Silver(I) pyrophosphonates: structural, photoluminescent and thermal expansion studies.

The solvothermal reactions of silver(I) salts with mono-organophosphonic acids, i.e. 3-thienylphosphonic acid (3-TPA), phenylphosphonic acid (PPA), α-naphthylphosphonic acid (α-NPA) and cyclohexylphosphonic acid (CPA), yield four new silver(I) pyrophosphonates, namely: [Ag(2)(ptp)] (1), [Ag(2)(ppp)] (2), [Ag(3)(CH(3)CN)(pnp)(pnpH)] (3), and [Ag(3)(pcp)(pcpH)] (4) [ptp(2-) = pyro-3-thienylphosphonate, ppp(2-) = pyrophenylphosphonate, pnp(2-) = pyro-α-naphthylphosphonate, pcp(2-) = pyrocyclohexylphosphoante]. In all cases, the pyrophosphonate ligands are generated in situ from their relative mono-organophosphonic acids, mediated by silver(I) ions. Single crystal structural determinations reveal that compounds 1 and 2 display two-dimensional layer architectures, while 3 and 4 show one-dimensional chain structures. Structure 1 can be best described as a layer made up of Ag(4)O(P)(6) clusters linked by O-P-O units and AgAg contacts, with the organic groups grafted on the two sides of the inorganic layer. A similar layer structure is found in 2 except that the AgAg interactions are absent. Compound 3 shows a chain structure where the silver ions are bridged by the phosphonate oxygen atoms forming an infinite Ag-O(P) chain which is decorated by the pyrophosphonate ligand and CH(3)CN. Compound 4 has another type of chain structure made up of Ag-O(P) with extensive Ag···Ag argentophilic interactions. Solid state photoluminescent properties and thermal expansion behaviors are also investigated.

Metal phosphonates based on bis(benzimidazol-2-ylmethyl)imino methylenephosphonate: from discrete dimer to two-dimensional network containing metallomacrocycles.

Hydrothermal reactions of bis(benzimidazol-2-ylmethyl)imino(methylenephosphonic acid) {[(C(7)H(5)N(2))CH(2)]2NCH(2)PO(3)H(2), bbimpH2} with metal salts result in four new compounds, namely, Mn2{[(C(7)H(5)N(2))CH2]2NCH(2)PO(3)}2(H2O)2.2H2O (1), Cd2{[(C(7)H(5)N(2))CH2]2NCH(2)PO(3)}2.2H2O (2), Fe2{[(C(7)H(5)N(2))CH2]2NCH(2)PO(3)}2.H2O (3), and CuI(2){[(C(7)H(5)N(2))CH2]2NCH(2)P(OH)O2}2 (4). Compounds 1 and 2 have dinuclear structures in which two {MN(3)O(3)} octahedra are linked through edge sharing. In compound 3, a chain structure is observed where the {FeN(3)O(2)} trigonal bipyramids are linked by {CPO(3)} tetrahedra through corner-sharing. The structure of compound 4 is unique. The monovalent Cu(I) ions are connected by the imidazole nitrogen atoms from the bbimp(2-) ligands forming a 16-member metallomacrocycle. These metallomacrocycles are further connected by the phosphonate oxygen atoms, leading to a two-dimensional net containing 16- and 32-member rings. Magnetic studies of 1 and 3 reveal that weak ferromagnetic interactions are mediated between magnetic centers in compound 1, while antiferromagnetic interactions were observed in compound 3.