A series of novel Cp*-based (Cp*=η5-C 5Me5) agostic, bis(σ-borate), and boratrane complexes have been synthesized from diruthenium and dirhodium analogues of pentaborane(9). The synthesis and structural characterization of the first neutral ruthenadiborane(6) analogue are also reported. This new route offers a very efficient method for the isolation of bis(σ-borate) and agostic complexes from diruthenapentaborane(9). © 2014 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

Sundargopal Ghosh

Department Of Chemistry

Bijan Mondal

Kuppusamy Yuvaraj

C. Arivazhagan

Koushik Saha

Babu Varghese

AGOSTIC BORANES

BORATRANES

DIRHODIUM

Diruthenium

Structural characterization

Boron Compounds

Hydrides

Rhodium

ruthenium

Synthesis (chemical)

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IIT Madras

Angewandte Chemie - International Edition

The complexes with fac-[M(CO)3]+ units of group-7 metals are interesting synthons for the development of target-specific drugs. Therefore, thermolysis reaction of Re2(CO)10 with various borate ligands have been investigated as a possible route to isolate bis(σ)borate complexes of rhenium. The reaction of trihydrobis(benzothiazol-2-yl)amideborate, Na[(H3B)bbza] (bbza = bis(benzothiazol-2-yl)amine) with Re2(CO)10 led to the formation of distorted octahedral rhenium complexes [(CO)2Re{N(C7H4NS)2}2], 1 and [(CO)2Re{N(C7H4NS)2}{C6H4N(Me)O}], 2. In order to increase the library of complexes containing fac-{M(CO)3}+ moieties as well as to check the lability of the metal–carbonyl bond, reactivity of manganese borate complexes [Mn(CO)3(μ-H)2BHNCSC6H4(NR)], 3 (R = NCSC6H4) and [Mn(CO)3{κ3-S,S′,H-H2B(mbz)2}], 6 (mbz = 2-mercapto-benzothiazolyl) with different ligands were carried out. Photolysis of 3 with excess phosphine ligands (PPh2Me or PMe2Ph) yielded manganese phosphine complexes [Mn(CO)2(PL2L′)2{N(C7H4NS)2}], (4a: L = Ph, L′ = Me; 4b: L = Me, L′ = Ph). Interestingly, the reaction of 3 with tBuNC yielded mono/bis(tBuNC)-substituted manganese borate complexes [Mn(μ-H)2(BHNCSC6H4)(NR)(CO)xLy], 5a–b (5a: x = 2, y = 1; 5b: x = 1; y = 2; L = tBuNC; R = NCSC6H4) and [Mn(μ-H)2BH{N(NCSC6H4)2}(CO)(tBuNC)2], 5c. Compounds 5b and 5c are structural isomers with a different coordination mode of the bbza ligand. Under similar reaction conditions, photolysis of 6 with PPh3 in toluene generated borate complex of manganese [Mn(CO2){κ3-S,S′,H-H2B(mbz)2}(PPh3)], 7. All the compounds were characterised by multi-nuclear NMR, IR spectroscopy and mass spectrometry. Density functional theory (DFT) calculations were carried out to investigate the bonding and electronic structures of these compounds. © 2019 Elsevier Ltd

Fulltext

Polyhedron

Fine tuning of reactivity and structure of bis(σ)borate and borate complexes of manganese by systematic ligand variation

The thermolysis of arachno-1 [(Cp*Ru) 2 (B 3 H 8 )(CS 2 H)] in the presence of tellurium powder yielded a series of ruthenium trithia-borinane complexes: [(Cp*Ru) 2 (η 1 -S)(η 1 -CS){(CH 2 ) 2 S 3 BH}] 2, [(Cp*Ru) 2 (η 1 -S)(η 1 -CS){(CH 2 ) 2 S 3 B(SMe)}] 3, and [(Cp*Ru) 2 (η 1 -S)(η 1 -CS){(CH 2 ) 2 S 3 BH}] 4. Compounds 2-4 were considered as ruthenium trithia-borinane complexes, where the central six-membered ring {C 2 BS 3 } adopted a boat conformation. Compounds 2-4 were similar to our recently reported ruthenium diborinane complex [(Cp*Ru){(η 2 -SCHS)CH 2 S 2 (BH 2 ) 2 }]. Unlike diborinane, where the central six-membered ring {CB 2 S 3 } 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 (B 3 H 5 )(CS 2 H 2 )] 5. All the compounds were characterized by 1 H, 11 B{ 1 H}, and 13 C{ 1 H} NMR spectroscopy and mass spectrometry. The molecular structures of complexes 2, 3, and 5 were also determined by single-crystal X-ray diffraction analysis. © 2019 by the authors.

Inorganics

Synthesis of trithia-borinane complexes stabilized in diruthenium core: [(Cp*Ru) 2 (η 1 -S)(η 1 -CS){(CH 2 ) 2 S 3 BR}] (R = H or SMe)

The room-temperature reaction of [Cp*TaCl4] with LiBH4⋅THF followed by addition of S2CPPh3 results in pentahydridodiborate species [(Cp*Ta)2(μ,η2:η2-B2H5)(μ-H)(κ2,μ-S2CH2)2] (1), a classical [B2H5]− ion stabilized by the binuclear tantalum template. Theoretical studies and bonding analysis established that the unusual stability of [B2H5]− in 1 is mainly due to the stabilization of sp2-B center by electron donation from tantalum. Reactions to replace the hydrogens attached to the diborane moiety in 1 with a 2 e {M(CO)4} fragment (M=Mo or W) resulted in simple adducts, [{(Cp*Ta)(CH2S2)}2(B2H5)(H){M(CO)3}] (6: M=Mo and 7: M=W), that retained the diborane(5) unit. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Stabilization of Classical [B2H5]−: Structure and Bonding of [(Cp*Ta)2(B2H5)(μ-H)L2] (Cp*=η5-C5Me5; L=SCH2S)

