Two synthetic approaches have until now been used to synthesize transition metal complexes having a tridentate (pincer or tripod) PEP tetryl (E=Si, Ge, Sn) ligand. These approaches differ in the ...metal‐free precursor, tetrelane or tetrylene, that gives rise to the corresponding PEP tetryl ligand. Tetrelanes (PSiP silanes, PGeP germanes and PSnP stannanes and simple phosphane‐free stannanes) have led to tetryl ligands by oxidatively adding an E−X bond (X=H, C or halogen in most cases) to the metal atom of a low‐valent transition metal complex, whereas tetrylenes (PGeP germylenes and PSnP stannylenes) have led to tetryl ligands upon insertion of their E atom into an M−X bond (X=Cl in most cases) of the metal precursor or through a derivatization of the E atom after the tetrylene fragment is coordinated to the metal. For each synthetic approach, all the currently known types of PEP tetryl ligand frameworks that have been found in transition metal complexes are presented and discussed in this review.
PEP ligands: Two general synthetic approaches to the synthesis of tridentate PEP tetryl (E=Si, Ge, Sn) metal complexes are presented as a function of the metal‐free precursor, tetrelane or tetrylene, that gives rise to the final PEP tetryl ligand. For each approach, all the currently known types of PEP tetryl ligand frameworks that have been found in their corresponding complexes are presented and discussed.
•The synthesis, reactivity and catalytic activity of transition-metal derivatives of heavier tetrylene amidinates (amidinato-HT–TM complexes) are reviewed.•Most of the hitherto reported ...amidinato-HT–TM complexes are silylene or germylene derivatives.•Amidinato-HTs are strong electron-donating ligands, stronger than N-heterocyclic carbenes (NHCs) in many cases.•The electronic and steric properties of amidinato-HTs can be easily tuned.
The transition-metal (TM) chemistry of heavier tetrylenes (HTs), also known as heavier carbene analogs, group 14 metalenes or group 14 metalylenes (compounds containing Si, Ge, Sn or Pb in +2 oxidation state), has experienced an exponential growth in the last few years because new families of HTs have emerged to the main-group chemistry arena. One of these families is characterized by the presence of an amidinato group attached to the group 14 element. Although the first report dealing with amidinato-HT–TM complexes appeared only seven years ago, nearly one hundred TM complexes containing amidinato-HT ligands are currently known and, remarkably, some of them have already been recognized as catalyst precursors for useful transformations of organic substrates (Sonogashira, Kumada and Negishi cross-couplings, ketone hydrosilylations, cycloadditions, arene C–H borylations, etc.). Thus, amidinato-HTs have emerged as promising alternatives to widely used classical ligands, such as phosphines or N-heterocyclic carbenes. This review comprehensively surveys the TM chemistry of amidinato-HTs published up to the end of 2014, examining not only the synthesis and characterization of these complexes, but paying special attention to reactivity studies, theoretical investigations and catalytic applications.
This review article focuses on amidinatotetrylenes that potentially can (or have already shown to) behave as bi‐ or tridentate ligands because they contain at least one amidinatotetrylene moiety ...(silylene, germylene or stannylene) and one (or more) additional coordinable fragment(s). Currently, they are being widely used as ligands in coordination chemistry, small molecule activation and catalysis. This review classifies those that have been isolated as transition metal‐free compounds into five families that differ in the position(s) of the donor group(s) (D) on the amidinatotetrylene moiety, namely: ED{R1NC(R2)NR1}, EX{DNC(R2)NR1}, EX{R1NC(D)NR1}, EX{DNC(R2)ND} and E{R1NC(R2)ND}2 (E=Si, Ge or Sn). Those that do not exist as transition metal‐free compounds but have been observed as ligands in transition metal complexes are cyclometallated and ring‐opened amidinatotetrylene ligands. This article presents schematic descriptions of their structures, the approaches used for their syntheses and a quick overview of their involvement (as ligands) in transition metal‐catalysed reactions. The literature is covered up to the end of 2023.
