Synthesis and Characterization of the Series of Compounds Ru₂(O₂CMe)_x(admp)_4-xCl (Hadmp = 2-Amino-4,6-dimethylpyridine, x = 3, 2, 1, 0)

Abstract

The reaction between Ru(2)(O(2)CMe)(4)Cl and Hadmp (Hadmp = 2-amino-4,6-dimethylpyridine) under different conditions has been investigated. By conducting the reaction in a methanol solution at room temperature the product obtained was Ru(2)(admp)(O(2)CMe)(3)Cl (1). In a melt reaction at 65 degrees C the product isolated is Ru(2)(admp)(2)(O(2)CMe)(2)Cl (2); at 100 degrees C it is Ru(2)(admp)(3)(O(2)CMe)Cl (3); and at 140 degrees C it is Ru(2)(admp)(4)Cl (4). The generality of these reactions was confirmed by the deliberate preparation of Ru(2)(chp)(3)(O(2)CMe)Cl (5) and [Ru(2)(DPhTA)(3)(O(2)CMe)(NCMe)(2)][BF(4)] (6). The structures of 1, 2, and 3 were determined by X-ray crystallography. The structure of 1 was determined from crystals of 1.3CH(2)Cl(2) (C(16)H(24)Cl(7)N(2)O(6)Ru(2)), triclinic, P&onemacr; (No. 2), with a = 11.578(3) Å, b = 12.5607(13) Å, c = 20.903(3) Å, alpha = 99.927(14) degrees, beta = 100.222(9) degrees, gamma = 102.07(2) degrees, Z = 4; that of 2, from crystals of 2.2.5CH(2)Cl(2) (C(21)H(30)Cl(7)N(4)O(4)Ru(2)), monoclinic, P2(1)/n (No. 14), with a = 13.091(3) Å, b = 19.098(4) Å, c = 13.720(3) Å, beta = 105.51(3) degrees; that of 3, from crystals of 3.Hadmp.C(6)H(6) (C(36)H(46)ClN(8)O(2)Ru(2)), monoclinic, P2(1)/n (No. 14), with a = 15.979(2) Å, b = 14.9294(14) Å, c = 17.131(4) Å, beta = 109.21(2) degrees. The magnetic susceptibilities and electrochemistry of the four title compounds were also studied. It was observed that while compounds 1, 2, and 3 display magnetic moments compatible with the presence of three unpaired electrons and all yield stable one-electron oxidation products, 4 shows only one unpaired electron and the product of its one-electron oxidation decays sufficiently rapidly that no return wave is observed.

Tuning the Magnetic Moment of [Ru2(DPhF)3(O2CMe)L]+ Complexes (DPhF=N,N′‐Diphenylformamidinate): A Theoretical Explanation of the Axial Ligand Influence

“…However, the substitution of the axial chloride by a NCS À ligand leads to the [25] which indicates a p* 3 or d* 2 p* electronic configuration. Similar low-spin magnetic behaviour was observed [25][26][27] in the Ru 2 4 Cl] [28] [29] a physical mixture of spins, for example, [{Ru 2 [30] or systems with quantum admixture of spins, for example, […”

Ruthenium Compounds

“…By careful control of the experimental conditions of these reactions complexes with a mixed set of aminopyridinate/acetate ligands can be selectively synthesized. 97,108 For example, by reacting Ru 2 (O 2 CMe) 4 Cl with excess of Hadmp in MeOH at room temperature the mono-substituted complex is obtained, while a second admp ligand is introduced when the reaction takes place in boiling THF; further substitution is carried out at higher temperatures using molten Hadmp.…”

“…116,117 Complexes with a mixed set of bridging ligands of the type Ru 2 (O 2 CMe) 4-x (admp) x Cl (x = 1, 2, 3) exhibit two redox processes, a one-electron oxidation which becomes easier as the number of aminopyridinate ligands increases, and an one-electron reduction of increasing diffi culty with the number of aminopyridinate ligands. 108 However, the analogous mixed-ligand Ru 2 5+ complex Ru 2 (O 2 CMe)(HNC 5 H 3 NMe) 3 Cl shows three metal-based redox processes, which have been assigned to the oxidation of the Ru 2 5+ core to Ru 2 6+ and the reductions to Ru 2 4+ and further to a rare Ru 2 3+ species. 123 As shown in Table 9.1, the Ru-Ru bond lengths in Ru 2 5+ aminopyridinates fall in the range of 2.274 to 2.336 Å (Ru 2 (2-Fap) 4 Cl(NO) is an exception; see below).…”

“…However, the magnetic moment of Ru 2 (admp) 4 Cl implies the presence of only one unpaired electron. 108 The explanation that was given is that the four admp ligands cause a destabilization of the * orbital resulting in the 2 4 2 * 3 electronic confi guration.…”

Synthesis, structure, and electrochemical characterization of a mixed-ligand diruthenium(iii,ii) complex with an unusual arrangement of the bridging ligands

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] The compounds which have been investigated in most detail are represented as [Ru 2 L 4 ] n+ and [Ru 2 (L) x (L′) 4−x ] n+ , where x = 1, 2 or 3, n = 0 or +1, L is a symmetrical or unsymmetrical anionic bridging ligand and L′ is usually an acetate ligand. 2,[19][20][21][22][23][24][25][26][27] The totally substituted diruthenium complexes with unsymmetrical bridging ligands can exist in up to four different isomeric forms that have been labeled as having (4,0), (3,1), (2,2)-cis and (2,2)-trans conformations 9,13,[28][29][30] but generally only one or two isomers have been isolated in a given synthesis. For example, in the case of substituted ap ligands (ap = 2-anilinopyridinate anion), Ru 2 (2,6-F 2 ap) 4 Cl and Ru 2 (2,4,6-F 3 ap) 4 Cl were isolated as a mixture of (3,1) and (4,0) isomers, 13 while Ru 2 (2-Fap) 4 Cl exists exclusively in its (3,1) isomeric form 13 and Ru 2 (2-CH 3 ap) 4 Cl is obtained only as the (4,0) isomer.…”