Diborane(4) and diborane(6) molecules are demanding renewed interest due to their varied reactivity towards diverse substrates. The chemistry of molecules comprising electron-precise B-B bonds has witnessed swift developments in the recent years. In spite of the continuous interest and extensive efforts in the synthesis of diborane compounds, the formation of boron-boron bonds is still difficult and uncontrolled. On the other hand, the diborene molecules (R-B[dbnd]B-R′; R, R′ = H, phosphine, amine, NHC etc), are also of significant interest owing to their ability to regulate the property of biradicals by changing the substituents of the parent diborene(2), HB[dbnd]BH. In addition, transition metal diborene species exhibit fascinating photo-physical properties. In this review, we have delivered a background of B-B bond formation and a synopsis of the latest developments in the synthesis of boron-boron single and multiple bonds. The reactivity of diborane/diborene complexes towards various transition metals has also been discussed in detail. © 2019 Elsevier B.V.

Coordination Chemistry Reviews

Recent advances in transition metal diborane(6), diborane(4) and diborene(2) chemistry

The complexes [Ag{κ 3 -S,S′,H-H 2 B(mbz) 2 }(PR 3 )] x , (1: x = 2, R = Ph; 2: x = 1, R = Cy) (mbz = 2-mercaptobenzothiazolyl) and amidine based dihydro(2-mercaptobenzo-thiazolyl) borates, [HN=C(Ph)–NH(R)–H 2 B(mbz)] (3: R = 2,6-diisopropylphenyl and 4: R = Ph) were synthesized and characterized by various spectroscopic methods and single-crystal X-ray crystallography. Complex [Ag{κ 3 -S,S′,H-H 2 B(mbz) 2 }(PPh 3 )] 2 (1) has a dimeric structure in its crystalline state, in which central silver(I) atoms adopt a distorted trigonal bipyramid arrangement. In contrast, complex [Ag{κ 3 -S,S′,H-H 2 B(mbz) 2 }(PCy 3 )] (2) has a monomeric structure in its crystalline state, in which the central silver(I) atoms adopt a distorted trigonal planar arrangement. Infrared spectroscopy was utilized as a tool for investigating the presence of M···H–B interactions. In addition, density functional theory (DFT) calculations were used to analyse the B–H···[M] bonding interaction in the metal borate complexes. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Zeitschrift fur Anorganische und Allgemeine Chemie

Synthesis, Structural Characterization, and Theoretical Studies of Silver(I) Complexes of Dihydrobis(2-mercapto-benzothiazolyl) Borate

Room temperature photolysis of [(Cp*RuCO)2BH4(Bcat)], 3, generated from the reaction of arachno-[(Cp*RuCO)2B2H6], 1, with HBcat (cat = 1,2-O2C6H4), yielded a rare homodinuclear bridged-boryl complex, [(Cp*Ru)2(μ-H)(μ-CO)(μ-Bcat)], 4, confirmed by X-ray diffraction. © 2013 The Royal Society of Chemistry.

Journal of the Chemical Society. Dalton Transactions

A fine tuning of metallaborane to bridged-boryl complex, [(Cp*Ru)2(μ-H)(μ-CO)(μ-Bcat)] (cat = 1,2-O2C6H4; Cp* = η5-C5Me5)

A neutral metallaborane comprising a Rh4B12 polyhedron with icosioctahedron geometry with 16 vertices and 28 triangular faces was prepared (see structure; Rh: red, B: green). The cage has the shape of a 12-membered truncated tetrahedron with four capped hexagonal faces. © 2013 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

Boron beyond the icosahedral barrier: A 16-vertex metallaborane

Reaction of [1,2-(Cp*RuH)2B3H 7](1;Cp* = η-C5Me5) with [Mo(CO) 3(CH3CN)3] yielded arachno-[(Cp*RuCO) 2B2H6](2), which exhibits a butterfly structure, reminiscent of 7 sep B4H10. Compound 2 was found to be a very good precursor for the generation of bridged borylene species. Mild pyrolysis of 2 with [Fe2(CO)9] yielded a triply bridged heterotrinuclear borylene complex [(μ3-BH) (Cp*RuCO)2(μ-CO){Fe(CO)3}] (3) and bis-borylene complexes [{(μ3-BH)-(Cp*Ru)(μ-CO)}2Fe 2(CO)5](4) and [{(μ3-BH)(Cp*Ru)Fe(CO) 3}2(μ-CO)] (5). In a similar fashion, pyrolysis of 2 with [Mn2(CO)10] permits the isolation of μ3-borylene complex [(μ3-BH)-(Cp*RuCO) 2(μ-H)(μ-CO){Mn(CO)3}] (6) . Both compounds 3 and 6 have a trigonal-pyramidal geometry with the μ3-BH ligand occupying the apical vertex, whereas 4 and 5 can be viewed as bicapped tetrahedra, with two μ3-borylene ligands occupying the capping position. The synthesis of tantalum borylene complex [(μ3-BH)(Cp*TaCO) 2(μ-CO){Fe(CO)3}] (7) was achieved by the reaction of [(Cp*Ta)2B4H8(μ-BH4)] at ambient temperature with [Fe2(CO)9]. Compounds 2-7 have been isolated in modest yield as yellow to red crystalline solids. All the new compounds have been characterized in solution by mass spectrometry; IR spectroscopy; and 1H, 11B, and 13C NMR spectroscopy and the structural types were unequivocally established by crystallographic analysis of 2-6. © 2010 Wiley-VCH Verlag GmbH &amp; Co. KGaA.

Journal	Angewandte Chemie - International Edition
ISSN	14337851
Open Access	No