This review article classifies the title compounds into families that differ in the position(s) of the donor group(s) D on the corresponding amidinatotetrylene moiety (E=Si, Ge, Sn), schematically presents the structures of the members of each family, and describes the synthetic approaches utilized for their preparation and their use as ligands in transition metal‐catalysed reactions.
This review article collects and discusses the syntheses of the currently known metal‐free heavier tetrylenes having a PEP pincer topology (E = tetrel atom) as well as their transition metal ...derivative chemistry. To date, only five PGeP germylenes and two PSnP stannylenes have been isolated. These compounds have been successfully synthesized by treating GeCl2(diox) (diox = 1,4‐dioxane), GeCl2(NHC) (NHC = N‐heterocyclic carbene) or SnCl2 with two equivalents of an appropriate lithiated phosphine. Their transition metal chemistry is dominated by processes in which, in addition to the coordination of one or both phosphane groups, the E atom ends inserted into M–M or M–X (X = anionic group) bonds. Only in a few occasions a simple coordination of the tetrylene fragment (as a neutral two‐electron‐donor ligand) has been observed. The structural and bonding characteristics of the metal‐free PEP tetrylenes and of relevant examples of their transition metal derivatives are also surveyed.
This minireview surveys, in an approximate chronological order of publication, the synthetic aspects of the currently known isolable (metal‐free) heavier tetrylenes that have a PEP (E = tetrel atom) pincer topology as well as their reactivity with transition metal complexes.
Heavier tetrylenes (HTs), which are the heavier analogues of carbenes, have been used as ligands in transition metal chemistry for more than 50 years. Having in mind that cyclometallation is a ...valuable tool to modify ligand scaffolds, with important implications in inorganic and organic chemistry, this microreview discusses in detail the reactions that have afforded complexes with cyclometallated HTs. To date, eight HT ligands, covering only silylenes and germylenes, have been reported to undergo cyclometallation, all of them on late transition metals. Structural and spectroscopic data of the isolated complexes as well as mechanistic information related to the cyclometallation processes are collected and discussed. Additionally, this minireview also surveys the catalytic applications found so far for cyclometallated HT complexes.
Cyclometallation is a commonly used method to make metal–carbon σ bonds and to modify ligand scaffolds, with important implications in catalysis. This microreview surveys the synthesis and reactivity of transition metal complexes containing cyclometallated heavier tetrylene ligands (only silylenes and germylenes are currently known), paying particular attention to their catalytic applications.
The growing generation of data and their wide availability has led to the development of tools to produce, analyze, and store this information. Computational chemistry studies, especially catalytic ...applications, often yield a vast amount of chemical information that can be analyzed and stored using these tools. In this manuscript, we present a framework that automatically performs a fully automated procedure consisting of the transfer of an adsorbate from a known metal slab to a new metal slab with similar packing. Our method generates the new geometry and also performs the required calculations and analysis to finally upload the processed data to an online database (ioChem‐BD). Two different implementations have been built, one to relocate minimum energy point structures and the second to transfer transition states. Our framework shows good performance for the minimum point location and a decent performance for the transition state identification. Most of the failures occurred during the transition state searches and needed additional steps to fully complete the process. Further improvements of our framework are required to increase the performance of both implementations. These results point to the avoidhuman path as a feasible solution for studies on very large systems that require a significant amount of human resources and, in consequence, are prone to human errors.
Computational chemistry studies, especially on materials and catalytic systems, typically generate a vast amount of chemical information that is, however, not often shared according to FAIR data principles. Here, a framework is presented to transform computational results into a true seamless information science that can be interactively read, dynamically searched, analyzed, and mined while ensuring the transferability among different fields through metadata storage, with reduced human intervention.
