The field of diborinane is sparsely explored area, and not many compounds are structurally characterized. The room-temperature reaction of [{Cp*RuCl­(μ-Cl)}2] (Cp* = η5-C5Me5) with Na­[BH3(SCHS)] yielded ruthenium dithioformato [{Cp*Ru­(μ,η3-SCHS)}2], 1, and 1-thioformyl-2,6-tetrahydro-1,3,5-trithia-2,6-diborinane complex, [(Cp*Ru)­{(η2-SCHS)­CH2S2(BH2)2}], 2. To investigate the reaction pathway for the formation of 2, we carried out the reaction of [(BH2)4(CH2S2)2], 3, with 1 that yielded compound 2. To the best of our knowledge, it appears that compound 2 is the first example of a ruthenium diborinane complex where the central six-membered ring [CB2S3] adopts the chair conformation. Furthermore, room temperature reaction of 1 with [BH3·thf] resulted in the isolation of agostic-bis­(σ-borate) complex, [Cp*Ru­(μ-H)2BH­(S-CHS)], 4. Thermolysis of 4 with trace amount of tellurium powder led to formation of bis­(bridging-boryl) complex, [{Cp*Ru­(μ,η2-HBS2CH2)}2], 5, via dimerization of 4 followed by dehydrogenation. Compound 5 can be considered as a bis­(bridging-boryl) species, in which the boryl units are connected to two ruthenium atoms. Theoretical studies and chemical bonding analyses demonstrate the reason for exceptional reactivity and stability of these complexes.

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Syntheses, structures, and electronic properties of group 5 metal–thiolate complexes that exhibit unusual coordination modes of thiolate ligands have been established. Room-temperature reaction of [Cp*VCl2]3 (Cp* = η5-C5Me5) with Na5[B­(SCH2S)4] led to the formation of [Cp*VO­{(SCH2)2S}] (1). The solid-state X-ray structure of 1 shows the formation of six-membered l,3,5-trithia-2-vanada­cyclo­hexane that adopted a chair conformation. In a similar fashion, reactions of heavier group 5 precursors [Cp*MCl4] (M = Nb or Ta) with Na5[B­(SCH2S)4] yielded bimetallic thiolate complexes [(Cp*M)2(μ-S)­{μ-C­(H)­S3-κ2 S:κ2 S′,S″}­{μ-SC­(H)­S-κ2 C:κ2 S‴,S′′′′}] (3a: M = Nb and 3b: M = Ta). One of the key features of molecules 3a and 3b is the presence of square-pyramidal carbon, which is quite unusual. The reactions also yielded bimetallic methanedithiolate complexes [(Cp*Nb)2(μ-S)­(μ-SCH2S-κ2 S,S′)­(μ,η2:η2-BH3S)] (2) and [(Cp*Ta)2(μ-O)­(μ-SCH2S-κ2 S,S′)­(μ-H)­{μ-S2C­(H)­SCH2S-κ2 S″:κ2 S‴,S′′′′}] (4). Complex 2 contains a methanedithiolate ligand that stabilizes the unsaturated niobaborane species. On the other hand, one ((mercapto­methyl)­thio)­methane­di­thiolate ligand {C2H4S3} is present in 4, which is coordinated to metal centers and exhibits the {μ-κ2 S″:κ2 S‴,S′′′′} bonding mode. Along with the formation of 3b and 4, the reaction of [Cp*TaCl4] with Na5[B­(SCH2S)4] yielded [(Cp*Ta)2(μ-S)­{μ-(SBS)­S­(CH2S)2(BH2S)-κ2 B:κ2 S:κ4 S′,S″,S‴,S′′′′}] (5) containing a trithiaborate unit (BS3). Complex 5 consists of pentacoordinate boron that resides in a square-pyramidal environment. All the complexes have been characterized by multinuclear NMR, UV–vis spectroscopy, mass spectrometry, and single-crystal X-ray diffraction studies.

A series of hydroborated η4-σ,π-alkene–borane complexes have been synthesized from the reaction of ruthenium–bis­(σ)­borate complex [Cp*Ru­(μ-H)2BH­(S-CHS)] (1) and terminal as well as internal alkynes. Likewise, the reactions of manganese–bis­(σ)­borate complexes [Mn­(CO)3(μ-H)2BHNCSC6H4(NL)] (L = NCSC6H4 or H) were explored with terminal alkynes that yielded boratabutadiene complexes [Mn­(CO)3{(NCSC6H4)2N}­{(R1MeC)B­(HCCHR1)}] [R1 = phenyl (4a) or p-tolyl (4b)] via triple hydroboration of alkynes. These complexes feature a boratabutadiene ligand that is coordinated to a metal through the η4-CBCC mode. To the best of our knowledge, these are the first examples of η4-E-boratabutadiene-coordinated manganese complexes generated by the trans-hydroboration of alkynes. The steric and electronic effects of the borate ligands have been demonstrated using a less sterically hindered manganese–bis­(σ)­borate complex, [Mn­(CO)3(μ-H)2BH­(HN2CSC6H4)], that generated monohydroborated complexes [(CO)3Mn­(μ-H)2(HN2CSC6H4)­B­(R1CCHR2)] (for 6, R1 = Ph and R2 = H; for 7, R1 = p-Tol and R2 = H; for 8, R1 = R2 = Ph). Theoretical studies using density functional theory methods and chemical bonding analyses established the bonding and stability of these species.

