Heptanuclear [FeIII6CrIII]3+ Complexes Experimentally Studied by Means of Magnetometry, X-ray Diffraction, XAS, XMCD and Spin-Polarized Electron Spectroscopy in Cross-Comparison with [MnIII6CrIII]3+ Single-Molecule Magnets

Dohmeier N, Helmstedt A, Müller N, et al. Heptanuclear [FeIII6CrIII]3+ Complexes Experimentally Studied by Means of Magnetometry, X-ray Diffraction, XAS, XMCD and Spin-Polarized Electron Spectroscopy in Cross-Comparison with [MnIII6CrIII]3+ Single-Molecule Magnets. Magnochemistry. 2016;2(1): 5

Synthesis, crystal structure, and application of the oxonium acid [H(OEt2)(2)](+)[B(C6F5)(4)](-)

Jutzi P, Müller C, Stammler A, Stammler H-G. Synthesis, crystal structure, and application of the oxonium acid [H(OEt2)(2)](+)[B(C6F5)(4)](-). Organometallics. 2000;19(7):1442-1444.The reaction of LiB(C6F5)(4) with HCl in diethyl ether afforded the new oxonium acid [H(OEt2)2](+)-[B(C6F5)(4)](-) (1) as a colorless crystalline solid, which was characterized by NMR spectroscopy, by elemental analysis, and by single-crystal X-ray diffraction. The application of 1 is demonstrated in the generation of the complex: {[eta(5)-C5H3(CH2CH2NMe2)CMe2-eta(5)-C13H8]ZrCH3}(+)- [B(C6F5)(4)](-) (3) containing an intramolecularly donor-stabilized alkylzirconocene cation

Reactivity of Ferriophosphaalkene [(η5-C5Me5)(CO)2Fe-P=C(NMe2)2] and Ferrioarsaalkene [(η5-C5Me5)(CO)2FeAs=C(NMe2)2] Towards Tromethylaluminium, -gallium and -indium

Weber L, Scheffer MH, Stammler H-G, Stammler A. Reactivity of Ferriophosphaalkene [(η5-C5Me5)(CO)2Fe-P=C(NMe2)2] and Ferrioarsaalkene [(η5-C5Me5)(CO)2FeAs=C(NMe2)2] Towards Tromethylaluminium, -gallium and -indium. European Journal of Inorganic Chemistry. 1999;(9):1607-1611.Reaction of equimolar amounts of the ferriophosphaalkene [(eta(5)-C5Me5)(CO)(2)FeP=C(NMe2)(2)] (1a) or the ferrioarsaalkene [(eta(5)-C5Me5)(CO)(2)FeAs=C(NMe2)(2)] (1b) with trimethylaluminium, trimethylgallium and trimethylindium afforded the adducts [(eta(5)-C5Me5)(CO)(2)FeE{MMe3}C(NMe2)(2)] with E = P; M = Al (2a), Ga (3a), In (4a) and E = As; M = Al (2b), Ga (3b), and In (4b). These compounds feature eta(1)-coordination of the phosphaalkene or the arsaalkene ligand towards the Lewis acid via the pnictogen atom. The molecular structures of 2a and 3a were elucidated by X-ray diffraction analyses

Palladium-catalyzed insertion of alkynes into the Sn-B bond of a 2-stannyl-2,3-dihydro-1H-1,3,2-diazaborole and X-ray structure analyses of 1,3-di-tert-butyl-2[(Z)-2-phenyl-2-trimethylstannylethenyl]-2,3-dihydro- 1H-1,3,2-diazaborole and 1,3-di-tert-butyl-2[(Z)-1-ethyl-2-phenyl-2-trimethylstannylethenyl]-2,3- dihydro-1H-1,3,2-diazaborole

Weber L, Wartig HB, Stammler H-G, Stammler A, Neumann B. Palladium-catalyzed insertion of alkynes into the Sn-B bond of a 2-stannyl-2,3-dihydro-1H-1,3,2-diazaborole and X-ray structure analyses of 1,3-di-tert-butyl-2[(Z)-2-phenyl-2-trimethylstannylethenyl]-2,3-dihydro- 1H-1,3,2-diazaborole and 1,3-di-tert-butyl-2[(Z)-1-ethyl-2-phenyl-2-trimethylstannylethenyl]-2,3- dihydro-1H-1,3,2-diazaborole. Organometallics. 2000;19(15):2891-2895.Reaction of equimolar amounts of 1,3-di-tert-butyl-2-trimethylstannyl-2,3-dihydro-1H,3,2-diazaborole (1) with a series of alkynes R-1-C equivalent to C-R-2 (2)(a: R-1 = H, R-2 = Ph; b: H, 4-ClC6H4; c: H, 4-BrC6H4; d: Ph, Ph; e: Me, Ph; f: Et, Ph; g: H, n-C4H9; h: Et, Et; i: H, n-C6H13) in the presence of a catalytic amount of [Pd(PPh3)(4)] (2 mol %) regioselectively afforded high yields of the alkenes (Z)-R-1[B]C=C(R-2)SnMe3 (3a-h) ([B] = tBuNCH=CHN(tBu)B] as the result of a cis-addition of the BSn bond of 1 to the acetylenic triple bond of 2. Spectroscopic evidence and X-ray structural analyses of 3a and 3f revealed that the bulky borolyl unit was added to the least sterically hindered end of the CC multiple bond

