PUMA publications for /user/b_schwederski/IAhttps://puma.ub.uni-stuttgart.de/user/b_schwederski/IAPUMA RSS feed for /user/b_schwederski/IA2024-03-28T13:23:48+01:00Chemistry of C-Trimethylsilyl-Substituted Heterocarboranes. 28. Selective Alkylation and Reactivity of \dqCarbons Adjacent\dq and \dqCarbons Apart\dq Tetracarba-nido-dodecaborane(12) Derivatives toward Group 1 and Group 2 Metals. Synthetic, Spectroscopic, and Structural Investigations on Lithium-, Sodium-, Potassium-, Cesium-, and Magnesium-Complexed C4B8 Carboraneshttps://puma.ub.uni-stuttgart.de/bibtex/27710d451094991120cbf5e8998ea4d51/b_schwederskib_schwederski2019-07-15T13:41:23+02:00DFT Group IA alkylation;magnesacarborane calcn calcn;mol crystal geometry magnesacarborane;heterocarborane magnesium metal metalation metallacarborane optimized prepn structure substituted substituted;DFT trimethylsilyl <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Narayan S. Hosmane" itemprop="url" href="/person/12377abb8cc8cc5b2f0aeb71f97076b36/author/0"><span itemprop="name">N. Hosmane</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Hongming Zhang" itemprop="url" href="/person/12377abb8cc8cc5b2f0aeb71f97076b36/author/1"><span itemprop="name">H. Zhang</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="John A. Maguire" itemprop="url" href="/person/12377abb8cc8cc5b2f0aeb71f97076b36/author/2"><span itemprop="name">J. Maguire</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Ying Wang" itemprop="url" href="/person/12377abb8cc8cc5b2f0aeb71f97076b36/author/3"><span itemprop="name">Y. Wang</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Temesgen Demissie" itemprop="url" href="/person/12377abb8cc8cc5b2f0aeb71f97076b36/author/4"><span itemprop="name">T. Demissie</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Thomas J. Colacot" itemprop="url" href="/person/12377abb8cc8cc5b2f0aeb71f97076b36/author/5"><span itemprop="name">T. Colacot</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Maria B. Ezhova" itemprop="url" href="/person/12377abb8cc8cc5b2f0aeb71f97076b36/author/6"><span itemprop="name">M. Ezhova</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Kai-Juan Lu" itemprop="url" href="/person/12377abb8cc8cc5b2f0aeb71f97076b36/author/7"><span itemprop="name">K. Lu</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Dunming Zhu" itemprop="url" href="/person/12377abb8cc8cc5b2f0aeb71f97076b36/author/8"><span itemprop="name">D. Zhu</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Thomas G. Gray" itemprop="url" href="/person/12377abb8cc8cc5b2f0aeb71f97076b36/author/9"><span itemprop="name">T. Gray</span></a></span></span> and 6 other author(s). </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Organometallics</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">19 </span></span>(<span itemprop="issueNumber">4</span>):
<span itemprop="pagination">497--508</span></em> </span>(<em><span>2000<meta content="2000" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Organometallics4497--508Chemistry of C-Trimethylsilyl-Substituted Heterocarboranes. 28. Selective Alkylation and Reactivity of {\dq}Carbons Adjacent{\dq} and {\dq}Carbons Apart{\dq} Tetracarba-nido-dodecaborane(12) Derivatives toward Group 1 and Group 2 Metals. Synthetic, Spectroscopic, and Structural Investigations on Lithium-, Sodium-, Potassium-, Cesium-, and Magnesium-Complexed C4B8 Carboranes192000DFT Group IA alkylation;magnesacarborane calcn calcn;mol crystal geometry magnesacarborane;heterocarborane magnesium metal metalation metallacarborane optimized prepn structure substituted substituted;DFT trimethylsilyl The carbons apart tetracarbon carborane nido-2,6-(R)2-4,12-(SiMe3)2-2,4,6,12-C4B8H8 [R = SiMe3 (I), Bu (II)] and several of its B-alkylated derivs. react with Mg metal in THF solvent to produce magnesacarboranes [e.g., (THF)2Mg(SiMe3)4(B-Bu-t)B4B7H7 (V)] in yields ranging