The chemistry of ruthenium–borane complex, [Cp∗RuCO(μ-H)BH2L] (Cp∗ = η5-C5Me5; L = C7H4NS2), 1 with various alkynes has been explored. Photolysis of 1 with alkynyl-Grignard, [HC[tbnd]CMgBr] in toluene led to the isolation of vinyl hydroborate complex [Cp∗Ru(μ-H)BH{HC[dbnd]CH2}L], 2a as a sole product. Compound 2a can be viewed as a ruthenium–borate complex with an ethylene moiety. Further, the chemistry of 1 with various internal and terminal alkynes has been performed in photolytic conditions. Photolysis of 1 with [RC[tbnd]CR] (R = CO2Me) yielded vinyl hydroborate complex [Cp∗Ru(μ-H)BCl{RC[dbnd]CR}L], 2b. Terminal alkynes [HC[tbnd]CR] (R = Ph or CO2Me) under the same reaction conditions led to the isolation of metal vinyl complexes [Cp∗Ru(CO)(C2HR)(L)], 3a and 3b (3a: R = Ph; 3b: R = CO2Me). In addition, DFT calculations were carried out to analyze the bonding and electronic structures of these new compounds. © 2017 Elsevier Ltd

Sundargopal Ghosh

Department Of Chemistry

Koushik Saha

Benson Joseph

Rosmita Borthakur

Rongala Ramalakshmi

Fulltext

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Polyhedron

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

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)

Chemistry of ruthenium σ-borane complex, [Cp∗RuCO(μ-H)BH2L] (Cp∗ = η5-C5Me5; L = C7H4NS2) with terminal and internal alkynes: Structural characterization of vinyl hydroborate and vinyl complexes of ruthenium

Thermolysis of [CpF∗Ru(PPh2(CH2)PPh2)BH2(L2)] 1 (Cp∗=η5-C5Me5; L=C7H4NS2), with terminal alkynes led to the formation of η4-σ,π-borataallyl complexes [Cp∗Ru(μ-H)B{R-C=CH2}(L)2] (2 a-c) and η2-vinylborane complexes [Cp∗Ru(R-C=CH2)BH(L)2] (3 a-c) (2 a, 3 a: R=Ph; 2 b, 3 b: R=COOCH3; 2 c, 3 c: R=p-CH3-C6H4; L=C7H4NS2) through hydroboration reaction. Ruthenium and the HBCC unit of the vinylborane moiety in 2 a-c are linked by a unique η4-interaction. Conversions of 1 into 3 a-c proceed through the formation of intermediates 2 a-c. Furthermore, in an attempt to expand the library of these novel complexes, chemistry of σ-borane complex [Cp∗RuCO(μ-H)BH2L] 4 (L=C7H4NS2) was investigated with both internal and terminal alkynes. Interestingly, under photolytic conditions, 4 reacts with methyl propiolate to generate the η4-σ,π-borataallyl complexes [Cp∗Ru(μ-H)BH{R-C=CH2}(L)] 5 and [Cp∗Ru(μ-H)BH{HC=CH-R}(L)] 6 (R=COOCH3; L=C7H4NS2) by Markovnikov and anti-Markovnikov hydroboration. In an extension, photolysis of 4 in the presence of dimethyl acetylenedicarboxylate yielded η4-σ,π-borataallyl complex [Cp∗Ru(μ-H)BH{R-C=CH-R}(L)] 7 (R=COOCH3; L=C7H4NS2). An agostic interaction was also found to be present in 2 a-c and 5-7, which is rare among the borataallyl complexes. All the new compounds have been characterized in solution by IR, 1H, 11B, 13C NMR spectroscopy, mass spectrometry and the structural types were unequivocally established by crystallographic analysis of 2 b, 3 a-c and 5-7. DFT calculations were performed to evaluate possible bonding and electronic structures of the new compounds. Building bridges: Hydroboration of σ-borane complexes with alkynes form novel η4-σ,π-borataallyl complexes (see figure). An agostic interaction was also found to be present, which is rare among the borataallyl complexes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemistry - A European Journal

η4-HBCC-σ,π-Borataallyl Complexes of Ruthenium Comprising an Agostic Interaction

Chloro-rhodaboratrane [(Cp∗Rh)(L2)BCl] 4 has been synthesized from rhodium N,S-heterocyclic carbene complex [(Cp∗Rh)(L2)(1-benzothiazol-2-ylidene)], 1, (L = C7H4NS2) and borane reagent BHCl2.SMe2. The Rh-B bond in 4 is buttressed between two benzothiazolyl units in [3.3.0] fashion. The presence of B-Cl bond allowed us to explore the chemistry of boratrane 4 at the boron centre. The reaction of ethynylmagnesium bromide with 4 yielded η1-vinyl complex [Cp∗RhBr(C2H2)L] 5, containing a five membered metallaheterocycle. In an objective to abstract the chloride, alike borylene synthesis from haloboryl, we performed the reaction of 4 with NaBArF4 that resulted the thiolato bridged bimetallic compound [Cp∗Rh(μ-L)3RhCp∗][BArF4] 6 (ArF: C6H3(CF3)2-3,5). © 2016 Elsevier B.V. All rights reserved.

