RESUMO
Isolation of planar [B6 H6 ] is a long-awaited goal in boron chemistry. Several attempts in the past to stabilize [B6 H6 ] were unsuccessful due to the domination of polyhedral geometries. Herein, we report the synthesis of a triple-decker sandwich complex of titanium [(Cp*Ti)2 (µ-η6 : η6 -B6 H6 )(µ-H)6 ] (1), which features the first-ever experimentally achieved nearly planar six-membered [B6 H6 ] ring, albeit within a [B6 H12 ] borate. The small deviation from planarity is a direct consequence of the predicted structural pattern of the middle ring in 24 Valence Electron Count (VEC) triple-decker complexes. The large ring size of [B6 H6 ] in 1 brings the metal-metal distance into the bonding range. However, significant electron delocalization from the M-M bonding orbital to the bridging hydrogen and B-B skeleton in the middle decreases its bond strength.
RESUMO
A new class of bi-luminophoric dyad has been designed, consisting of an oxygen-sensitive phosphorescent NHC-IrIII center with a remotely integrated oxygen-insensitive fluorescent terpyridine unit. The new terpyridine flurophore-integrated NHC-IrIII molecule was demonstrated as a potential ratiometric O2 probe with built-in internal reference, exhibiting tunable dual-emissive features, as well as highly linear and reversible O2 -response behavior.
RESUMO
The chemistry of the Cp* based κ2-N,S-chelated ruthenium complex, [Cp*RuPPh3(κ2-N,S-(NC7H4S2)], 1 with different boranes has been explored. The room temperature reaction of 1 with BH3·THF and bulky boranes, such as MesBH2 and H2BArF, led to the formation of different dihydridoborate complexes, [{κ3-S,H,H-(NBH2R)(S2H4C7)}RuCp*], 2-4 (2: R = H, 3: R = Mes, and 4: R = ArF; Mes = 2,4,6-trimethylphenyl, and ArF = 3,5-bistrifluoromethyl-benzene). In contrast, the Cp* based κ2-N,S-chelated molybdenum complex, [Cp*Mo(CO)2{κ2-N,S-(NC7H4S2)}], 5, yielded the agostic borate species, [Cp*Mo(CO)2{κ2-S,H-(NBH2R) (NC7H4S2)}], 6 and 7 (6: R = Mes and 7: R = ArF) at elevated temperatures.
RESUMO
Thermolysis of [(Cp*Nb)2(B2H6)2], 1b (Cp* = η5-C5Me5), with 2-mercaptobenzothiazole, C6H4NSCSH (MBT), and 2-mercaptobenzoxazole, C6H4NOCSH (MBO), yielded hydrogen substituted compounds 2 and 3 with a general formula [(Cp*Nb)2(B2H6)(B2H5L)] (2: L = C6H4NSCS and 3: L = C6H4NOCS). A similar reaction of 1b with Ph2Se2 yielded the monosubstituted derivative [(Cp*Nb)2(B2H6){B2H5(PhSe)}], 4. All further efforts towards persubstitution of 1b under various drastic conditions were unfruitful. In parallel, in an effort to find a better synthetic route to the known Ta-aziridine complex [Cp*TaBH(C7H4NS2)CH2S2NC6H4], Cp*TaCl4 was treated with a 2-mercaptobenzothiazolyl-based borate ligand Na[H2B(C6H4NSCS)2]. Surprisingly, the reaction led to the formation of the half-sandwich trichloroaryltantalum(v) complex [Cp*TaCl3{κ2-N,S-C6H4NSCS}], 5, containing a heterocyclic thiol ligand. Using an alternative method complex 5 was isolated in good yield when Cp*TaCl4 was treated with the potassium salt of 2-mercaptobenzothiazole K[C6H4NSCS]. All the compounds were characterized by 1H, 11B{1H}, and 13C{1H} NMR spectroscopy, and their structures were unequivocally established by crystallographic analysis.
RESUMO
The reaction of [CH{(CMe)(2,6-iPr2C6H3N)}2]GeCl with LiN(SiMe3)2 was previously reported, which led to the formation of a hetero-fulvene type germylene, [CH{(CMe)(C[double bond, length as m-dash]CH2)(2,6-iPr2C6H3N)}2]Ge through the deprotonation of the C-H bond from the methyl substituents. In this paper, we attempted the analogous reaction with (Dipp)NCMeCHCOMeGeCl using LiN(SiMe3)2 which gave rise to a metathesis product, (Dipp)NCMeCHCOMeGeN(SiMe3)2 (2). However, the reactions of 2 with [M2Cl2(µ-Cl)2(η5-Cp*)2] (M = Rh and Ir) resulted in cyclometallated Rh and Ir complexes through the activation of the C-H bond from the germylene ligand. The complexes were characterized by single crystal X-ray analysis, which authenticated the presence of Ge-Rh and Ge-Ir bonds. DFT studies have been performed to understand the mechanism.