2,6-Dipicolinoylbis(N,N-dialkylthioureas) as versatile building blocks for oligo- and polynuclear architectures

Abstract

Similar reactions of 2,6-dipicolinoylbis(N,N-diethylthiourea) (H2L(a)) with: (i) Ni(NO3)2·6H2O, (ii) a mixture of Ni(NO3)2·6H2O and AgNO3, (iii) a mixture of Ni(OAc)2·4H2O and PrCl3·7H2O and (iv) a mixture of Ni(OAc)2·4H2O and BaCl2·2H2O give the binuclear complex [Ni2(L(a))2(MeOH)(H2O)], the polymeric compound [NiAg2(L(a))2]∞, and the heterobimetallic complexes [Ni2Pr(L(a))2(OAc)3] and [Ni2Ba(L(a))3], respectively. The obtained assemblies can be used for the build up of supramolecular polymers by means of weak and medium intermolecular interactions. Two prototype examples of such compounds, which are derived from the trinuclear complexes of the types [MLn(III)(L)2(OAc)3] and [MBa(L)3], are described with the compounds {[CuDy(III)(L(a))2(p-O2C-C6H4-CO2)(MeOH)4]Cl}∞ and [MnBa(MeOH)(L(b))3]∞, H2L(b) = 2,6-dipicolinoylbis(N,N-morpholinoylthiourea).

AgI Metallacoronates and HgII Metallacryptates Derived from a Catechol‐Based Aroylbis(N,N‐diethylthiourea)

“…Indeed, a number of heterometallic host–guest complexes with the ligand H 2 L py have been reported and it is evident that their composition and assembly can be controlled by fundamental concepts of inorganic chemistry such as Pearson's concept of “hard” and “soft” acids and bases . For example, a polymeric structure with helical chains results from the reaction of Ag + ions with the ligand H 2 L py in the presence of Ni 2+ ions . Very recently, first reactions of H 2 L meta , H 2 L py , and H 2 L cat with Fe 3+ and M + ions (M = Na + , K + , Rb + , Cs + , and Tl + ) have been reported and it could be shown that template effects have a strong influence on the structures of the resulting products …”

CuI/CuII Complexes with Dipicolinoylbis(N,N‐diethylthiourea): Structures, Magnetism, and Guest Ion Exchange

“…Solvents were dried and used freshly distilled unless otherwise stated. The ligand H 2 L was synthesized by the procedure reported recently ,…”

“…The coordination chemistry of 2,6‐dipicolinoylbis( N , N ‐dialkylthioureas) with transition metals was pioneered by the research of L. Beyer et al in which a polymeric Ag(I) complex of 2,6‐dipicolinoylbis( N , N ‐diethylthiourea) ( H 2 L ) was reported . Although these ligands were expected to be versatile chelating systems, there has been only another homonuclear transition metal complex of H 2 L , the binuclear nickel(II) complex, hitherto known . This interesting fact could be rationalized by the competitive reactions at two coordination sites of H 2 L namely acylthiourea and 2,6‐pyridinedicarboxamide (Scheme ) , .…”

“…Although these ligands were expected to be versatile chelating systems, there has been only another homonuclear transition metal complex of H 2 L , the binuclear nickel(II) complex, hitherto known . This interesting fact could be rationalized by the competitive reactions at two coordination sites of H 2 L namely acylthiourea and 2,6‐pyridinedicarboxamide (Scheme ) , . To get better control for the reactions of H 2 L , two different metal ions, each of which is favorably stabilized by a particular coordination site, need to be provided.…”

“…To get better control for the reactions of H 2 L , two different metal ions, each of which is favorably stabilized by a particular coordination site, need to be provided. This has been demonstrated by the self‐assembly of H 2 L with mixtures of two metal ions, such as Ni 2+ and Ln 3+ , Fe 3+ and alkali metal ions, which enable the construction of a variety of novel heterometallic complexes. Structures of such compounds are topologically analogous with those of host–guest systems like coronates and cryptates .…”