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A series of Cu(II), Ag(I), Zn(II) and Cd(II) complexes of new pyridyl-pyrazinyl ketones 2-pyridinyl-2-pyrazinylmethanone (abbreviated as L1), 3-pyridinyl-2-pyrazinylmethanone (L2) and 4-pyridinyl-2-pyrazinylmethanone (L3) has been synthesized and characterized by single crystal X-ray analysis. L1 can takes not only its neat ketone form in [Ag(L1)(NO 2 )] ∞ ( 1 ), but also the gem -diol form (L1 a ) in [Ag(L1 a )(CF 3 CO 2 )] ∞ ( 2 ) and [Cu(L1 a ) 2 ](BF 4 ) 2 ·4H 2 O ( 3 ) via in-situ metal-promoted nucleophilic reaction. L2 and L3 preferentially adopt their ketone forms in zinc(II) and cadmium(II) complexes [Zn(L2) 2 Cl 2 ] ( 4 ), [Cd(L2) 2 (NO 3 ) 2 (H 2 O) 2 ] ( 5 ), {[Cd(L2) 2 (H 2 O) 2 ](BF 4 ) 2 ·4H 2 O} ∞ ( 6 ), {[Cd(L2) 2 (H 2 O) 2 ](ClO 4 ) 2 ·4H 2 O} ∞ ( 7 ), [Cd(L3) 2 (H 2 O) 4 ](NO 3 ) 2 ( 8 ) and {[Cd 4 (L3) 4 (ClO 4 ) 2 ](ClO 4 )6⋅13H2O} ∞ ( 9 ). The ligand behavior of L1–L3 in complexes 1 – 9 are compared to that of di-2-pyridinylmethanone and its positional isomers. The metal-promoted nucleophilic reaction mechanism involving the carbonyl group in coordination complexes of the pyridyl ketone family is probed and discussed. Supramolecular architectures of complexes 1 – 9 with the various ketones are also observed and discussed. [ABSTRACT FROM AUTHOR]

A family of Ag(I) complexes constructed from the unsymmetrical bent-shaped ligand 2-(pyridine-4-ylthio)pyrazine (abbreviated as 2-PTP), namely [Ag(2-PTP) 2 ]·ClO 4 ( 1 ), {[Ag 2 (2-PTP) 2 (CF 3 CO 2 ) 2 ]·(H 2 O)} ∞ ( 2 ), {[Ag(2-PTP)(NO 2 )]} ∞ ( 3 ), {[Ag 3 (2-PTP) 2 (CF 3 SO 3 ) 2 ]·(CF 3 SO 3 )·(H 2 O)} ∞ ( 4 ) and {[Ag 2 (2-PTP) 2 (SO 4 )]·9H 2 O} ∞ ( 5 ), has been synthesized by varying the silver(I) salts. These complexes have been characterized by single crystal X-ray diffraction, FT-IR spectra and elemental analyses. In 1 – 5 , the 2-PTP ligand adopts versatile coordination modes with various silver(I) salts to generate a series of supramolecular architectures. Weak interactions, such as hydrogen bonding and π ⋯ π interactions, have been described in detail. The anion influence on the structural diversities of 1 – 5 has also been discussed. [ABSTRACT FROM AUTHOR]

Abstract: A series of silver(I) complexes bearing the V-shaped di-4-pyridyl sulfone-N,N′-dioxide ligand (abbreviated as L), namely [Ag(L)(NO3)(H2O)]∞ (1), [Ag(L)(CF3SO3)]∞ (2), [Ag(L)(CF3CO2)]∞ (3), [Ag(L)(C2F5CO2)]∞ (4) and {[Ag(L)](ClO4)}∞ (5), and the manganese(II) complex [Mn(L)2(H2O)4](ClO4)2 (6) and the zinc(II) complex [Zn(L)2(H2O)4](ClO4)2 (7) of L have been synthesized and characterized. Under the tuning effect of anions with different coordination capacities and steric bulk, the semi-rigid ligand L exhibits versatile μ2-, μ3- and μ4-bridging modes with the N-oxide and/or sulfonyl O atoms functioning as bonding sites to form a coordination chain structure in complex 1, isostructural nets in 2–4, and a three-dimensional framework in 5. The isostructural mononuclear complexes 6 and 7 exhibit the η1–ON-oxide bonding mode of L. Unusual lone-pair aromatic contacts and anion–π interactions result in supramolecular aggregations of complexes 1–7. The FT-IR spectra and luminescent properties of these complexes have been observed and discussed. [Copyright &y& Elsevier]