Journal of Organometallic Chemistry

Chemistry of Rh-N,S heterocyclic carbene complexes

Building upon previous studies on the synthesis of bis(sigma)borate and agostic complexes of ruthenium, the chemistry of nido-[(Cp Ru)<inf>2</inf>B<inf>3</inf>H<inf>9</inf>] (1) with other ligand systems was explored. In this regard, mild thermolysis of nido-1 with 2-mercaptobenzothiazole (2-mbzt), 2-mercaptobenzoxazole (2-mbzo) and 2-mercaptobenzimidazole (2-mbzi) ligands were performed which led to the isolation of bis(sigma)borate complexes [Cp RuBH<inf>3</inf>L] (2a-c) and β-agostic complexes [Cp RuBH<inf>2</inf>L<inf>2</inf>] (3a-c; 2a, 3a: L=C<inf>7</inf>H<inf>4</inf>NS<inf>2</inf>; 2b, 3b: L=C<inf>7</inf>H<inf>4</inf>NSO; 2c, 3c: L=C<inf>7</inf>H<inf>5</inf>N<inf>2</inf>S). Further, the chemistry of these novel complexes towards various diphosphine ligands was investigated. Room temperature treatment of 3a with [PPh<inf>2</inf>(CH<inf>2</inf>)<inf>n</inf>PPh<inf>2</inf>] (n=1-3) yielded [Cp Ru(PPh<inf>2</inf>(CH<inf>2</inf>)<inf>n</inf>PPh<inf>2</inf>)-BH<inf>2</inf>(L<inf>2</inf>)] (4a-c; 4a: n=1; 4b: n=2; 4c: n=3; L=C<inf>7</inf>H<inf>4</inf>NS<inf>2</inf>). Mild thermolysis of 2a with [PPh<inf>2</inf>(CH<inf>2</inf>)<inf>n</inf>PPh<inf>2</inf>] (n=1-3) led to the isolation of [Cp Ru(PPh<inf>2</inf>(CH<inf>2</inf>)<inf>n</inf>PPh<inf>2</inf>)(L)] (L=C<inf>7</inf>H<inf>4</inf>NS<inf>2</inf> 5a-c; 5a: n=1; 5b: n=2; 5c: n=3). Treatment of 4a with terminal alkynes causes a hydroboration reaction to generate vinylborane complexes [Cp Ru(R-C=CH<inf>2</inf>)BH(L<inf>2</inf>)] (6 and 7; 6: R=Ph; 7: R=COOCH<inf>3</inf>; L=C<inf>7</inf>H<inf>4</inf>NS<inf>2</inf>). Complexes 6 and 7 can also be viewed as η-alkene complexes of ruthenium that feature a dative bond to the ruthenium centre from the vinylinic double bond. In addition, DFT computations were performed to shed light on the bonding and electronic structures of the new compounds. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydroboration of Alkynes with Zwitterionic Ruthenium-Borate Complexes: Novel Vinylborane Complexes

Building upon our earlier results on the chemistry of diruthenium analogue of pentaborane (9) with heterocumulenes, we continued to investigate the reactivity of arachno-[(Cp∗Ru)<inf>2</inf>(B<inf>3</inf>H<inf>8</inf>)(CS<inf>2</inf>H)], 1, (Cp∗ = η5-C<inf>5</inf>Me<inf>5</inf>) towards group 7 and 8 transition metal carbonyl compounds under photolytic and thermolytic conditions. The metal carbonyl compounds show diverse reactivity pattern with arachno-1. For example, the photolysis of arachno-1 with [Re<inf>2</inf>(CO)<inf>10</inf>] yielded [(Cp∗Ru)<inf>2</inf>B<inf>3</inf>H<inf>5</inf>(CH<inf>2</inf>S<inf>2</inf>){Re(CO)<inf>4</inf>}<inf>2</inf>], 2, [(Cp∗RuCO)<inf>2</inf>(μ-H)<inf>2</inf>(CH<inf>2</inf>S<inf>2</inf>){Re(CO)<inf>4</inf>}{Re(CO)<inf>3</inf>}], 3 and [(Cp∗Ru)<inf>2</inf>(μ-CO)(μ-H)(CH<inf>2</inf>S<inf>2</inf>){Re(CO)<inf>3</inf>}], 4. The geometry of 2 with a nearly planar eight-membered ring containing heavier transition metals rhenium, ruthenium is unprecedented. Compounds 3 and 4 can be considered as M<inf>4</inf>-quadrilateral and M<inf>3</inf>-triangle with a methylenedithiolato ligand attached to the metal centres, respectively. [Mn<inf>2</inf>(CO)<inf>10</inf>], on the other hand, reacts with arachno-1 to yield heterometallic binuclear [(Cp∗RuCO){Mn(CO)<inf>4</inf>}(μ-H)(SCH<inf>3</inf>)], 5 and homocubane [(Cp∗Ru)<inf>2</inf>{Mn(CO)<inf>3</inf>}-(CS<inf>2</inf>H<inf>2</inf>)B<inf>3</inf>H<inf>4</inf>], 6. In an attempt to generate group 8 analogues of 2-5, we performed the reaction of arachno-1 with [Fe<inf>2</inf>(CO)<inf>9</inf>] and [Ru<inf>3</inf>(CO)<inf>12</inf>]. Although, the objective of isolating analogous compounds was not achieved, the reaction with [Fe<inf>2</inf>(CO)<inf>9</inf>] led to novel tetrahedral cluster [(Cp∗RuCO){(Fe(CO)<inf>3</inf>}<inf>2</inf>S(μ-H)], 7. [Ru<inf>3</inf>(CO)<inf>12</inf>], in contrast, yielded known compounds [{Cp∗Ru(CO)}<inf>2</inf>B<inf>2</inf>H<inf>6</inf>], 9 and [Cp∗Ru(CO)<inf>2</inf>]<inf>2</inf>, 10. All the cluster compounds have been characterized by mass spectrometry, IR, and 1H, 11B, and 13C NMR spectroscopy, and the geometric structures were unequivocally established by crystallographic analysis of 2-5 and 7. © The Royal Society of Chemistry.

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Publisher	Data powered by TypesetElsevier Ltd
ISSN	02775387
Open Access	Yes