Building upon our earlier results on the synthesis of electron-precise transition-metal-boron complexes, we continue to investigate the reactivity of pentaborane(9) and tetraborane(10) analogues of ruthenium and rhodium towards thiazolyl and oxazolyl ligands. Thus, mild thermolysis of nido-[(Cp*RuH)2B3H7] (1) with 2-mercaptobenzothiazole (2-mbtz) and 2-mercaptobenzoxazole (2-mboz) led to the isolation of Cp*-based (Cp* = η(5)-C5Me5) borate complexes 5 a,b [Cp*RuBH3L] (5 a: L = C7H4NS2; 5 b: L = C7H4NOS)) and agostic complexes 7 a,b [Cp*RuBH2(L)2], (7 a: L = C7H4NS2; 7 b: L = C7H4NOS). In a similar fashion, a rhodium analogue of pentaborane(9), nido-[(Cp*Rh)2B3H7] (2) yielded rhodaboratrane [Cp*RhBH(L)2], 10 (L = C7H4NS2). Interestingly, when the reaction was performed with an excess of 2-mbtz, it led to the formation of the first structurally characterized N,S-heterocyclic rhodium-carbene complex [(Cp*Rh)(L2)(1-benzothiazol-2-ylidene)] (11) (L = C7H4NS2). Furthermore, to evaluate the scope of this new route, we extended this chemistry towards the diruthenium analogue of tetraborane(10), arachno-[(Cp*RuCO)2B2H6] (3), in which the metal center possesses different ancillary ligands.
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http://dx.doi.org/10.1002/chem.201405218 | DOI Listing |
Dalton Trans
January 2025
Department of Chemistry, Graduate School of Natural Science and Technology, Shimane University, 1060, Nishikawatsu, Matsue, Shimane, 690-8504, Japan.
Paddlewheel-type diruthenium(II,II) complexes are paramagnetic with two unpaired electrons ( = 1) and can be utilized as versatile building blocks for higher-order structures, such as supramolecular complexes, coordination polymers, and metal-organic frameworks, although they are generally highly air-sensitive. In this study, we developed an air-stable paddlewheel-type diruthenium(II,II) complex with two electron-withdrawing 1,8-naphthyridine-2-carboxylate (npc) ligands, [Ru(μ-npc)(OCMe)] (1). The two acetate ligands in 1 can be replaced by other carboxylate ligands; the solvothermal reactions of 1 with benzoic acid (HOCPh) yields the heteroleptic [Ru(μ-npc)(OCPh)] (2), whereas its reaction with 1,8-naphthyridine-2-carboxylic acid (Hnpc) produces the homoleptic [Ru(μ-npc)(η-npc)] (3).
View Article and Find Full Text PDFDalton Trans
January 2025
Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
Benzoate-bridged paddlewheel diruthenium(II,II) complexes ([RuII,II2(RArCO)(L)] (L = axial ligand); [RuII,II2]) exhibit reversible redox activity involving the oxidized species [RuII,III2]. The redox activity can be finely tuned over a broad potential range by altering the substituent R on the benzoate-bridging ligand RArCO. The electronic contributions of the substituents R depend on their type and position, as was empirically demonstrated by Hammett for substituents at the - and -positions.
View Article and Find Full Text PDFDalton Trans
January 2025
Dipartimento di Farmacia, Università degli Studi "G. D'Annunzio" Chieti-Pescara, Via dei Vestini 31, 66100 Chieti, Italy.
Paddlewheel complexes of bimetallic scaffolds are emerging metallic agents in the bioinorganic chemistry landscape. In the most commonly employed construct, these complexes are decorated by the carboxylate moiety, prompting their possible deployment to target either protein or nucleic acid targets. In this study, density functional investigation was performed to assess viable mechanistic routes for the substitution of one acetate ligand with one chelating purine, adenine or guanine, in diruthenium and dirhodium tetraacetate paddlewheel complexes.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Department of Chemical Sciences, University of Naples Federico II, Complesso Univ. di Monte Sant'Angelo, via Cinthia, 26, 80126 Naples, Italy. Electronic address:
The charge of paddlewheel diruthenium complexes has a major role in defining their interaction with proteins: negatively charged complexes bind proteins non-covalently, while cationic complexes form adducts where the Ru core binds to Asp side chains at the equatorial sites, or to the main chain carbonyl groups or the side chains of His, Arg or Lys residues at the axial sites. Here we study the interactions of the neutral compound [Ru(D-p-FPhF)(OCCH)(OCO)]·3HO (D-p-FPhF = N,N'-bis(4-fluorophenyl)formamidinate), a very rare example of a paddlewheel diruthenium compound with three different equatorial ligands, with the model protein bovine pancreatic ribonuclease (RNase A) by means of UV-visible absorption spectroscopy, circular dichroism (CD), electrospray ionization mass spectrometry (ESI-MS) and X-ray crystallography. It is the first attempt to investigate the binding of a neutral diruthenium compound to a protein.
View Article and Find Full Text PDFInorg Chem
November 2024
Department of Chemistry, University of Wroclaw, ul. Joliot-Curie 14, 50-383 Wroclaw, Poland.
The large expanded telluraporphyrin, tetratellura[36]octaphyrin(1.1.1.
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