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.

Thermolysis of [Cp*Ru(PPh2 (CH2 )PPh2 )BH2 (L2 )] 1 (Cp*=η(5) -C5 Me5 ; L=C7 H4 NS2 ), with terminal alkynes led to the formation of η(4) -σ,π-borataallyl complexes [Cp*Ru(μ-H)B{R-C=CH2 }(L)2 ] (2 a-c) and η(2) -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 -C6 H4 ; L=C7 H4 NS2 ) through hydroboration reaction. Ruthenium and the HBCC unit of the vinylborane moiety in 2 a-c are linked by a unique η(4) -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)BH2 L] 4 (L=C7 H4 NS2 ) was investigated with both internal and terminal alkynes. Interestingly, under photolytic conditions, 4 reacts with methyl propiolate to generate the η(4) -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=C7 H4 NS2 ) by Markovnikov and anti-Markovnikov hydroboration. In an extension, photolysis of 4 in the presence of dimethyl acetylenedicarboxylate yielded η(4) -σ,π-borataallyl complex [Cp*Ru(μ-H)BH{R-C=CH-R}(L)] 7 (R=COOCH3 ; L=C7 H4 NS2 ). 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, (1) H, (11) B, (13) C 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.

The chemistry of ruthenium-borane complex, [Cp*RuCO(µ-H)BH 2 L] (Cp* = η 5-C 5 Me 5 ; L = C 7 H 4 NS 2), 1 with various alkynes has been explored. Photolysis of 1 with alkynyl-Grignard, [HC≡CMgBr] in toluene led to the isolation of vinyl hydroborate complex [Cp*Ru(µ-H)BH{HC=CH 2 }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≡CR] (R = CO 2 Me) yielded vinyl hydroborate complex [Cp*Ru(µ-H)BCl{RC=CR}L], 2b. Terminal alkynes [HC≡CR] (R = Ph or CO 2 Me) under the same reaction conditions led to the isolation of metal vinyl complexes [Cp*Ru(CO)(C 2 HR)(L)], 3a and 3b (3a: R = Ph; 3b: R = CO 2 Me). In addition, DFT calculations were carried out to analyze the bonding and electronic structures of these new compounds.

Building upon our earlier studies of cobaltaheteroboranes, we explore the chemistry with heavier group 9 metals. Reaction of [Cp*M(μ-Cl)Cl x ] 2 (Cp* = η 5 -C 5 Me 5 ; M = Co, x = 0; M = Rh or Ir, x = 1) with [LiBH 4 ·THF], followed by thermolysis with an excess of chalcogen powders (S or Se), affords dimetallaheteroboranes nido-[(Cp*M) 2 B 2 H 2 E 2 ], 1-4 (1: E = S; 2: E = Se, M = Co; 3 and 4: E = Se, M = Rh and Ir, respectively) in moderate-to-good yields. The solid-state structures of these compounds show open-cage triple-decker clusters. Attempts to isolate the Te analogue have failed; however, in the case of cobalt, we have isolated an 11 skeletal-electron-pair nido-[(Cp*Co) 2 B 5 H 5 Te 2 ], 5. The X-ray diffraction structure of 5 shows monocapped square antiprismatic geometry, with two Te atoms in the core. To close the central four-membered B 2 E 2 open ring [a]

In an effort to generate triple-decker complexes comprising a {PdCl 2 }moiety in the middle deck, we have explored the reactivity of [(Cp*M) 2 {μ-B 2 H 2 E 2 }], 1−4 (1: M = Co, E = S; 2: M = Co, E = Se; 3: M = Rh, E = Se; and 4: M = Ir, E = Se; Cp* = η 5 -C 5 Me 5 ), with [PdCl 2 (COD)] (COD = 1,5-cyclooctadiene). The reactions led to the formation of a series of trinuclear heterometallic triple-decker complexes, [(Cp*M) 2 {μ-B 2 H 2 E 2 Pd-(Cl) 2 }], 5−8

No abstract

Herein, a new type of carbodicarbene (CDC) comprising two different classes of carbenes is reported; NHC and CAAC as donor substituents and compare the molecular structure and coordination to Au(I)Cl to those of NHC‐only and CAAC‐only analogues. The conjugate acids of these three CDCs exhibit notable redox properties. Their reactions with [NO][SbF6] were investigated. The reduction of the conjugate acid of CAAC‐only based CDC with KC8 results in the formation of hydrogen abstracted/eliminated products, which proceed through a neutral radical intermediate, detected by EPR spectroscopy. In contrast, the reduction of conjugate acids of NHC‐only and NHC/CAAC based CDCs led to intermolecular reductive (reversible) carbon–carbon sigma bond formation. The resulting relatively elongated carbon–carbon sigma bonds were found to be readily oxidized. They were, thus, demonstrated to be potent reducing agents, underlining their potential utility as organic electron donors and n‐dopants in organic semiconductor molecules.

Various bimetallic bis- and tris-homocubane analogues of group 9 transition metals have been isolated and structurally characterized employing Li[BH2E3] (E = S or Se).