Reactions of Late First-Row Transition Metal (Fe-Zn) Dichlorides with a PGeP Pincer Germylene

The reactivity of the PGeP germylene 2,2'-bis(di-isopropylphosphanylmethyl)-5,5'-dimethyldipyrromethane-1,1'-diylgermanium(II), Ge(pyrmPiPr(2))(2)CMe2, 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{kappa P-3,Ge,P-GeCl(pyrmPiPr(2))(2)CMe2}] (M=Fe, Co). While the iron complex maintained an intermediate spin state (S-1; mu(eff)=3.0 mu(B)) over the temperature range 50-380 K, the effective magnetic moment of the cobalt complex varied linearly with temperature from 1.9 mu(B) at 10 K to 3.6 mu(B) at 380 K, indicating a spin crossover behavior that involves S-1/2 (predominant at T<180 K) and S-3/2 (predominant at T>200 K) species. Both cobalt(II) species were detected by electron paramagnetic resonance at T<20 K. The reaction of Ge(pyrmPiPr(2))(2)CMe2 with [NiCl2(dme)] (dme=dimethoxyethane) gave a square planar nickel(II) complex, [NiCl{kappa P-3,Ge,P-GeCl(pyrmPiPr(2))(2)CMe2}], whereas the reaction with CuCl2 involved a redox process that rendered a mixture of the germanium(IV) compound GeCl2(pyrmPiPr(2))(2)CMe2 and a binuclear copper(I) complex, [Cu-2{mu-kappa P-3,Ge,P-GeCl(pyrmPiPr(2))(2)CMe2}(2)], whose metal atoms are in tetrahedral environments. The reaction of the germylene with ZnCl2 led to the tetrahedral derivative [ZnCl{kappa P-3,Ge,P-GeCl(pyrmPiPr(2))(2)CMe2}].

Automated summary

The reactivity of PGeP germylene with late first-row transition metal dichlorides has been investigated, leading to the formation of various pincer chloridogermyl complexes. Different transition metals resulted in different paramagnetic or square planar complexes, indicating a variety of spin states and behaviors. Reactivity with NiCl2 and CuCl2 also produced different complexes, showcasing a versatile reactivity of the germylene compound.