Protonation of (N-N)PtPh(2) (1; N-N = diimine ArN=CMe-CMe=NAr with Ar = 2,6-Me(2)C(6)H(3) (a), 2,4,6-Me(3)C(6)H(2) (b), 4-Br-2,6-Me(2)C(6)H(2) (c), 3,5-Me(2)C(6)H(3) (d), and 4-CF(3)C(6)H(4) (e)) in the presence of MeCN at ambient temperature generates (N-N)Pt(Ph)(NCMe)(+) (2). At -78 degrees C, protonation of 1a yielded (N-N)PtPh(2)(H)(NCMe)(+) (3a), which produced benzene and 2a at ca. -40 degrees C. Protonation of 1a-e in CD(2)Cl(2)/Et(2)O-d(10) furnished (N-N)Pt(C(6)H(5))(eta(2)-C(6)H(6))(+) (4a-e). The pi-benzene complexes 4a-c, sterically protected at Pt, eliminate benzene at ca. 0 degree C. The sterically less protected 4d-e lose benzene already at -30 degrees C. SST and 2D EXSY NMR demonstrate that phenyl and pi-benzene ligand protons undergo exchange with concomitant symmetrization of the diimine ligand, most likely via oxidative insertion of Pt into a C-H bond of coordinated benzene. The kinetics of the exchange processes for 4a-c were probed by quantitative EXSY spectroscopy, resulting in DeltaH() of 70-72 kJ mol(-1) and DeltaS of 37-48 J K(-1) mol(-1). A large, strongly temperature-dependent H/D kinetic isotope effect (9.7 at -34 degrees C; 6.9 at -19 degrees C) was measured for the dynamic behavior of 4a versus 4a-d(10), consistent with the proposed pi-benzene C-H bond cleavage. The fact that the pi-benzene complex 4a is thermally more robust in the absence of MeCN than is the Pt(IV) hydridodiphenyl complex 3a in the presence of MeCN agrees with the notion that arene elimination from Pt(IV) hydridoaryl complexes occurs via Pt(II) pi-arene intermediates that eliminate the hydrocarbon associatively, in this case, promoted by MeCN. Compounds 1a, 1b, 1d, 2a, and 2b have been crystallographically characterized.
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Dalton Trans
January 2025
LCC-CNRS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, BP44099 F-31077 Toulouse cedex 4, France.
Functional pincer ligands that engage in metal-ligand cooperativity and/or are capable of redox non-innocence have found a great deal of success in catalysis. These two properties may be found in metal complexes of the 2,6-bis(pyrazol-3-yl)pyridine (bpp) ligands. With this goal in mind, we have attempted the coordination of 2,6-bis(5-trifluoromethylpyrazol-3-yl)pyridine (LCF3) and its Bu analogue 2,6-bis(5--butylpyrazol-3-yl)pyridine (LtBu) to Mo(0) by reactions with mixed phosphine/carbonyl complexes [Mo(CO)(MeCN)(PMePh)] 1-3 (1 ≤ ≤ 3).
View Article and Find Full Text PDFACS Org Inorg Au
December 2024
Department of Chemistry, Vanderbilt University, PO Box 1822 Nashville, Tennessee 37235, United States.
Metal complexes with -Bu-substituted allyl ligands are relatively rare, especially compared to their conceptually similar trimethylsilyl-substituted analogs. The scarcity partially stems from the few general synthetic entry points for the -Bu versions. This situation was studied through a modified synthesis for the allyl ligand itself and by forming several mono(allyl)nickel derivatives.
View Article and Find Full Text PDFJ Colloid Interface Sci
February 2025
State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China; University of Science and Technology of China, Hefei, Anhui 230026, China. Electronic address:
Nanozymes, as promising alternatives to natural enzymes, offer several advantages with biocatalytic functions but remain inferior in catalytic activity. It is crucial to focus on factors that affect the enzymatic activity of nanozymes and develop strategies to make them more competitive with natural enzymes. Herein, CuVO nanorods are confirmed to own the intrinsic laccase-like activity, and an acetonitrile (MeCN)-mediated strategy is proposed for reaction acceleration by mimicking the enzymatic substrate pocket.
View Article and Find Full Text PDFDalton Trans
November 2024
Institute of Chemistry, Faculty of Science and Technology, University of Silesia, Szkolna 9, 40-006 Katowice, Poland.
This is a comprehensive study of the photophysical behaviour of heteroleptic iridium(III) complexes with imidazo[4,5-][1,10]phenanthroline (imphen) as an ancillary ligand, represented by the general formula [Ir(N∩C)(imphen)]PF. As cyclometalating ligands, 2-phenylpyridine (Hppy), 2-phenylquinoline (Hpquin), 2-phenylbenzothiazole (Hpbztz), and 2-(2-pyridyl)benzothiophene (pybzthH) were used. The impact of structural modifications of cyclometalating ligands was widely explored by a combination of steady-state and time-resolved optical techniques accompanied by theoretical calculations.
View Article and Find Full Text PDFMolecules
September 2024
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, University of Chinese Academy of Sciences, Fuzhou 350002, China.
Tetrahedral copper(I) clusters [Cu(MBIZ)(PPh)] (), [Cu(MBOZ)(PPh)] () (MBIZ = 2-mercaptobenzimidazole, MBOZ = 2-mercaptobenzoxazole) were prepared by regulation of the copper-thiolate clusters [Cu(MBIZ)] () and [Cu(MBOZ)I] () with PPh. With the presence of iodide anion, the regulation provided the iodide-containing clusters [Cu(MBIZ)(PPh)I] () and [Cu(MBOZ)(PPh)I] (). The cyclic voltammogram of in MeCN (0.
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