Alkali metal salts of a novel Janus scorpionate ligand [(Tr(Me))](-) with hard and soft donor sites (N, S) were synthesized by the reaction of 3-mercapto-4-methyl-1,2,4-triazole (L) with NaBH4 and KBH4, respectively, via Trofimenko's protocol. The resulting compounds were the sodium and potassium complexes [Na(Tr(Me))] (1), [K(Tr(Me))] (2) and the mixed ion compound [KNa(Tr(Me))] (3). [K(Tr(Me))] (2) was reacted with bismuth(III) chloride to afford the complexes [Bi(Tr(Me))(Cl)(μ-Cl)2]2 (5) and [Bi(Tr(Me))(Cl)2(μ-Cl)]n (6). Compound 5 was formed when 2 was applied to BiCl3 in a molar ratio 2:1, while 6 was achieved when a ratio of 1:1 was used. The reaction of 3-mercapto-4-methyl-1,2,4-triazole (L) with BiCl3 led to the formation of the complex [Bi(L)4(Cl)2]Cl (7). The products were characterized by NMR and IR spectroscopy, elemental analyses and mass spectrometry. Solid state structures were determined by X-ray diffraction of single crystals of 1, 3, 3a, 5, 6 and 7. The alkali metal scorpionates 1-3 are coordination polymers with alternating orientation of the ligands. They dissociate in solution as observed in NMR measurements. Negative mode ESI-MS data also indicate the presence of monomers. The bismuth complex 5 is dimeric and 6 is polymeric, and both are bridged via chloro ligands. The three bismuth complexes 5, 6 and 7 have highly distorted octahedral coordination geometries. The influence of the stereochemically active lone pair was found to be most pronounced in the dimeric complex 5. The ligand Tr(Me) and all bismuth complexes were also screened for their photo-luminescence activity. Whereas solutions of Tr(Me) exhibit no luminescence, 7 is only emissive at 77 K, and 5 is emissive both at r.t. and 77 K.

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Two novel sodium complexes [NaBb] (1) (Bb = dihydrobis(2-mercapto-benzimidazolyl)borate) and [NaBt(Me)] (2) (Bt(Me) = dihydrobis(2-mercapto-4-methylthiazolyl)borate) have been prepared and characterized by using two heterocycles, 2-mercapto-benzimidazole and 2-mercapto-4-methylthiazole, as well as NaBH4 as precursors. The dipodal boron centred soft ligands Bb and Bt(Me) were prepared in situ. The reactivity of [NaBb] (1) and [NaBt(Me)] (2) towards Bi(III) ions has been studied. The resulting complex [BiBb2Cl] (3) contains an MS4 core with κ(3)-S,S,H coordination mode, while the complex [BiBt(Me)3] (4) with an MS6 core adopts a coordination mode κ(2)-S,S. A reaction of BiCl3 with the heterocyclic precursors 2-mercapto-benzimidazole (L(1)) and 2-mercapto-4-methylthiazole (L(2)) was also attempted; this afforded the monomeric [BiL(1)4Cl2][BiL(1)2Cl4] (5) and dimeric [BiL(2)2(μ-Cl)Cl]2 (6) bismuth complexes. The bismuth complexes possess distorted octahedral geometries except 3 for which a face-capped octahedron is found. The presence of (B)H···Bi interactions has been identified by X-ray diffraction in 3 with a H···Bi distance of 2.58(1) Å which is uniquely short and unprecedented. Two of the synthesized complexes (4 and 5) have been investigated by luminescence spectroscopy. They feature emission bands in the solid state at room temperature at 674 (4) and 586 nm (5), which are hypsochromically shifted in (frozen) ethanolic solutions at 77 K to 618 and 537 nm, respectively.

