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Molecular structure of 2 with anisotropic displacement parameters depicted at the 50% probability level. Hydrogen atoms are not shown for clarity. Symmetry generator *: 1−x, 1−y, 1−z. Selected bond lengths (Å) and bond angles (°): Br2−Zn1 2.4800(5) and 2.5143(5), Ge1−N3 1.838(3), Ge1−N2 1.959(2), Ge1−N1 1.972(2), Ge1−Zn1 2.4587(6), Br1−Zn1 2.3445(5), Zn1−Br2 2.5143(5); Zn1−Br2−Zn1 87.456(16), N3−Ge1−N2 111.48(12), N3−Ge1−N1 110.94(12), N2−Ge1−N1 66.73(10), N3−Ge1−Zn1 130.29(9), N2−Ge1−Zn1 112.13(9), N1−Ge1−Zn1 107.30(9), Br1−Zn1−Ge1 113.38(2), Br1−Zn1−Br2 115.07(2), Ge1−Zn1−Br2 117.743(18), Br1−Zn1−Br2 110.504(19), Ge1−Zn1−Br2 104.722(18), Br2−Zn1−Br2 92.543(16).
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Despite the explosive growth of germylene compounds as ligands in transition metal complexes, there is a modicum of precedence for the germylene zinc complexes. In this work, the synthesis and characterization of new germylene zinc complexes [PhC(NtBu)2Ge{N(SiMe3)2}→ZnX2]2 (X= Br (2) and I (3)) supported by (benz)‐amidinato germylene ligands are re...
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... TDDFT calculations are performed for studying in gaining deep insights about the electronic transitions and active sites of compounds [75][76][77][78][79]. Here, we have carried out the TD-DFT calculation of DPA, PDTC, and metal complexes (1)(2)(3)(4)(5)(6) to investigate the absorption properties. ...
In this study, we have investigated the structure, reactivity, bonding, and electronic transitions of DPA and PDTC along with their Ni-Zn complexes using DFT/TD-DFT methods. The energy gap between the frontier orbitals was computed to understand the reactivity pattern of the ligands and metal complexes. From the energies of FMO’s, the global reactivity descriptors such as electron affinity, ionization potential, hardness (η), softness (S), chemical potential (μ), electronegativity (χ), and electrophilicity index (ω) have been calculated. The complexes show a strong NLO properties due to easily polarization as indicated by the narrow HOMO–LUMO gap. The polarizability and hyperpolarizabilities of the complexes indicate that they are good candidates for NLO materials. Molecular electrostatic potential (MEP) maps identified electrophilic and nucleophilic sites on the surfaces of the complexes. TDDFT and NBO analyses provided insights into electronic transitions, bonding, and stabilizing interactions within the studied complexes. DPA and PDTC exhibited larger HOMO–LUMO gaps and more negative electrostatic potentials compared to their metal complexes suggesting the higher reactivity. Ligands (DPA and PDTC) had absorption spectra in the range of 250 nm to 285 nm while their complexes spanned 250 nm to 870 nm. These bands offer valuable information on electronic transitions, charge transfer and optical behavior. This work enhances our understanding of the electronic structure and optical properties of these complexes.
Gaussian16 program was used for the optimization of all the compounds. B3LYP functional in combination with basis sets, such as LanL2DZ for Zn, Ni and Cu while 6-311G** for other atoms like C, H, O, N, and S was used. Natural bond orbital (NBO) analysis is carried out to find out how the filled orbital of one sub-system interacts with the empty orbital of another sub-system. The ORCA software is used for computing spectral features along with the zeroth order regular approximation method (ZORA) to observe its relativistic effects. TD-DFT study is carried out to calculate the excitation energy by using B3LYP functional.
... The NPA charge analysis suggests that 2 contains a highly polar, covalent metal-metal single bond Ge δÀ -Zn δ + where the more electronegative germanium center forms the negative end (natural charges of 0.77 e (Ge) and 1.25 e (Zn)) ( Figure 2). The Wiberg Bond Index (WBI) of 0.40 for the GeÀ Zn bond in 2 is significantly lower than those in germanium(II) stabilized zinc halide complexes [PhC(NtBu) 2 Ge {N(SiMe 3 ) 2 }!ZnX 2 ] 2 (X = Br (III) and I (IV)) [45] and zincagermylene Ge(TBoN)(ZnL*) (II) with Ge!Zn (0.61) and GeÀ Zn (0.68-0.77) bonds. [31] This lower WBI value also shows the highly polar nature of the GeÀ Zn interaction in 2 compared to those in compounds II-IV. ...
