Nicole Harmgarth

Crystal and mol­ecular structures of two silver(I) amidinates, including an unexpected co-crystal with a lithium amidinate

In the dimeric silver(I) amidinates [Ag{RC(NR′)2}]2 (R = Ph, cyclopropylalkynyl; R′ = Cy, iPr), a centrosymmetric planar Ag2N4C2 ring with strictly linearly coordinated silver ions is present. [Ag{cyclo-C3H5—C≡C–C(NCy)2}]2 forms a 1:1 co-crystal with the related lithium derivative [Li{cyclo-C3H5—C≡C–C(NCy)2}(THF)]2, in which the lithium component exhibits a typical dimeric ladder structure.

Plasma-assisted atomic layer deposition of germanium antimony tellurium compounds

Plasma atomic layer deposition of Ge-Sb-Te (GST) thin films using halogen-free precursors is reported. The Sb and Te precursors tris(aziridinyl)antimony (III) (Sb[cyclo-NC2H4]3) and di-n-butylditelluride [Te2(n-C4H9)2] were employed for the first time in the deposition of GST thin films. Conformal filling of trenches has been demonstrated. The film thickness ratio between the top and the wall/bottom of trenches was evaluated: for “wide” (7:1 aspect ratio) trenches—dbottom/dtop ≈ 0.65, and for “narrow” (23:1 aspect ratio) trenches dwall/dtop > 0.63. Due to the use of amino precursors the as-deposited GST films were doped with nitrogen.

Three new types of transition metal carboranylamidinate complexes

Three new types of transition metal carboranylamidinate complexes are reported. The tetranuclear Mn(ii) complex Mn4Cl6[(o-C2B10H10)C(NiPr)(NHiPr)]2(THF)4·THF (2) was prepared by treatment of anhydrous MnCl2 with Li[(o-C2B10H10)C(NiPr)(NHiPr)] ([double bond, length as m-dash]Li[HLiPr]) in THF, while the analogous reaction with FeCl2 afforded ionic [Li(DME)3][FeCl2{(o-C2B10H10)C(NiPr)(NHiPr)}] (3). The dinuclear Mo(ii) complex Mo2[(o-C2B10H10)C(NiPr)(NHiPr)]2(OAc)2·2THF (4), obtained from Mo2(OAc)4 and 2 equiv. of Li[HLiPr], represents the first example of a M-M multiple bond stabilized by carboranylamidinate ligands. All title compounds were structurally characterized by single-crystal X-ray diffraction. The M-M bonding in compound 4 has been further elucidated through Complete Active Space Self Consistent Field (CASSCF) calculations.

Electronic and Geometric Structures of Paramagnetic Diazadiene Complexes of Lithium and Sodium

Abstract The electronic and molecular structures of the lithium and sodium complexes of 1,4‐bis(2,6‐diisopropylphenyl)‐2,3‐dimethyl‐1,4‐diazabutadiene (Me2DADDipp) were fully characterized by using a multi‐frequency electron paramagnetic resonance (EPR) spectroscopy approach and crystallography, together with density functional theory (DFT) calculations. EPR measurements, using T 1 relaxation‐time‐filtered pulse EPR spectroscopy, revealed the diagonal elements of the A and g tensors for the metal and ligand sites. It was found that the central metals in the lithium complexes had sizable contributions to the SOMO, whereas this contribution was less strongly observed for the sodium complex. Such strong contributions were attributed to structural specifications (e.g. geometrical data and atomic size) rather than electronic effects.

Bright Photoluminescence of [{(CptBu2)2Ce(μ-Cl)}2]: A Valuable Technique for the Determination of the Oxidation State of Cerium

The synthesis and photoluminescence properties of the bright-yellow organocerium complex [{(CptBu2 )2 Ce(μ-Cl)}2 ] (CptBu2 =1,3-di(tert-butyl)cyclopentadienyl) are presented. This coordination compound exhibits highly efficient photoluminescence within the yellow-light wavelength range, with a high internal quantum yield of 61(±2) % at room temperature. The large red shift is attributed to the delocalizing ability of the aromatic ligands, whilst its quantum yield even makes this compound competitive with Ce3+ -activated LED phosphors in terms of its photoluminescence efficiency (disregarding its thermal stability). A bridging connection between two crystallographically independent Ce3+ ions is anticipated to be the reason for the highly efficient photoluminescence, even up to room temperature. The emission spectrum is characterized by two bands in the orange-light range at both 10 K and room temperature, which are attributed to the parity-allowed transitions 5d1 (2 D3/2 )→4f1 (2 F7/2 ) and 5d1 (2 D3/2 )→4f1 (2 F5/2 ) of Ce3+ , respectively. The photoluminescence spectra were interpreted in relation to the structure and vibrational modes of the coordination compound. The spectra and optical properties indicate that trivalent cerium ions are the dominant species in the ground state, which also resolves an often-encountered ambiguity in organocerium compounds. This result shows that photoluminescence spectroscopy is a versatile tool that can help elucidate the oxidation state of Ce in such compounds.

CCDC 1536243: Experimental Crystal Structure Determination

Related Article: Nicole Harmgarth, Phil Liebing, Andreas Forster, Liane Hilfert, Sabine Busse, Frank T. Edelmann|2017|Eur.J.Inorg.Chem.||4473|doi:10.1002/ejic.201700500

CCDC 1536247: Experimental Crystal Structure Determination

Related Article: Nicole Harmgarth, Phil Liebing, Andreas Forster, Liane Hilfert, Sabine Busse, Frank T. Edelmann|2017|Eur.J.Inorg.Chem.||4473|doi:10.1002/ejic.201700500

CCDC 1536246: Experimental Crystal Structure Determination

Related Article: Nicole Harmgarth, Phil Liebing, Andreas Forster, Liane Hilfert, Sabine Busse, Frank T. Edelmann|2017|Eur.J.Inorg.Chem.||4473|doi:10.1002/ejic.201700500

CCDC 1536245: Experimental Crystal Structure Determination

Related Article: Nicole Harmgarth, Phil Liebing, Andreas Forster, Liane Hilfert, Sabine Busse, Frank T. Edelmann|2017|Eur.J.Inorg.Chem.||4473|doi:10.1002/ejic.201700500

CCDC 1536248: Experimental Crystal Structure Determination

Related Article: Nicole Harmgarth, Phil Liebing, Andreas Forster, Liane Hilfert, Sabine Busse, Frank T. Edelmann|2017|Eur.J.Inorg.Chem.||4473|doi:10.1002/ejic.201700500