THE N-DONOR BIDENTATE LIGANDS CONTAINING EXO NITROGEN ATOMS SUCH AS 4, 4′-BIPYRIDINE, 2, 2′-BIPYRINE ARE WIDELY USED FOR THE PREPARATION OF DINUCLEAR AND POLYNUCLEAR COMPOUNDS 1. ON THE OTHER HAND...

THE UTILITY OF METALATED PHOSPHORUS YLIDES IN THE SYNTHETIC CHEMISTRY HAS BEEN WELL DOCUMENTED [1]. IN 1975, WELESKI ET AL. [2] PROPOSED A HALIDE-BRIDGED DIMERIC STRUCTURE FOR HG (II) HALIDE COMPLEXES OF PHOSPHORUS YLIDES WITH EQUAL BRIDGED BONDS, WHEREAS KALYANASUNDARI ET AL. IN 1995 [3] REPORTED CENTROSYMMETRIC HALIDE-BRIDGED DIMERIC STRUCTURES WITH UNEQUAL BRIDGED BONDS. WE HAVE RECENTLY FOCUSED ON THE BINUCLEAR [4] AND POLYNUCLEAR [5] COMPLEXES DERIVED FROM MERCURY (II) SALTS AND PHOSPHORUS YLIDES. THE MONODENTATE PHOSPHORUS YLIDE OF (PTOLYL) 3P=C(H)C(O)C6H4(M-OCH3) (Y) IS PREPARED BY THE REACTION OF BRCH2C(O)C6H4(M-OCH3) WITH TRI-P-TOLYLPHOSPHINE (P-TOLYL)3 IN ACETONE AS SOLVENT. THE REACTION OF LIGAND (Y) WITH HG (II) HALIDES IN METHANOL LEADS TO BINUCLEAR PRODUCTS [(Y). HGX2]2, WHERE X=CL(1), BR(2), I(3). CHARACTERIZATION OF THE OBTAINED COMPOUNDS WAS ALSO PERFORMED BY ELEMENTAL ANALYSIS, IR AND MULTINUCLEAR NMR MEASUREMENTS.

PHOSPHORUS YLIDES ARE REACTIVE COMPOUNDS, WHICH TAKE PART IN MANY REACTIONS OF VALUE IN THE SYNTHESIS OF ORGANIC PRODUCTS [1]. THEY ARE SYNTHETIC TARGETS OF INTEREST, BECAUSE OF THEIR VALUE FOR A VARIETY OF INDUSTRIAL, BIOLOGICAL AND CHEMICAL SYNTHETIC USES [2]. THE SYNTHESIS OF COMPLEXES DERIVED FROM YLIDES AND AG (I) BEGAN IN 1975 BY YAMAMOTO ET AL.[3]. OTHER TYPES OF YLIDE COMPLEXES OF SILVER (I) HAVE BEEN REPORTED [4,5]. IN 2007, WE REPORTED THE FIRST HG (II) NITRATE POLYMERIC COMPLEXES WITH THESE YLIDES [6], WHERE IN THE NITRATE ANIONS ARE BRIDGING, CONFIRMING THE GENERAL BELIEF THAT SEVEN-COORDINATED COMPLEXES WOULD BE FORMED. WE HAVE RECENTLY FOCUSED ON THE BINUCLEAR [7] AND POLYNUCLEAR [8] COMPLEXES DERIVED FROM MERCURY (II) AND SILVER (I) SALTS AND PHOSPHORUS YLIDES. IN THIS STUDY WE REPORT THE REACTION OF PHOSPHORUS YLIDE (PTOLYL)3P=C(H)C(O)C6H4(M-OCH3) (Y) WITH HG (II) NITRATE IN EQUIMOLAR RATIOS AND AG(I) IN 1:2 RATIOS USING METHANOL AS SOLVENT LEADS TO BINUCLEAR PRODUCTS {Y[HG(NO3)2]2} AND [AG(Y2)2(NO3)]. CHARACTERIZATION OF THE OBTAINED COMPOUNDS WAS PERFORMED BY ELEMENTAL ANALYSIS, IR AND MULTINUCLEAR NMR MEASUREMENTS.

BACKGROUND: ORGANIC, INORGANIC CARBOXYLATES AND THEIR DERIVATIVES ARE WIDELY USED IN MODERN INDUSTRIAL, BIOLOGICAL, AND SYNTHETIC PROCESSES. THE UNIVERSALITY OF CARBOXYLIC ACIDS AS LIGANDS AND THE BINDING OF THEIR ACID RESIDUES (MONODENTATE AND BIDENTATE EITHER BY CHELATION, OR BY FORMING BRIDGES) FAVOR THE EXISTENCE OF A GREAT VARIETY OF CARBOXYLATE-BASED COMPLEXES [1-4]...