In the presence of TMEDA (TMEDA=N,N,N’,N’‐tetramethylethylenediamine), zinc dihydride reacted with germanium(II) compounds (BDI−H)Ge (1) and [(BDI)Ge][B(3,5‐(CF3)2C6H3)4] (3) (BDI‐H = HC{(C=CH2)(CMe)(NAr)2}, BDI = [HC(CMeNAr)2]; Ar = 2,6‐ⁱPr2C6H3) by formal insertion of the germanium(II) center into the Zn−H bond of polymeric [ZnH2]n to give neutral and cationic zincagermane with a H−Ge‐Zn−H core [(BDI−H)Ge(H)‐(H)Zn(tmeda)] (2) and [(BDI)Ge(H)‐(H)Zn(tmeda)][B(3,5‐(CF3)2C6H3)4] (4), respectively. Compound 2 eliminated [ZnH2] giving diamido germylene 1 at 60 °C. Compound 2 and deuterated analogue 2‐d2 exchanged with [ZnH2]n and [ZnD2]n in the presence of TMEDA to give a mixture of 2 and 2‐d2. Compounds 2 and 4 reacted with carbon dioxide (1 bar) at room temperature to form zincagermane diformate [(BDI−H)Ge(OCHO)‐(OCHO)Zn(tmeda)] (5) and formate bridged digermylene [({BDI}Ge)2(μ‐OCHO)]⁺[B(C6H3(CF3)2)4] (6) along with zinc formate [(tmeda)Zn(μ‐OCHO)3Zn(tmeda)][B(C6H3(CF3)2)4] (7), respectively. The hydridic nature of the Ge−H and Zn−H bonds in 2 and 4 was probed by reactions with Brönsted and Lewis acids.
... Very recently, we have reported a germylene-zinc adduct and its reaction with sulfur, where the sulfur atom inserts into the Ge!Zn bond leading to Ge=S coordinated zinc complexes. [17] Inspired from this reaction, we wonder whether sulfur can insert into the ZnÀ Et bond of 1 and afford NHC supported zinc thiolate complexes, which have a modicum of precedence. [18] A further impetus comes from the synthetic difficulties associated with the accessing of zinc sulfide nanoparticles as mentioned by Rivard and coworkers. ...
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).
... Over the last decades, transition metal complexes have received much attention in the fields of catalysis, magnetism, medicine and material because their biocompatibility, various coordination modes, and catalytic properties [3][4][5]. Among these transition metal complexes, copper complexes with their versatile structures, redox behavior and physicochemical properties have been found to be useful as active agents in chemotherapeutic, catalytic applications. ...
C36H60Cl2CuN12, monoclinic, P21/c (no. 14), a = 8.3112(2) Å, b = 15.9513(4) Å, c = 17.1068(4) Å, β = 99.671(2)° V = 2235.69(9) Å3, Z = 2, Rgt(F) = 0.0523, wRref(F2) = 0.1606, T = 298(2) K.
Diverse reactivity of the bulky tris(trimethylsilyl)silyl substituent [Si(SiMe3)3], also known as the hypersilyl group, was observed for amidinate-supported dichloro- and phenylchloroborane complexes. Treatment of the dichloroborane with potassium tris(trimethylsilyl)silyl led to the activation of the backbone β-carbon center and formation of saturated four-membered heterocyclic chloroboranes R′{Si(SiMe3)3}C(NR)2BCl [R′ = Ph, R = Cy (3); R′ = Ph, R = iPr (6); R′ = tBu, R = Cy (8)], whereas the four-membered amidinate hypersilyl-substituted phenyl borane 4 {PhC(NCy)2B(Ph)[Si(SiMe3)3]} was observed for the case of an amidinate-supported phenylchloroborane. The highly deshielded ¹¹B NMR spectroscopic resonance and the distinct difference in the ²⁹Si NMR spectrum confirmed the presence of a σ-donating hypersilyl effect on compounds 3, 6, and 8. Reaction of 3 with the Lewis acid AlCl3 led to the formation of complex 11 in which an unusual cleavage of one of the C–N bonds of the amidinate backbone is observed. Nucleophilic substitution at the boron center of saturated chloroborane 3 with phenyllithium generated the phenylborane derivative 12, whereas the secondary monomeric boron hydride 13 was observed after treatment with alane (AlH3). All compounds (2–13) have been fully characterized by NMR spectroscopy and single-crystal X-ray structure determination studies.