Syntheses and structures of η(1)-phosphaallyl, η(1)-arsaallyl, and eta(1)-stibaallyl iron complexes [(eta(5)-C5Me5)(CO)(2)Fe-E(SiMe3)C(OSiMe3)=CPh2] (E = P, As, Sb)

Weber L, Uthmann S, Kleinebekel S, Stammler H-G, Stammler A, Neumann B. Synthese und Struktur von η1-Phosphaallyl-, η1-Arsaallyl und η1-Stibaallyleisen-Komplexen [(η5-C5Me5)(CO)2Fe–E(SiMe3)C(OSiMe3)=CPh2] (E = P, As, Sb). Zeitschrift für Anorganische und Allgemeine Chemie. 2000;626(8):1831-1836.The reaction of equimolar amounts of [(eta(5)-C5Me5)(CO)(2)Fe-E(SiMe3)(2)] (1a: E = P; 1b: As; 1c: Sb) and diphenylketene afforded the eta(1)-phosphaallyl-, eta(1)-arsaallyl-, and eta(1)-stibaallyl complexes [(eta(5)-C5Me5)(CO)(2)Fe-E(SiMe3)C(OSiMe3)=CPh2] (2a: E = P; 2b: As; 2c: Sb). The molecular structures of 2b and 2c were elucidated by single crystal X-ray analyses

Does Symmetry Influence the Properties of [(Mn6CrIII)-Cr-III](3+) Single-Molecule Magnets?

Höke V, Stammler A, Bögge H, Glaser T. Does Symmetry Influence the Properties of [(Mn6CrIII)-Cr-III](3+) Single-Molecule Magnets? ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE. 2018;644(21):1354-1360.The triplesalen complex [(Mn6CrIII)-Cr-III](ClO4)(3) was synthesized and characterized by single-crystal X-ray diffraction, UV/Vis/NIR spectroscopy, and DC and AC magnetic susceptibilities. The molecular structure is D-3 symmetric, whereas all other salts and solvates of [(Mn6CrIII)-Cr-III](3+) are S-6 symmetric. The UV/Vis/NIR spectrum of D-3 symmetric [(Mn6CrIII)-Cr-III](3+) is almost identical to that of S-6 symmetric [(Mn6CrIII)-Cr-III](3+) demonstrating that the electronic structure is not significantly perturbed by the symmetry variation. The magnetic data of D-3 symmetric [(Mn6CrIII)-Cr-III](3+) is also similar to those of S-6 symmetric [(Mn6CrIII)-Cr-III](3+) with antiferromagnetic J(Mn-Mn) exchange coupling. This is in contrast to the ferromagnetic J(Mn-Mn) exchange coupling in the chiral (RR)[(Mn6CrIII)-Cr-III](3+) synthesized with a chiral triplesalen derivative. Due to the chirality, (RR)[(Mn6CrIII)-Cr-III](3+) is also of D-3 symmetry. However, its UV/Vis/NIR spectrum differs to those of D-3 and S-6 symmetric [(Mn6CrIII)-Cr-III](3+). This indicates that the electronic and magnetic properties of (RR)[(Mn6CrIII)-Cr-III](3+) are not different to those of [(Mn6CrIII)-Cr-III](3+) due to the symmetry variation but due to the specific properties of the two triplesalen ligands

Enhancing the Ferromagnetic Coupling in Extended Phloroglucinol Complexes by Increasing the Metal SOMO - Ligand Overlap: Synthesis and Characterization of a Trinuclear CoII3 Triplesalophen Complex

Oldengott J, Stammler A, Bögge H, Glaser T. Enhancing the Ferromagnetic Coupling in Extended Phloroglucinol Complexes by Increasing the Metal SOMO - Ligand Overlap: Synthesis and Characterization of a Trinuclear CoII3 Triplesalophen Complex. Dalton trans. 2015;44(21):9732-9735.The triplesalophen complex [(baron(Me))Co-3(II)] has been synthesized and characterized. The low-spin Co-II ions possess an (2)A(2) ground state with the magnetic orbitals of d(yz) type. These are well oriented for a strong pi overlap with the bridging phloroglucinol, which results in the strongest ferromagnetic interactions by the spin-polarization mechanism for a 3d phloroglucinol complex

