The building block approach to extended solids: 3,5-pyrazoledicarboxylate coordination compounds of increasing dimensionality

Abstract

A series of M(II) complexes with the ligand 3,5-pyrazoledicarboxylic acid (H3dcp) has been synthesised mainly via hydrothermal reactions and their structures have been characterised. Simple mononuclear [Ni(Hdcp)(H2O)4] (1), Na2(mu-H2O)2(H2O)8[Ni(Hdcp)2(H2O)2] (2), [M(H2dcp)2(H2O)2] x 2H2O [M = Co (3), Zn (4) and Cu (5)] and dinuclear (Et3NH)2[Cu2(dcp)2(H2O)2] (9) building blocks have been isolated and subsequently linked into 1-D chains [Mn(Hdcp)(H2O)2]infinity (6), [[Mn(H2O)4][Mn(Hdcp)2(H2O)2] x 4H2O]infinity (7), [Ni2(Hdcp)2(mu-H2O)2(H2O)2]infinity (8), [[Ni(H2O)4][Ni2(dcp)2(H2O)4]]infinity (11), or 3-D arrays [[Na2(mu-H2O)2][Cu2(dcp)2]]infinity (10), [Cu3(dcp)2(H2O)4]infinity (12), utilising novel bridging modes of the H3dcp ligand. In the unprecedented 1-D Ni(II) chain 8, rarely reported double aqua-bridges link the Ni(II) ions to form an inter-linked double stranded chain. The magnetic properties of these compounds have been measured and reveal a variety of antiferromagnetic coupling behaviours induced by the ligand bridging modes.

A New Basic Motif in Cyanometallate Coordination Polymers: Structure and Magnetic Behavior of M(μ‐OH2)2[Au(CN)2]2(M=Cu, Ni)

“…Relative to the large number of oxoand hydroxo-bridged metal centers, only a small number of aqua-bridged copper(II) and nickel(II) dimers are known. [36][37][38] If the water is thermally removed, 1 and 2 undergo a significant structural rearrangement to reoccupy some of the vacated metal-coordination sites. The diffractogram of 1 a shows a small number of broad peaks ( Figure S3) that are shifted relative to that observed for 1.…”

“…Similar to 1, these ferromagnetic interactions are probably mediated through the NiA C H T U N G T R E N N U N G (m-OH 2 ) 2 Ni bridge (J 1 ). Very few aqua-bridged nickel-A C H T U N G T R E N N U N G (II) dimers or chains have been reported, [38,55] and of these, the magnetic properties were rarely investigated. Antiferromagnetic interactions were observed in the double-stranded [38] The double aqua-bridge was determined to be the dominant magnetic pathway in this system, yielding a J value of À1.6(2) cm…”

Anisotropic Movements of Coordination Polymers upon Desolvation: Solid‐State Transformation of a Linear 1D Coordination Polymer to a Ladderlike Structure

“…The hydrogen atoms of the coordinated water molecules from two neighboring polymeric strands bridge the oxygen atoms of two non-coordinated trifluoroacetate ions through hydrogen bonds (OÀH···O, d = 1.87 , D = 2.74 , q = 1628) to form a 12-membered ring [notation R 4 4 (12)], [11] similar to the analogous interactions reported in the literature. [12] This connectivity leads to hydrogen-bonded, 2D brickwall-like structures approximately in the ac plane, as a result of the anti dispositions of the AgÀO bonds in the polymer chains caused by crystallographic inversion at the double bonds. The closest Ag···Ag distances in this plane are 9.43 and 10.43 .…”

Dimensionality Variation in Dinuclear Cu(II) Complexes of a Heterotritopic Pyrazolate Ligand

“…Substitution at the 3-and/or 5-positions of the pyrazole ring gives rise to a series of compounds capable of chelating two adjacent metal ions, to form discrete clusters or polymeric architectures, such as the well-studied 3,5-dicarboxy-1H-pyrazole and 3,5-di(2-pyridyl)-1H-pyrazole ligands [25,26]. Despite the popularity of symmetric 3,5-disubstituted pyrazole ligands, there are few examples of unsymmetrical 3,5-disubstituted pyrazole ligands.…”