A Germylene Supported by Two 2‐Pyrrolylphosphane Groups as Precursor to PGeP Pincer Square‐Planar Group 10 Metal(II) and T‐Shaped Gold(I) Complexes

Abstract

An efficient synthesis of 2-di-tert-butylphosphanylmethylpyrrole( HpyrmPtBu 2 ), by treating 2-dimethylaminomethylpyrrole( HpyrmNMe 2 )w ith tBu 2 PH at 135 8Ci nt he absence of any solvent,h as allowed the preparation of the new PGeP germyleneG e(pyrmPtBu 2 ) 2 (1), by treating [GeCl 2 (dioxane)] with LipyrmPtBu 2 ,i nw hich the Ge atom is stabilized by intramolecular interactions with one (solid state) or both (solution) of its phosphane groups.R eactions of germylene 1 with Group 10 metald ichlorido complexes containing easily displaceablel igandsh ave led to [MCl{k 3 P,Ge,P-GeCl(pyrmPtBu 2 ) 2 }] [M = Ni (2), Pd (3), Pt (4)], which have an unflawed square-planar metale nvironment.Treatmento fg ermylene 1 with [AuCl(tht)] (tht = tetrahydrothiophene) rendered[ Au{k 3 P,Ge,P-GeCl(pyrmPtBu 2 ) 2 }] (5), which is ar are case of aT -shaped gold(I) complex. The hydrolysis of 5 gave the linear gold(I) derivative [Au(kP-HpyrmPtBu 2 ) 2 ]Cl (6). Complexes 2-5 contain aP GeP pincer chloridogermyl ligandt hat arises from the insertionof the Ge atom of germylene 1 into aM ÀCl bond of the corresponding metal reagent. The bondingi nt hese molecules has been studied by DFT/NBO/QTAIM calculations. These results demonstrate that the great flexibility of germylene 1 makesi tabetter precursor to PGeP pincer complexes than the previouslyk nown germylenes of this type.[a] Prof.Supporting information (containingt he experimental details and analytical, spectroscopic, structural(XRD), and theoretical (DFT,QTAIM) and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

The Transition Metal Chemistry of PGeP and PSnP Pincer Heavier Tetrylenes

“…However, germylene XXIX reacted readily with [AuCl(tht)] in THF at room temperature to give [Au{κ 3 P , Ge , P ‐GeCl(pyrmP t Bu 2 ) 2 }] ( 38 ; Figure ). Its XRD structure confirmed that the molecule arises from the insertion of the Ge atom of XXIX into the Au–Cl bond of the gold precursor, resulting in a complex containing a PGeP pincer chloridogermyl ligand attached in an uncommon T‐shape mode to the gold atom . DFT and QTAIM calculations indicated that the bonding between the Ge and Au atoms is a weak Ge→Au donor–acceptor interaction, a feature that contrasts with that found for T‐shaped PSbP pincer gold(I) complexes, in which the Au–Sb bonding is also weak but corresponds to an Au→Sb donor‐acceptor interaction (where the gold is the donor atom) …”

“…An efficient synthesis of 2‐ditertbutylphosphanylmethylpyrrole (HpyrmP t Bu 2 ), by reacting 2‐dimethylaminomethylpyrrole (HpyrmNMe 2 ) with t Bu 2 PH at 135 °C in the absence of any solvent, allowed the preparation of the PGeP germylene Ge(pyrmP t Bu 2 ) 2 ( XXIX ) by treating GeCl 2 (diox) with two equivalents of LipyrmP t Bu 2 (Figure ). The Ge atom of XXIX is stabilized by intramolecular interactions with one (solid state) or both (solution) of its phosphane groups . In the solid state, the two pyrrolyl rings of germylene XXIX are almost perpendicular to each other and the ligand environment of the Ge atom is trigonal pyramidal (tetrahedral if it is considered that one vertex is occupied by the Ge lone pair), in contrast with the coplanar (or almost coplanar) disposition of the GeP 2 N 2 atom groupings of germylenes XXV and XXVII (see above).…”

“…Aiming at comparing the reactivity of the flexible germylene XXIX with those of the much less adaptable germylenes XXV and XXVII , the reactivity of the former with groups 10 and 11 metal chlorides (or chlorido complexes) was investigated. The reactions of XXIX with group 10 metal dichlorido complexes containing easy displaceable ligands proceeded quickly at room temperature, rendering the mononuclear complexes [MCl{κ 3 P , Ge , P ‐GeCl(pyrmP t Bu 2 ) 2 }] (M = Ni ( 35 ), Pd ( 36 ), Pt ( 37 ); Figure ) . Their NMR spectra indicated symmetric and identical molecular structures and the XRD structure of 37 showed that its chloridogermyl PGeP pincer ligand allows an almost undistorted square‐planar coordination for the Pt atom (P–Pt–P angle 168.84(7)°).…”

“…Therefore, the great flexibility of germylene XXIX makes it a better precursor to PGeP pincer complexes than its antecessors XXV and XXVII . However, the smaller steric protection of the Ge atoms of XXIX and its complexes makes them more susceptible to receive nucleophilic attacks, as has been proven for the gold complex 38 , which easily extruded the Ge atom in the presence of adventitious moisture, to give [Au(κ P ‐HpyrmP t Bu 2 ) 2 ]Cl, even working with carefully dried solvents and glassware …”

“…It its noteworthy that they all have been described in the last three years. Our contributions (compounds XXV , XXVI , XXIX and XXX , 2017–2019) have been complemented with results produced by Goicoechea's (compounds XXVII and XXVIII , 2018) and Tobita's (compound XXXI , 2019) research groups.…”