AMINE AND THIONE SUBSTITUTED TRIAZOLES HAVE BEEN STUDIED AS ANTI-INFLAMMATORY AND ANTIMICROBIAL AGENT S[1]. IN ADDITION 1,2,4- TRIAZOLES DISPLAY A BROAD RANGE OF BIOLOGICAL ACTIVITIES, SUCH AS ANTITUMOR, ANTIBACTERIAL, ANTIFUNGAL AGENTS [2]. IN A SEQUENCE OF STUDIES, WE HAVE INVESTIGATED THE SYNTHESES AND CRYSTAL STRUCTURES OF SEVERAL SCHIFF BASE LIGANDS DERIVATIVES HETEROCYCLIC THIONE COMPOUNDS SUCH AS 4-AMINO-6-METHYL-3-THIO-3,4-DIHYDRO- 1,2,4-TRIAZIN-5(2H)-ONE (AMTTO) AND 4-AMINO-5-METHYL-2H-1,2,4-TRIAZOLE-3(4H)-THIONE (AMTT) AND THEIR COPPER(I) AND SILVER(I) COMPLEXES. WE HAVE SHOWN THAT FOR AG (I), THESE SCHIFF BASE LIGANDS ACT AS A BIDENTATE LIGAND VIA SULFUR AND AZOMETHINE NITROGEN ATOM. WHILE FOR CU (I) ION, ACT AS A MONODENTATE LIGAND VIA SULFUR. WE HAVE STUDIED ALSO SYNTHESIZED AND CHARACTERIZED COMPLEXES AGAINST THE NUCLEOPHILE PPH3 AS A CO-LIGAND [3- 5]. HERE WE REPORT THE PREPARATION AND CHARACTERIZATION OF A NEW SILVER (I) COMPLEX WITH A SCHIFF BASE BASED ON AMTT. 4-(2,4-DICHLOROBENZYLIDENEAMINO)-5-METHYL-3-THIOXO-2H- 1,2,4-TRIAZOLE (L) WAS SYNTHESIZED ACCORDING TO LITERATURE [1]. THE REACTION OF L WITH AGNO3 AND TRIPHENYLPHOSPHINE (IN MOLAR RATIO 1:1:1) METHANOL /CHLOROFORM (2:1) LED TO [AG(L)(PPH3)3] .CH3OH. THE SYNTHESIS COMPLEX WAS CHARACTERIZED BY IR AND NMR SPECTROSCOPY AND AS WELL AS BY X-RAY DIFFRACTION STUDIES. AS WAS SHOWN IN FIGURE1. L ACTS AS A MONODENTATE LIGAND VIA SULFUR AND DISTORTED TETRAHEDRON AROUND AG (I) ION IS COMPLETED WITH PHOSPHOR ATOMS OF THREE PPH3 LIGANDS. CRYSTALIZE IN THE MONOCLINIC P21/C SPACE GROUP.

INTRODUCTION THE IMIDAZOLE RING HAS TWO ADJACENT NUCLEOPHILIC SITES AND ITS STERIC AND ELECTRONIC PROPERTIES CAN BE MODIFIED BY THE SUBSTITUENTS AT DIFFERENT POSITIONS ON THE RING. THE IMIDAZOLE CAN COORDINATES AS A MONODENTATE LIGAND TO THE METAL IONS VIA THE PYRIDINE-TYPE NITROGEN. HOWEVER THE PYRROLE-TYPE NITROGEN (N-H) CAN FORM HYDROGEN BONDS WITH HYDROGEN ACCEPTOR AND/OR HYDROGEN DONOR POSITIONS. ON THE OTHER HAND, THE IMIDAZOLATE ANION CAN FUNCTION AS A BRIDGE LIGAND THROUGH BOTH NITROGENS AFFORDING POLYNUCLEAR COMPLEXES OF INTRIGUING STRUCTURAL DIVERSITIES, PROPERTIES AND REACTIVITIES, NOT FOUND FOR MONONUCLEAR COMPLEXES.

BACKGROUND: THE LINEAR THIOCYANATE GROUP CAN BE PRESENT IN COMPOUNDS AS AN ANION OR AS A LIGAND A MONODENTATE LIGAND COORDINATED TO SULFUR OR NITROGEN, OR ABRIDGING LIGAND. THE GREAT COORDINATION ABILITY OF THE THIOCYANATE GROUP AND A GREAT VARIETY OF ITS BONDING MODES ARE RESPONSIBLE FOR THE EXISTENCE OF A RELATIVELY GREAT NUMBER OF COORDINATION COMPOUNDS IN LIQUID AND SOLID STATE IN WHICH THIS GROUP OCCURS.SEVERAL AUTHORS GATHERED TOGETHER INFORMATION AVAILABLE ON THESE COMPOUNDS AND DISCUSSED THEM IN SEVERAL REVIEW ARTICLES. [1] SYNTHESIS OF IRON (II) COMPLEXES WITH A COMBINATION OF NITROGEN-DONOR LIGANDS IN 2004 BYP. KOPEL ET AL. [2]...