Reactions of unsaturated [HOs3(CO)8{µ3-Ph2PCH(R)P(Ph)C6H4}] (R?=?H, Me) with Bu3SnH are examined. [HOs3(CO)8{µ3-Ph2PCH(R)P(Ph)C6H4}] reacts with Bu3SnH at room temperature to afford [H2Os3(CO)8(SnBu3){µ3-Ph2PCH(R)P(Ph)C6H4}] (1) via oxidative addition of the Sn?H bond to the parent cluster. Heating 1 in refluxing toluene leads to the formation of [H2Os3(CO)7(SnBu3){µ3-Ph2PCH(R)P(Ph)C6H4}] (2) through decarbonylation. Cluster 2 exists in two isomeric forms in solution which has been probed by VT NMR spectroscopy. The new Os-Sn bimetallic clusters have been characterized by a combination of analytical and spectroscopic data together with single-crystal X-ray diffraction analysis.
Graphic abstractThe 2:1 molar reaction of [Fe2(CO)6{(µ-SCH2)2CH2}] (1) and a bidentate diphosphine ligand, 1,6-bis(diphenylphosphino)hexane (dpph), in the presence of Me3NO resulted in the isolation of [Fe2(CO)5{Ph2P(CH2)3}{(µ-SCH2)2CH2}]2 (2) as red crystals in 71?% yield. The dpph ligand in compound 2, coordinates two Fe2S2 subunits as bridging mode and hence makes a linkage between two [Fe2(CO)5{(µ-SCH2)2CH2}] fragments. Each Fe2S2 butterfly of the complex consists of two fused Fe(S-C-C-C-S) six-membered rings, one of which attains a chair conformation, and the other is necessarily in a boat conformation. Compound 2 has unequivocally been characterized by elemental analysis, IR, 1H NMR and 31P NMR spectroscopy together with single crystal X-ray diffraction studies. Crystals of 2 are triclinic, space group P-1, a = 9.918(4) Å, b = 10.347(3) Å, c = 14.581(5) Å, α?=?72.239(12)º, β?=?80.342(12)º, γ?=?68.550(14)º and Z = 1.
Graphic AbstractA novel tetranuclear propane-1,3-dithiolate complex, [Fe2(CO)5{Ph2P(CH2)3}{(μ-SCH2)2CH2}]2 (2), bearing a bridging bis(diphenylphosphino)hexane (dpph) ligand, was synthesized from the Me3NO aided room temperature displacement of carbonyls from [Fe2(CO)6{(μ-SCH2)2CH2}] (1), and structurally characterized.
Treatment of [Fe2(CO)6(μ-S2C3H6)] (1) with triphenylstibine in a 1:1 molar ratio at room temperature in presence of Me3NO resulted compound [Fe2(CO)5(SbPh3)(μ-S2C3H6)] (2) in 88% yield as red crystals. When the reaction was carried out under a 1:5 molar ratio in presence of Me3NO, it resulted a monosubstituted compound [Fe2(CO)5(SbPh3)(μ-S2C3H6)] (2) in 63% yield along with a disubstituted compound [Fe2(CO)4(SbPh3)2(μ-S2C3H6)] (3) in low yield (8%) as red crystals. Reaction of 2 with triphenylstibine in a 1:5 molar ratio under same condition resulted 3 in moderate yield (46%). Compounds 2 and 3 were characterized by elemental analyses, IR, 1H NMR and 13C NMR spectroscopic data. Crystal structures of the compounds were unambiguously determined by single crystal X-Ray diffraction studies. Compound 2 crystalized as monoclinic crystal system with the space group P21/c, a?=?9.464(4) Å, b?=?16.902(7) Å, c?=?17.081(7) Å, β?=?101.216(13)° and Z?=?4. Compound 3 was triclinic, space group P-1, a?=?9.552(3) Å, b?=?13.985(5) Å, c?=?16.487(6) Å, α?=?78.372(16)°, β?=?89.976(14)°, γ?=?71.638(11)° and Z?=?2.
Graphic AbstractTwo new diiron propane-1,3-dithiolate complexes, [Fe2(CO)5(SbPh3)(μ-S2C3H6)] (2) and [Fe2(CO)4(SbPh3)2(μ-S2C3H6)] (3), were synthesized by the displacement of carbonyl groups from [Fe2(CO)6(μ-S2C3H6)] (1) with triphenylstibine, and the resulting complexes were structurally characterized.
Solid state molecular structure of compound 2 (left) and compound 3 (right)
Air radon survey was carried out at different underground locations at Kolkata using radon monitor. Average radon concentration for basements was found to be 22.70 ± 1.12 Bq/m3 with maximum 59.00 ± 7.18 Bq/m3 and minimum 8.50 ± 3.14 Bq/m3. Average level for sub-ways was 23.05 ± 2.59 Bq/m3 fluctuating between maximum 39.00 ± 1.24 Bq/m3 and minimum 13.50 ± 1.78 Bq/m3. In comparison, open air background at basement entrance was 19.44 ± 1.06 Bq/m3 and subway entrance was 18.58 ± 1.14 Bq/m3. Annual effective dose was calculated to assess probable health risk. Radon concentration level and annual effective dose were found well below safe levels recommended by International Agencies WHO and UNSCEAR.
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