Reaction of the Dioxane Complex of Dichlorogermylene with Siloxanes

The major organogermanium compounds formed by reactions of the dioxane complex of dichlorogermylene with hexamethyldisiloxane, octamethyltrisiloxane, and hexamethyltricyclotrisiloxane are bis(trimethylsiloxy)dichlorogermane, 3,3-dichloro-1,1,1,5,5,7,7,7-octamethyl-3-germa-2,4,6-trioxa-1,5,7-trisilaheptane, and a cyclic germatetrasiloxane.     

Complexes of Dichlorogermylene with Phosphine/Sulfoxide-Supported Carbone as Ligand

Due to their remarkable electronic features, recent years have witnessed the emergence of carbones L₂C, which consist in two donating L ligands coordinating a central carbon atom bearing two lone pairs. In this context, the phosphine/sulfoxide-supported carbone 4 exhibits a strong nucleophilic character, and here, we describe its ability to coordinate dichlorogermylene. Two original stable coordination complexes were obtained and fully characterized in solution and in the solid state by NMR spectroscopy and X-ray diffraction analysis, respectively. At 60 °C, in the presence of 4, the Ge(II)-complex 5 undergoes a slow isomerization that transforms the bis-ylide ligand into an yldiide.     

Metal‐Free Stabilization of Monomeric Antimony(I): A Carbene‐Supported Stibinidene

A diamidocarbene was coordinated to an antimony(III) dichloride Lewis acid. Subsequent reduction with magnesium gave a monomeric, formally antimony(I) fragment that is supported by the diamidocarbene. Spectroscopic, crystallographic, and computational analyses demonstrated that the carbene ligand engages the antimony(I) center in π‐backbonding resulting in a short (2.068(7) Å) Sb?C interaction that is comparable to those observed in known stibaalkenes.     

Reaction of a Dioxane Dichlorogermylene Complex with Compounds Containing C-H Bonds

The dioxane complex C₄H₈O₂·GeCl₂ reacts with compounds containing C-H bonds (C₆H₁₄, Me₃SiSiMe₃, C₄H₈O₂) with preferential formation of their trichlorogermyl derivatives.     

The Suprising Variety of Products from Reactions of P-P Bonds with Dichlorogermylene

Abstract

Insertion of dichlorogermylene (from GcCl₂-dioxane) into the P-P bonds of tetraalkyldiphosphanes ((PRR)₂ (2a: R, R ? i-Pr; 2b: R? t-Bu, R?i-Pr; 2C; R, R, ?t-Bu) leads 10 dichlorobis(dialkylphosphanyl)germanes 3a-c. With 2a. the insertion remains incomplete: 38 exists in an equilibrium with an adduct of diphosphane 2a with GeCI₂, Subsequently 3b and 3c undergo a-climinarions to dialkylchlorophosphanes Sb and Sc and the dimeric phosphanylgermylenes (RR PGeGl)² 4b and 4c [1]. Similar to the above (but in absence of dioxane), reacting the richlorogcrmylphosphane i-Pr(t-Bu)PGeCL₃, 7c [2] with the related trichlorosilylphosphanc i-Pr(t-Bu)PSiCl₃ provided a mixture of SiCl₄, 1c, 3c, 5c and 7c, 3a and 3c have been trapped as inert molybdenum complexes (CO)₄ MO(μ-PRR)₂ GeGl₂ 6a and 6c from cquilibrilia conraining la/ 2a/ 3a and 3c/ 4c / 5c / 7c respectively.     

Monomeric uni-ligated aluminates

The tetradentate ligand, common name Salban(But)H4 (N,N'-bis(2-hydroxy-3,5-di-tert-butylbenzyl)-1,4-diaminobutane) combines with appropriate amounts of LiAlH4 to produce the unique monomeric, uni-ligated aluminate [Salban(But)Al]Li(thf)2 (1) and the bimetallic derivative Salban(But)(AlH2Li(thf)2)2 (2).     

Monomeric analogues of halocidin

Halocidin is a heterodimeric antimicrobial peptide isolated from a tunicate, Halocynthia aurantium. We used the most active of the two monomers, an 18 residue amidated peptide, as lead structure and determined the role of each amino acid with alanine scanning. The results obtained led to the synthesis of a first generation of analogues with antimicrobial activity. The selectivity towards bacterial versus mammalian cells has been explored, as well as the specificity for gram positive (Staphylococcus aureus ATCC 25923) versus gram negative bacteria (Escherichia coli ATCC 25922). GRAVY (grand average of hydropathicity) was used to analyze the results.     