from 57{\%} to 74{\%}. The magnesacarboranes were characterized by chem. anal. and IR and 1H, 11B, and 13C NMR spectroscopy and by single-crystal x-ray diffraction. Two types of cages were found, one in (THF)2Mg(SiMe3)4(B-Me)C4B7H7 (IV) and the other in (L)2Mg(SiMe3)2(R)2(B-Y)C4B7H7 [L = THF, R = SiMe3, Y = t-Bu (V); L = THF, R = SiMe3, Y = H (VI); (L)2 = TMEDA, R = Bu, Y = H (XI)]. Both cages showed electron-precise C and B atoms, as well as electron-deficient fragments. Approx. d. functional ab initio MO calcns. showed that the dianionic C4B8 cage can exist in a no. of energy-equiv. isomeric forms that can be trapped by a metal ion such as Mg. The reactions of I with the Group IA metals followed a different course in which two distinct steps occurred. The 1st step formed the paramagnetic intermediates which, in a slower step, reacted with a 2nd equiv. of the metal to give the diamagnetic [(SiMe3)4C4B8H8]2-. For the lighter metals, this dianion picked up a proton to give [(THF)4M][(SiMe3)4C4B8H9] [M = Li (VIII), Na (IX), K (X)] in 35-54{\%} yield. In the case of Cs, no protonation occurred and the final product was a polymeric dicesiacarborane, [exo-Cs(TMEDA)-1-Cs-(SiMe3)4C4B8H8]n (VII), isolated in 41{\%} yield. All were characterized by chem. anal. and IR and 1H, 11B, and 13C NMR spectroscopy; VII and VIII were addnl. characterized by single-crystal x-ray diffraction studies. In VIII-X the Group IA metal was solvated by four THF mols. and was not involved in the cage, while in VII one Cs occupied an apical position above a C3B3 open face of one carborane and bonded to a B3 face of a neighboring carborane. The 2nd Cs, solvated by a TMEDA mol., occupies an exo-polyhedral position and was not part of the polymeric chain. One carbons adjacent magnesacarborane, exo-(\textgreek{m}-H)3Mg(THF)3(SiMe3)2(Me)2C4B8H8 (XII), was also synthesized, in 81{\%} yield, by the reaction of the metal with the (SiMe3)2(Me)2C4B8H8 precursor. Single-crystal x-ray diffraction studies showed the compd. to be composed of an exo-polyhedral [Mg(THF)3]2+ that is loosely bound to a [(SiMe3)2(Me)2C4B8H8]2- cage. The carborane is best described as an 10-vertex arachno-(SiMe3)2C2B8H8 cage that subtends an electron-precise MeC:CMe fragment. [on SciFinder(R)]From ion pairs to radical complexes: Coordination compounds of reduced 2,2'-bipyridine with organometallic cationshttps://puma.ub.uni-stuttgart.de/bibtex/234b8e451fc4ded23d68a75cf45448afa/b_schwederskib_schwederski2019-07-15T13:41:23+02:00IA IIA bipyridine complex complex;ESR complex;Group complex;radical metal <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/1b316078e354c946a2bbd070b3a912fea/author/0"><span itemprop="name">W. Kaim</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Chemische Berichte</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">114 </span></span>(<span itemprop="issueNumber">12</span>):
<span itemprop="pagination">3789--3800</span></em> </span>(<em><span>1981<meta content="1981" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Chemische Berichte123789--3800From ion pairs to radical complexes: Coordination compounds of reduced 2,2'-bipyridine with organometallic cations1141981IA IIA bipyridine complex complex;ESR complex;Group complex;radical metal Reduced 2,2'-bipyridine (bipy-.bul.) forms paramagnetic complexes with organometallic cations RnM+ (M = metals of the first three groups of the periodic system; n = 0, 1, 2; R = Ph, Me). The persistent radicals [(RnM)bipy].bul. have been identified and studied by high resoln. ESR. Their ESR coupling consts. can be correlated excellently with results from HMO calcns. and exhibit a typical sequence of cations RnM+: K+, Na+, Li+, PhMg+, PhZn+, Me2Ga+, PhBe+, Ph2B+, R2Al+. This series exemplifies the continuous variation from genuine paramagnetic {\dq}ion pairs{\dq} to mostly covalently bonded radical complexes. [on SciFinder(R)]