zero) and complex 2 has been modeled as a one-dimensional system with classical and/or quantum spin where we have used two possible full diagonalization processes: without and with the D parameter, considering the important distortions of the Fe(II) ions. For complex 3, the alternating coupling model impedes a mathematical solution for the modeling as classical spins. With quantum spin, the modeling has been made as in 2.

Talal Mallah

Papers

Structural analyses and magnetic properties of 3D coordination polymeric networks of nickel(II) maleate and manganese(II) adipate with the flexible 1,2-bis(4-pyridyl)ethane ligand.

The first structurally alternating copper(II) chain with alternate single end-on and end-to-end azido bridging: a synthesis, crystal structure, and low-temperature magnetic study.

Syntheses, Structural Analyses, and Magneto-Structural Correlations of Three Polymeric Fe(II) Complexes with Azide Ligand