Synthesis and Characterization of a mu-Oxo-Bridged Diferric Complex: An Attempt to Influence the Configuration by Changing the Spacer

Aschenbrenner M, Stammler A, Bögge H, Glaser T. Synthesis and Characterization of a mu-Oxo-Bridged Diferric Complex: An Attempt to Influence the Configuration by Changing the Spacer. ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE. 2018;644(22):1439-1444.The mu-oxo-bridged diferric complex [(susan(Pr)){(FeCl)-Cl-III(mu-O)(FeCl)-Cl-III}](ClO4)(2) was synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, FT-IR, UV/Vis/NIR, and Mossbauer spectroscopies as well as magnetic and electrochemical measurements. The properties are compared to the corresponding values for the complex [(susan){(FeCl)-Cl-III(mu-O)(FeCl)-Cl-III}](ClO4)(2), which exhibits a central ethylene spacer, whereas [(susan(Pr)){(FeCl)-Cl-III(mu-O)(FeCl)-Cl-III}](ClO4)(2) has a propylene spacer. Both complexes exhibit a trans configuration of the two terminal chloride ligands. This configuration induces more steric demand in the case of the propylene spacer, which results in a rotation of the two octahedral units along the Fe-(mu-O)-Fe axis and a tilting of the Fe-N bonds of the diamine spacer. The iron bond lengths are only slightly elongated by the steric demand of the propylene spacer, which is reflected by almost no change in the Mossbauer spectrum. However, the UV/Vis/NIR spectra show a stronger ligand field for [(susan(Pr)){(FeCl)-Cl-III(mu-O)(FeCl)-Cl-III}](ClO4)(2). The slightly longer iron bond lengths result in less electron donation, which is reflected by an anodic shift of 120 mV for the oxidation of the complex. This comparison provides more information on the variation of the properties of the diferric complexes by slight changes in the second coordination sphere

From Triplesalen to Triplesalalen and Triplesalan - Strengthening the Aromatic Character of the Ligand Backbone in Extended Phloroglucinol Ligands by Prevention of Heteroradialene Formation

Feldscher B, Stammler A, Bögge H, Glaser T. From Triplesalen to Triplesalalen and Triplesalan - Strengthening the Aromatic Character of the Ligand Backbone in Extended Phloroglucinol Ligands by Prevention of Heteroradialene Formation. European Journal Of Inorganic Chemistry. 2013;2013(3):388-397.The methyl-protected triplesalalen ligand Me(3)H(3)talalen(tBu2) was synthesized from 2,4,6-tris(bromomethyl)-1,3,5-trimethoxybenzene and three equivalents of the secondary amine 4,6-di-tert-butyl-2-{[2-(methylamino)ethylimino]methyl}phenol. A reduction with NaBH4 afforded the methyl-protected triplesalan ligand Me(3)H(3)talan(tBu2). Deprotection efforts of the methyl-protected Me(3)H(3)talalen(tBu2) ligand with Lewis acids were unsuccessful. Using Cu-II ions as Lewis acid resulted in the formation of the methyl-protected triplesalalen complex [(Me(3)H(3)talalen(tBu2)){Cu-II(H2O)}(3)](ClO4)(3), which could be characterized by single-crystal X-ray diffraction. The bond-length analysis reveals the aromatic character of the central backbone without heteroradialene contribution, and this is corroborated by NMR spectra of the ligands, which exhibit a singlet assigned to the benzylic protons at delta = 3.50 ppm in the H-1 NMR and a resonance typical for an aromatic C-Ar-O group at delta = 160.0 ppm in the C-13 NMR spectroscopy. FTIR spectra of the ligands and of the complexes exhibit the typical features of a central aromatic unit and do not show the characteristic intense bands for vibrations of the exocyclic C=C and C=O double bonds of a heteroradialene. Additionally, the characteristic strong absorption bands for heteroradialenes in the 26000-35000 cm(-1) region are absent in the UV/Vis/NIR spectra. The electrochemistry exhibits the reversible oxidation of the terminal phenolates of [(Me(3)H(3)talalen(tBu2)){CuII(H2O)}3](ClO4)(3) at +0.72 V vs Fc(+)/Fc, and the magnetic measurements reveal an uncoupled behavior due to the apical coordination of the central methoxy groups to the Cu-II ions