The syntheses and stabilizations of germanium(II) cationic compounds have been known for long. Contemporary research have been engaged in tailoring the germanium(II) cationic species for applications in small‐molecule activation and catalysis. This article comprises the discussion on the three major types of germanium(II) cationic compounds: (1) germanium(II) monocation or germyliumylidene, (2) bis(germyliumylidene), and (3) germanium(II) dication. Herein, earlier reports on the stabilization of germanium(II) mono‐ and dications have been briefly mentioned. The article includes the latest findings on the stabilization of the germanium(II) cationic species. The major focus of the article has been on discussing how the choice of the supporting ligands becomes the determining factor for tuning the frontier electronics and hence the applicability of the cationic germanium(II) compounds. Examples of bond activation at the ambiphilic germanium(II) monocationic sites and their catalytic applications, element–ligand cooperative bond activations, transition metal‐main group cooperative catalysis, reverse polarization at the germanium(II) cationic site, cooperative interactions between two germanium(II) cationic sites, leading to organic transformations, etc., which are some of the remarkable findings, have been discussed. This overview on the advancements made in this field will provide a background knowledge for further explorations.
Understanding the photochemistry of boron nitrogen (BN)-containing compounds is an important aspect to enhance the various optical and electronic applications. In this work, we have explored the structure, bonding, reactivity, electronic absorption (UV–Vis), and light harvesting efficiency (LHE) of a series of BN3 ring and open-chain systems. The frontier molecular orbitals (FMO) analysis found that ring systems have a low HOMO–LUMO energy gap as compared to the open-chain systems which insinuates the feasibility of ring systems in the optoelectronic materials. Also, the molecular electrostatic potential (MEP) maps have been computed to pursue the electrophilic and nucleophilic sites available at the surface of the compound. Interestingly, we have found that the open-chain compounds show more molecular charge distribution range rather than the ring compounds. The investigation of photophysical properties showed that the UV–Vis absorption significantly red-shifted in BN3 ring systems as compared to open-chain counterparts. Furthermore, light harvesting efficiency (LHE) was also found higher in the ring systems as compared to the BN3 open-chain systems. Moreover, the computed structural parameters are found well corroborated with the available X-ray data.
Structures of all compounds were optimized by using density functional theory (DFT) method, with M06-2X/6-31G(d,p) level. All the calculations in this work are carried out in Gaussian 16 program package. GaussView6.1 software was used for the modeling of initial geometries and for the plotting of MEP plots. To account the solvent effect on geometries the polarized continuum model (PCM) was used and tetrahydrofuran (THF) taken as solvent. The NBO6.0 program (incorporated in G16 software) was used for the exploration of bonding nature and stabilization energies of B-N bond. The absorption spectra were simulated by using ORCA 4.2 program.
Germacarbonyl compounds are the germanium analogs of carbonyl compounds requiring an inert atmosphere for stability. Making these compounds survive the ambient conditions was not feasible given the lability of the Ge[double bond, length as m-dash]E bonds (E = O, S, Se, Te). However, the first examples of germacarbonyl compounds synthesized under ambient conditions by taking advantage of dipyrromethene ligand stabilization are detailed here; the isolated compounds are thiogermanone 3, selenogermanone 4, thiogermacarboxylic acid 6, selenogermacarboxylic acid 7, thiogermaester 9, selenogermaester 10, thiogermaamide 12, and selenogermaamide 13 with Ge[double bond, length as m-dash]E bonds (E = S, Se). Compounds 12 and 13 can react under atmospheric conditions with copper(i) halides offering air and water stable monomeric 14-15 and dimeric 16-19 copper(i) complexes (halide = Cl, Br, I). Apart from just binding, selectivity was also observed; thiogermaamide 12 and selenogermaamide 13 bind CuCl and CuBr, respectively, when treated with a mixture of copper(i) halides.
The organometallic chemistry of germanium is enormous and encompasses several fast-growing research areas. Prominent fields in germanium(IV) chemistry include acyclic/cyclic compounds with single/multiple bonds between germanium atoms and various elements/metals in the periodic table that range from hydrogen to transition metals through the main group elements. Polymers with germanium atoms in the main chains are also pursued with interest. In the low-valent chemistry of germanium, germylenes play a crucial role along with germanium (I) compounds and germylones. The last fifteen years of developments in all these areas of germanium chemistry are methodically presented in this chapter focusing synthesis and reactivity.