Monomeric lithium triazapentadienyl complexes

Treatment of 1,3,5-triazapentadienes [N{(C3F7)C(Mes)N}2]H and [N{(C3F7)C(Dipp)N}2]H (where Mes = 2,4,6-Me3C6H2; Dipp = 2,6-Pr(i)2C6H3) with n-BuLi in hexane, followed by the crystallization from hexane-THF mixture afforded the corresponding lithium 1,3,5-triazapentadienyl complexes as their THF solvates. X-Ray crystallographic analyses revealed that [N{(C3F7)C(Mes)N}2]Li(THF)2 and [N{(C3F7)C(Dipp)N}2]Li(THF) are monomeric in the solid state. [N{(C3F7)C(Mes)N}2]Li(THF)2 has a four-coordinate lithium center with a distorted tetrahedral geometry, and features a boat-shaped C2N3Li metallacycle. [N{(C3F7)C(Dipp)N}2]Li(THF) has a three-coordinate lithium atom and a planar, U-shaped C2N3 ligand backbone. The synthesis, solid-state structure, and 1H and 19F NMR spectroscopic details of [N{(C3F7)C(Mes)N}2]H are also reported.     

Monomeric phosphido and phosphinidene complexes of nickel

An unusual family of three-coordinate, d(8) and d(9) nickel phosphido and phosphinidene complexes containing the chelating 1,2-bis(di-tert-butylphosphino)ethane (dtbpe) ligand and a terminal PR(2)(-) or PR(2-) ligand have been prepared. The complexes (dtbpe)Ni[P(t-Bu)(2)] (2), [(dtbpe)Ni[=P(t-Bu)(2)](+)][PF(6)(-)] (3), [(dtbpe)Ni[=P(H)(dmp)](+)][PF(6)(-)] (5), and (dtbpe)Ni[=P(dmp)] (6) have been structurally characterized by single-crystal X-ray diffraction methods. The three-coordinate d(8) complexes exhibit Ni-P bond lengths and ligand geometries that indicate they participate in symmetry-allowed ligand-to-metal pi bonding involving phosphorus p-electrons and a metal-orbital of pi symmetry that lies in the Ni coordination plane. Compound 6 is a rare example of a late-transition-metal terminal phosphinidene complex.     

Six-Membered NHC Stabilized Monomeric Zinc Complexes

This paper describes the rare use of a 6-membered saturated N-heterocyclic carbene (NHC) known as 1,3-di(2,6-diisopropylphenyl) tetrahydropyrimidine-2-ylidene (abbreviated as 6-SIDipp) as a ligand in zinc chemistry. We report on the investigation of the reactions between 6-SIDipp and ZnX₂, which resulted in a range of new monomeric 6-SIDipp⋅ZnX₂ complexes (X=Et ( 1 ), Cl ( 2 ), Br ( 3 ), and I ( 4 )). We also prepared a new NHC zinc complex where the two substituents of the zinc atom are different, 6-SIDipp⋅Zn(Et)Br ( 7 ) through the reaction of the proligand [6-SIDippH]Br with ZnEt₂. We have observed that the reactions of complex 1 with sulfur and HBpin led to the removal of the ZnEt₂ moiety, resulting in the formation of a C=S double bond and a B−H activation product, respectively. Lastly, the reaction of 1 with five-membered NHCs led to the exchange of carbene and the formation of either 5-IDipp⋅ZnEt₂ ( 8 ) or 5-SIDipp⋅ZnEt₂ ( 9 ).     

Monomeric and polymeric copper and zinc tripyrrins

Neutral transition metal complexes of different alpha,omega-dimethyltripyrrins TrpyMX with M = Cu(II) and Zn(II) have been prepared with a variety of anionic halogeno and pseudohalogeno ligands X, and have been studied with respect to coordination modes and structural distortion. Only four- and five-coordinate species have been observed throughout the series. All four-coordinate species display unstrained, but distorted tetrahedral or strained and distorted square-planar coordination environments for zinc(II) and copper(II) species, respectively, thus following the expectations from simple ligand field arguments. Five-coordinate species do not form easily and were observed either in donor solvents or in the solid as 1D coordination polymers with distorted trigonal-bipyramidal coordination and different topologies.     

Synthesis of Novel Monomeric Dyes with Anthraquinone Residue

Two novel polymerizable dyes with anthraquinone residue have been prepared, and their structures were characterized by FTIR, ^1HNMR and EA.