The reactivity of the PGeP germylene 2,2’‐bis(di‐isopropylphosphanylmethyl)‐5,5’‐dimethyldipyrromethane‐1,1’‐diylgermanium(II), Ge(pyrmPiPr2)2CMe2, with late first‐row transition metal (Fe‐Zn) ...dichlorides has been investigated. All reactions led to PGeP pincer chloridogermyl complexes. The reactions with FeCl2 and CoCl2 afforded paramagnetic square planar complexes of formula MCl{κ3P,Ge,P‐GeCl(pyrmPiPr2)2CMe2} (M=Fe, Co). While the iron complex maintained an intermediate spin state (S1; μeff=3.0 μB) over the temperature range 50–380 K, the effective magnetic moment of the cobalt complex varied linearly with temperature from 1.9 μB at 10 K to 3.6 μB at 380 K, indicating a spin crossover behavior that involves S1/2 (predominant at T<180 K) and S3/2 (predominant at T>200 K) species. Both cobalt(II) species were detected by electron paramagnetic resonance at T<20 K. The reaction of Ge(pyrmPiPr2)2CMe2 with NiCl2(dme) (dme=dimethoxyethane) gave a square planar nickel(II) complex, NiCl{κ3P,Ge,P‐GeCl(pyrmPiPr2)2CMe2}, whereas the reaction with CuCl2 involved a redox process that rendered a mixture of the germanium(IV) compound GeCl2(pyrmPiPr2)2CMe2 and a binuclear copper(I) complex, Cu2{μ‐κ3P,Ge,P‐GeCl(pyrmPiPr2)2CMe2}2, whose metal atoms are in tetrahedral environments. The reaction of the germylene with ZnCl2 led to the tetrahedral derivative ZnCl{κ3P,Ge,P‐GeCl(pyrmPiPr2)2CMe2}.
Pincer ligands: Paramagnetic (M=FeII, CoII) and diamagnetic (M=NiII, CuI, ZnII) mononuclear (M=FeII, CoII, NiII, ZnII) and binuclear (M=CuI) complexes supported by a PGeP pincer chloridogermyl ligand have been prepared from reactions of a dipyrromethane‐derived PGeP germylene with the corresponding metal(II) chlorides.
The PGeP pincer‐type germylene Ge(NCH2PtBu2)C6H4 (1) has been used to prepare a family of group 10 metal complexes, namely, MCl{κ3P,Ge,P‐GeCl(NCH2PtBu2)2C6H4} (M=Ni (2Ni), Pd (2Pd), Pt (2Pt)), ...featuring a chloridogermyl PGeP pincer ligand and a Cl−Ge−M−Cl bond sequence. Their reactivity is not initially centered on the metal atom but on their Ge atom. Complexes 2Ni and 2Pd easily led to the hydrolyzed products Ni2Cl2{μ‐(κ3P,Ge,P‐Ge(NCH2PtBu2)2C6H4)2O}, which features a Cl−Ni−Ge−O−Ge−Ni−Cl bond sequence, and PdCl{κ3P,Ge,P‐Ge(OH)(NCH2PtBu2)2C6H4}, which contains a hydroxidogermyl PGeP pincer ligand (2Pt is reluctant to undergo hydrolysis). Simple chloride exchange reactions led to the methoxidogermyl, methylgermyl, and phenylgermyl derivatives MCl{κ3P,Ge,P‐GeR(NCH2PtBu2)2C6H4} (M=Pd, Pt; R=OMe, Me, Ph). Whereas the palladium complexes PdCl{κ3P,Ge,P‐GeR(NCH2PtBu2)2C6H4} (R=Me, Ph) reacted with more MeLi or PhLi to give palladium black and GeR2(NCH2PtBu2)2C6H4 (R=Me, Ph), similar reactions with the analogous platinum complexes afforded the transmetalation derivatives PtR{κ3P,Ge,P‐GeR(NCH2PtBu2)2C6H4} (R=Me, Ph). The short length of the CH2PtBu2 arms of the PGeP pincer ligands forces the metal atoms of all these complexes to be in a very distorted square‐planar ligand environment. The reactivity results have been rationalized with theoretical calculations.