To investigate the geometry and stereochemical activity of the lone pair at the lead atom, lead(ii) complexes () with one tripodal (L(1)), one dipodal (L(2)) boron-centred soft ligand and eight other small soft heterocyclic ligands, 2-mercaptobenzimidazole (L(3)), 2-mercapto-5-methylbenzimidazole (L(4)), 3-mercapto-1,2,4-triazole (L(5)H), 3-mercapto-4-methyl-1,2,4-triazole (L(6)), 2-mercapto-1,3,4-thiadiazole (L(7)H), 2-mercapto-5-methyl-1,3,4-thiadiazole (L(8)H), 5-mercapto-1-methyltetrazole (L(9)H) and 2-mercapto-4-phenylthiazole (L(10)H) were prepared. The structures of these complexes were elucidated on the basis of X-ray crystallography, elemental analyses as well as (1)H NMR, (1)H DOSY, (13)C NMR and (207)Pb NMR spectroscopy. The coordination numbers of these complexes vary from 4 to 8. The majority of the complexes are polymeric and possess a hemi-directed environment around the lead atoms. Solution studies revealed that most of the complexes are dissociated in highly polar solvents. Most of the complexes are emissive both under ambient conditions and at 77 K in the solid state. However, no obvious relationship between their solid state structures and luminescence behaviour with respect to the nature of the excited state could be identified.

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Three new lead based organic frameworks, [Pb(C6H6O2S2N)2] (1), [Pb(C12H6O4).(H2O)]n (2), [Pb(C14H8O4)]n (3) have been synthesized via hydro/solvothermally using 2‐mercapto‐3‐methyl‐4‐thiazoleacetic acid (H2MMTA), 2,6‐naphthalenedicarboxylic acid (2,6‐NDA) and biphenyl‐4,4′‐dicarboxylic acid (H2BDA) as organic precursors. The resulting metal organic frameworks (MOFs) were characterized by UV/Vis, Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), 1H NMR, Energy dispersive spectroscopy (EDS), Thermogravimetric analysis (TGA) and Powder X‐ray diffraction technique. MOF (1) has also been characterized by single‐crystal X‐ray diffraction method which exhibited a three‐dimensional (3D) framework with an octahedral hemidirected environment around each Pb2+ ion. All these MOFs (1 − 3) were screened for their luminescence activity. This luminescence activity has been assigned to metal‐centred s→p transition in case of MOF (1) and ligand‐to‐metal charge transfer (LMCT) in case of MOFs (2 & 3). Adsorption of N2 gas by these MOFs was investigated and the results of this study are also part of this manuscript.

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The syntheses of Na(Ttt(Me)) (), K(Ttt(Me)) (), K(Btt(Me)) (), and Na(Btt(Ph)) () are reported, where (Ttt(Me))(-) and (Btt(R))(-) (R = Me, Ph) are tri- and di-substituted boron-centered soft ligands; they were produced by the reaction of NaBH4 and KBH4 with the corresponding tetrazole heterocycles: 1-methyl-5-thiotetrazole (L(1)H) and 1-phenyl-5-thiotetrazole (L(2)H). The syntheses of Na(Ttt(Me)) () and K(Ttt(Me)) () were carried out following Trofimenko's protocol. The anion (Ttt(Me))(-) is a typical Janus scorpionate ligand. Na(Ttt(Me)) () and Na(Btt(Ph)) () were reacted with Bi(CH3COO)3 to observe the coordination pattern of these ligands towards bismuth ions. These reactions afforded the complexes [Bi(Ttt(Me))2(CH3COO)] (), [Bi(L(2))2]2 (, ) and [Bi(L(2))3] (). The products were characterized by NMR spectroscopy, elemental analyses and mass spectrometry. Solid state structures were determined by X-ray diffraction of single crystals of , , , , , , and . M(Ttt(Me)) (M = Na (), K ()) and K(Btt(Me)) () exhibit sheet-like structures. The alkali metal complexes dissociate in solution as observed in (1)H, (13)C NMR and (1)H diffusion NMR experiments. Negative mode ESI-MS data also indicate the presence of monomers. Both the sodium salts of (Ttt(Me))(-) and (Btt(Ph))(-) as well as the Bi complexes and were investigated by absorption and emission spectroscopy.