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The canteen and laboratory of every academic organization need a lot of clean water, and it generates equivalent amount of wastewater every hour which is neither purified nor reused. Due to water scarcity, the recycling and reusing of wastewater become very essential. The present study describes the simple and cost-effective method for the design of a small-scale wastewater treatment plant for the purification of wastewater generated by household, canteen and laboratory of an academic institute. The current study explored the process of phytoremediation by Typha latifolia L. and Canna indica L. for removal of metal ions and phosphate ions from the wastewater. The partially treated water after phytoremediation was further purified by sand filtration. The various water quality parameters (pH, hardness, dissolved oxygen, chemical oxygen demand, turbidity, total dissolved solids and metal ions) of the treated and untreated water were analyzed. It was observed that there are significant reduction in hardness, turbidity and chemical oxygen demand and increase in dissolved oxygen value. The treated water can be reused for various household works and agriculture.

New synthetic route for the synthesis of diruthenium boryl complexes has been established. Thermolysis of an arachno-ruthenaborane, [(Cp*Ru)2B3H8( CS2H)] (1) (Cp* = η 5 -C5Me5) with phenyl acetylene, led to the formation of bridging boryl borylene complex as [(Cp*Ru)2(µ-HBS2CH2-κ 2 B:κ 2 S){µ-B(C6H4)C(CH3)-κ 2 B:κ 2 C}] (2). In parallel to the formation of 2, the reaction also yielded [(Cp*Ru)(μ-H)BH{HC=C(H)Ph}{SC(H)S}] (3a) and [(Cp*Ru)(μ-H)BH( PhC=CH2){SC(H)S}] (3b). To understand the reaction pathways for the formation of 2, we have thermolyzed 1 in toluene that afforded ruthenium bridging bis(boryl) complex, [(Cp*Ru)2(µ-HBS2CH2-κ 2 B:κ 2 S){µ,η 2 :η 2 -SBH}] (4) along with nido-ruthenathiaborane [(Cp*Ru)2(Me)-(S2B2H3)] (5). Nido-5 is structurally and electronically similar with nido-[(Cp + Ru)2( S2C2Ph2)] (Cp + = η 5 -C5Me4Et), which can be generated from the room temperature reaction of [(Cp + Ru)2(μ,η 1 :η 1 -S2)(μ,η 2 :η 2 -S2)] with diphenylacetylene. Thus, nido-5 can be defined as a true mimic of organometallic cluster nido-[(Cp + Ru)2(S2C2Ph2)]. Complex [(Cp*Ru)2(μ,η 1 :η 1 -S2)(μ,η 2 :η 2 -S2)] ( 6) the Cp* analogue of [(Cp + Ru)2(μ,η 1 :η 1 -S2)(μ,η 2 :η 2 -S2)], can be isolated from the reaction of Li[BH2S3] with [Cp*RuCl2]2 along with a diruthenium boryl complex, [(Cp*Ru)2(μ,η 1 :η 1 -S2)(μ-S2BH-κ 1 B:κ 2 S:κ 2 Sʹ)] (7) in which the boryl unit (S2BH) possesses no bulky heterocyclic ligand. Theoretical studies were performed to shed light on the bonding of these borylene and boryl complexes. The theoretical calculations reveal that the stability of these complexes is due to the strong interaction between the borylene and boryl unit with the ruthenium centers.4, 5, 6 and 7. This material is available free of charge via the internet at http://pubs.acs.org.

The thermolysis of arachno-1 [(Cp*Ru)2(B3H8)(CS2H)] in the presence of tellurium powder yielded a series of ruthenium trithia-borinane complexes: [(Cp*Ru)2(η1-S)(η1-CS){(CH2)2S3BH}] 2, [(Cp*Ru)2(η1-S)(η1-CS){(CH2)2S3B(SMe)}] 3, and [(Cp*Ru)2(η1-S)(η1-CS){(CH2)2S3BH}] 4. Compounds 2–4 were considered as ruthenium trithia-borinane complexes, where the central six-membered ring {C2BS3} adopted a boat conformation. Compounds 2–4 were similar to our recently reported ruthenium diborinane complex [(Cp*Ru){(η2-SCHS)CH2S2(BH2)2}]. Unlike diborinane, where the central six-membered ring {CB2S3} adopted a chair conformation, compounds 2–4 adopted a boat conformation. In an attempt to convert arachno-1 into a closo or nido cluster, we pyrolyzed it in toluene. Interestingly, the reaction led to the isolation of a capped butterfly cluster, [(Cp*Ru)2(B3H5)(CS2H2)] 5. All the compounds were characterized by 1H, 11B{1H}, and 13C{1H} NMR spectroscopy and mass spectrometry. The molecular structures of complexes 2, 3, and 5 were also determined by single-crystal X-ray diffraction analysis.