A bunch of pincers: A family of group 10 metal complexes containing germyl PGeP pincer ligands (with the Ge atom attached to a chlorido, germyloxo, hydroxido, methoxido, methyl, or phenyl group) has been prepared from a pincer‐type PGeP diphosphanegermylene. Different reactivities (at the Ge and M atoms) have been observed for isostructural complexes differing only in the nature of the M atom.
Reactions of the first-generation Grubbs’ catalyst trans-RuCl2(CHPh)(PCy3)2 (1) with the amidinatogermylenes Ge( t Bu2bzam)R (R = t Bu (L 1 ), CH2SiMe3 (L 2 ); t Bu2bzam = ...N,N′-bis(tertbutyl)benzamidinate) have allowed the isolation and full characterization of the first specimens of Grubbs-type carbene complexes featuring heavier tetrylenes as ancillary ligands, namely, the disubstituted derivatives trans-RuCl2(CHPh)(L 1 )2 (3) and cis-RuCl2(CHPh)(L 2 )2 (7), which curiously differ in the arrangement of their germylene ligands. DFT calculations have revealed that the different volumes of L 1 and L 2 (the former is larger than the latter) are responsible for the different stereochemistry of 3 and 7. NMR-monitoring of the reaction solutions has allowed the observation of the monosubstituted intermediates trans-RuCl2(CHPh)(L)(PCy3) (L = L 1 (2), L 2 (5)) and their evolution to either the disubstituted final product (for L 1 ) trans-RuCl2(CHPh)(L 1 )2 (3) or the short-lived disubstituted intermediate (for L 2 ) trans-RuCl2(CHPh)(L 2 )2 (6). Complex 7 arises from a trans-to-cis isomerization of intermediate 6. As olefin metathesis catalysts, both 3 and 7 promoted the ring-closing metathesis of diethyl 2,2-diallylmalonate and the ring-opening metathesis polymerization of norbornene, but their catalytic activity decreased with the reaction time, indicating catalyst decomposition.
Aims
Genotype and left ventricular scar on cardiac magnetic resonance (CMR) are increasingly recognized as risk markers for adverse outcomes in non‐ischaemic dilated cardiomyopathy (DCM). We ...investigated the combined influence of genotype and late gadolinium enhancement (LGE) in assessing prognosis in a large cohort of patients with DCM.
Methods and results
Outcomes of 600 patients with DCM (53.3 ± 14.1 years, 66% male) who underwent clinical CMR and genetic testing were retrospectively analysed. The primary endpoints were end‐stage heart failure (ESHF) and malignant ventricular arrhythmias (MVA). During a median follow‐up of 2.7 years (interquartile range 1.3–4.9), 24 (4.00%) and 48 (8.00%) patients had ESHF and MVA, respectively. In total, 242 (40.3%) patients had pathogenic/likely pathogenic variants (positive genotype) and 151 (25.2%) had LGE. In survival analysis, positive LGE was associated with MVA and ESHF (both, p < 0.001) while positive genotype was associated with ESHF (p = 0.034) but not with MVA (p = 0.102). Classification of patients according to genotype (G+/G−) and LGE presence (L+/L−) revealed progressively increasing events across L−/G−, L−/G+, L+/G− and L+/G+ groups and resulted in optimized MVA and ESHF prediction (p < 0.001 and p = 0.001, respectively). Hazard ratios for MVA and ESHF in patients with either L+ or G+ compared with those with L−/G− were 4.71 (95% confidence interval: 2.11–10.50, p < 0.001) and 7.92 (95% confidence interval: 1.86–33.78, p < 0.001), respectively.
Conclusion
Classification of patients with DCM according to genotype and LGE improves MVA and ESHF prediction. Scar assessment with CMR and genotyping should be considered to select patients for primary prevention implantable cardioverter‐defibrillator placement.
Non‐ischaemic dilated cardiomyopathy (NI DCM) patients with positive genotype and/or late gadolinium enhancement (LGE) show increased risk of ventricular arrhythmias and end‐stage heart failure (ESHF) during follow‐up. CI, confidence interval; HR, hazard ratio; LVEF, left ventricular ejection fraction; MVA, malignant ventricular arrhythmia.
PDF
