“…The [Mn(NCS) 4 ] 2– anion of 5 features tetrahedral geometry of Mn atom ( τ 4 = 0.96). The [NCS] – groups are virtually linear and bonded with metal so that Mn–N–C angle is ≈ 167.84° that is consistent with the literature data …”
First examples of luminescent MnII thiocyanate complexes are presented. A series of such compounds has been synthesized via the reaction of Mn(NCS)2 with bis(phosphine oxides), Ph2P(O)–X–(O)PPh2, where X = CH2 (L1), CH2CH2 (L2), CH2CH2CH2 (L3), CH2C(=CH2)CH2 (L4), C(=CH2)C(=CH2) (L5) and C≡C (L6). The L1, L3 and L4 ligands, when reacted with Mn(NCS)2 on air (EtOH/acetone, r.t.), produce chelate complexes [MnII(O^O)2(NCS)2]. Under similar conditions, L5 gives ionic complex [MnII(L5)3][MnII(NCS)4], whereas L6 affords chain coordination polymer (CP) [MnII(L6)2(NCS)2]n. By contrast, ligand L2 results in formation of mixed‐valent chain CP [MnIIMnIII(L2)3(NCS)5]n. Complex [Mn(L4)2(NCS)2] and CP [Mn(L6)2(NCS)2]n display unique dual luminescence, i.e. the intraligand fluorescence (blue band) and MnII‐centered phosphorescence (red band), the ratio of which is largely modulated by excitation wavelength. Through this feature, the luminescence color of these complexes can be smoothly tuned from deep‐blue to red. Complex [Mn(L5)3][Mn(NCS)4] shows MnII‐based phosphorescence only.
“…The [Mn(NCS) 4 ] 2– anion of 5 features tetrahedral geometry of Mn atom ( τ 4 = 0.96). The [NCS] – groups are virtually linear and bonded with metal so that Mn–N–C angle is ≈ 167.84° that is consistent with the literature data …”
First examples of luminescent MnII thiocyanate complexes are presented. A series of such compounds has been synthesized via the reaction of Mn(NCS)2 with bis(phosphine oxides), Ph2P(O)–X–(O)PPh2, where X = CH2 (L1), CH2CH2 (L2), CH2CH2CH2 (L3), CH2C(=CH2)CH2 (L4), C(=CH2)C(=CH2) (L5) and C≡C (L6). The L1, L3 and L4 ligands, when reacted with Mn(NCS)2 on air (EtOH/acetone, r.t.), produce chelate complexes [MnII(O^O)2(NCS)2]. Under similar conditions, L5 gives ionic complex [MnII(L5)3][MnII(NCS)4], whereas L6 affords chain coordination polymer (CP) [MnII(L6)2(NCS)2]n. By contrast, ligand L2 results in formation of mixed‐valent chain CP [MnIIMnIII(L2)3(NCS)5]n. Complex [Mn(L4)2(NCS)2] and CP [Mn(L6)2(NCS)2]n display unique dual luminescence, i.e. the intraligand fluorescence (blue band) and MnII‐centered phosphorescence (red band), the ratio of which is largely modulated by excitation wavelength. Through this feature, the luminescence color of these complexes can be smoothly tuned from deep‐blue to red. Complex [Mn(L5)3][Mn(NCS)4] shows MnII‐based phosphorescence only.
“…This is about 1/3rd below (0.57 eV, see next section) the measured value. Usually, EHTB calculations tend to overestimate the actual gap value as a real structure with actual imperfections/inclusions providing doping centers and carrier shortways is not taken into account [88]. However, in this particular case, underestimation of the gap value serves as a sign of the presence of persisting electronic correlations that often lead to opening of the Mott gap in formally 3/4th filled upper band for ET compounds with +0.5 charge per ET radical cation [89].…”
A new molecular conductor, i.e., κ-(BEDT-TTF)2K+(18-crown-6)[CoII(NCS)4]∙(H2O), is semiconductive with substantial charge gap values (ΔE) of 0.57 eV (measured) and 0.37 eV (calculated). There is a full band separation despite formal average charge on BEDT-TTF of +0.5 and κ(kappa)-type packing of BEDT-TTF dimers that favors high conductivity. X-ray crystal structure analysis reveals complete charge ordering with full Coulomb charge on unique BEDT-TTF radical cations A (QA = +1), while unique molecules B are uncharged (QB = 0). Geometries of A (flat) and B (bent) differ considerably and are in accordance with the ascribing charges. Charge segregation is enhanced by forming tight face-to-face BEDT-TTF dimers AA (QAA = +2) and BB (QBB = 0). Strongly interacting double-charged dimers AA form “superstripes” running along a that are interleaved along b with chains of neutral dimers BB. Peculiar extremely thick (13.7 Å) four-decker insulating anion layers cast strong Coulomb potential onto the conductive layers predetermining charge localization in the latter.
“…By combining SMM properties and electrical conductivities, it was considered that negative magnetoresistance (MR) may appear in the molecular conductive magnets and be advantageous for the next-generation high-density information storage media and molecular spin qubits . Our group has been working on the functional conductive SMMs for a long time and published several systems by combining different molecular conductors of TTF, BEDT-TTF, M(dmit) 2 (dmit = 4,5-dimercapto-1,3-dithiole-2-dithione), BEDO-TTF (bis(ethylenedioxy)tetrathiafulvalene) with various SMMs such as [Co(pdms) 2 ] 2– , [Dy(NCS) 7 ] 4– , [Mn 2 ] 2+ clusters, and so on. − Other examples from several groups demonstrated conductive SMMs composed of Re, Mn, Ni, Tb, and Dy metal complexes with BEDT-TTF and BEDO-TTF conductors. − Here, we utilized a step-by-step electrocrystallization growth method to prepare a series of molecular heterostructures with different multiple building blocks composed of the (TTF) 2 M(pdms) 2 complex (M = Co(II), Zn(II), Ni(II)). The (TTF) 2 Co(pdms) 2 ( Co-TTF ) complex was reported to show electrical conduction and single-ion magnetism in our previous reports .…”
Assembling
conductive or magnetic heterostructures by bulk inorganic
materials is important for making functional electronic or spintronic
devices, such as semiconductive p-doped and n-doped silicon for P–N
junction diodes, alternating ferromagnetic and nonmagnetic conductive
layers used in giant magnetoresistance (GMR). Nonetheless, there have
been few demonstrations of conductive or magnetic heterostructures
made by discrete molecules. It is of fundamental interest to prepare
and investigate heterostructures based on molecular conductors or
molecular magnets, such as single-molecule magnets (SMMs). Herein,
we demonstrate the fabrication of a series of molecular heterostructures
composed of (TTF)2M(pdms)2 (TTF = tetrathiafulvalene,
M = Co(II), Zn(II), Ni(II), H2pdms = 1,2-bis(methanesulfonamido)benzene)
multiple building blocks through a well-controlled step-by-step electrocrystallization
growth process, where the Co(pdms)2, Ni(pdms)2, and Zn(pdms)2 anionic complex is a SMM, paramagnetic,
and diamagnetic molecule, respectively. Magnetic and SMM properties
of the heterostructures were characterized and compared to the parentage
(TTF)2Co(pdms)2 complex. This study presents
the first methodology for creating molecule-based magnetic heterostructural
systems by electrocrystallization.
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