Low-melting salts with the [CrIII(NCS)4(1,10-phenanthroline)]− complex anion: Syntheses, properties, and structures

Abstract

Four new low melting salts, "Ionic Liquids" consisting of the [Cr III (NCS) 4 (Phen)] − complex monoanion and imidazolium based cations A, with A = 1 ethyl 3 methylimidazolium (EMIm), 1 butyl 3 methylimidazolium (BMIm), 1,3 dimethyl 2,4,5 triphenylimidazolium (DML), and 1,2,3,4,5 pentamethyl imidazolium (PMIm), were investigated. Single crystal X ray investigations established the structures of the four compounds. (EMIm)[Cr(NCS) 4 (Phen)] (I): triclinic, a = 8.1382(6), b = 10.4760(8), c = 16.003(1) Å, α = 90.330(4)°, β = 94.759(4)°, γ = 107.305(4)°, Z = 2, R 1 (F)/wR 2 (F 2 ) = 0.0650/0.1770; (BMIm)[Cr(NCS) 4 (Phen)] (II): triclinic, a = 8.5545(4), b = 9.8620(4), c = 16.6762(6) Å, α = 92.503(2)°, β = 97.517(2)°, γ = 91.249(2)°, Z = 2, R 1 (F)/wR 2 (F 2 ) = 0.0393/0.0848; (DML)[Cr(NCS) 4 (Phen)] ⋅ C 3 H 6 O (III): triclinic, a = 11.0475(9), b = 13.589(1), c = 14.582(1) Å, α = 83.013(4)°, β = 87.116(4)°, γ = 70.333(5)°, Z = 2, R 1 (F)/wR 2 (F 2 ) = 0.0407/0.1023; (PMIm)[Cr(NCS) 4 (Phen)] ⋅ C 3 H 6 O (IV): orthorhombic, Pbca, a = 17.379(1), b = 16.514 (1), c = 22.304(1) Å, Z = 8, R 1 (F)/wR 2 (F 2 ) = 0.0460/0.1107 (in addition III and IV contain co crystallized acetone molecules). Each compound was characterized by elemental analysis, NMR, IR, und UV⎯Vis spectroscopy. Magnetic properties were derived from NMR investigations (EVANS method). All four compounds are paramagnetic with effective magnetic moments of spin only Cr III . Melting points were obtained from DSC measurements. All melting points are higher than required for "Ionic Liquids", but nevertheless "low" for molten salts.

Towards ionic liquids with tailored magnetic properties: bmim+ salts of ferro- and antiferromagnetic CuII3 triangles

“…6 Interestingly, studies on paramagnetic MCILs predate those works, but were focused on other aspects of the materials, disregarding their magnetic properties. 7,8 Subsequent to these studies, the magnetic properties of MCILs started attracting more attention, with reports of MCILs containing mononuclear magnetic cations, [9][10][11][12][13][14][15][16] mononuclear magnetic anions [17][18][19][20][21][22][23][24][25] and one report on the magnetic properties of a triferric cationic MCIL. 26 Due to the mononuclear structures of the spin carriers in those magnetic MCILs, the tuning of their magnetic properties, when attempted, focused on modifications of the diamagnetic counterion; e.g., it was demonstrated that changing the countercation charge, two or three [FeCl 3 Br] anions could be assembled around it, yielding a higher magnetic moment per formula unit.…”

Identification and characterization of an imidazolium by‐product formed during the synthesis of 4‐methylmethcathinone (mephedrone)

“…3.6 Å. The characterization of the mephedrone by‐product added to the few structurally known tetramethylimidazolium‐R + X − compounds (R = Me, X = I; R = CH 2 I, X = I; R = Me, X = (SCN) 4 Crphenanthroline; R = Me, X = (SCN) 4 Cr(NH 3 ) 2 ; R = Me, X = N(SO 2 CF 3 ) 2 ) [22‐27] …”

“…The characterization of the mephedrone by-product added to the few structurally known tetramethylimidazolium-R + X À compounds (R = Me, X = I; R = CH 2 I, X = I; R = Me, X = (SCN) 4 Crphenanthroline; R = Me, X = (SCN) 4 Cr(NH 3 ) 2 ; R = Me, X = N(SO 2 CF 3 ) 2 ). [22][23][24][25][26][27] A mechanism of formation is proposed to account for the formation of TMMPI during mephedrone synthesis (Figure 3). The carbonyl group on mephedrone was thought to undergo a reduction to the alcohol followed by dimerization and subsequent loss of water.…”

New Low-Melting Triply Charged Homoleptic Cr(III)-Based Ionic Liquids in Comparison to Their Singly Charged Heteroleptic Analogues

“…Over the last decade, we have reported structural information on different series of low-melting imidazolium-based transition MILs. These include 3d metal-based complexes containing Co (e.g., (RIm) 2 [CoBr 4 ], R = 1-butyl-3-methylimidazolium, 1,3-dibutyl-2,4,5-trimethylimidazolium; (RMIm) 2 [Co(NCX) 4 ], R = methyl, ethyl, X = O, S; and (RMIm)[CoBr 3 quin], R = ethyl, n-butyl, n-hexyl, n-nonyl, quin = quinoline) [24][25][26][27], Ni (e.g., (RIm) 2 [NiBr 4 ], R = 1,3-dibutyl-2,4,5-trimethylimidazolium; and (RMIm)[NiBr 3 L], R = ethyl, L = N-methylimidazole, N-methylbenzimidazole, quinoline, PPh 3 ) [27,28], Mn (e.g., polymeric (RMIm)[Mn(NCS) 3 ], R = ethyl; and (DMDIm)[Mn(NCS) 4 ], DMDIM = 3,3methylenbis(1-methyl-imidazolium)) [29,30], and Cr (e.g., (RMIm)[Cr(NCS) 4 L x ], R = ethyl, nbutyl, x = 1: L = phenanthroline, 2,2 -bipyridine, x = 2: L = NH 3 ) [31][32][33]. These materials have been synthesized in order to lower the melting point of such substances and to investigate their properties with respect to ionic liquids (ILs).…”