Selective Substitution of One of the Substituents on Germanium in Coordinatively Unsaturated Ruthenium Germyl Complexes

Abstract

The coordinatively unsaturated tri-p-tolylgermyl complex RuCl(Ge[p-tolyl]3)(CO)(PPh3)2 (1) is obtained in good yield through the reaction between HGe(p-tolyl)3 and RuCl(Ph)(CO)(PPh3)2. On treatment of 1 with 1 equiv of NaS2CNR′2 (R′ = Et, Me), the chloride ligand is displaced and the corresponding coordinatively saturated complexes Ru(κ2-S2CNR′2)(Ge[p-tolyl]3)(CO)(PPh3)2 (2a, R′ = Et; 2b, R′ = Me) are formed. One of the PPh3 ligands in 2a is labile and undergoes substitution readily on addition of CO to give the cis-dicarbonyl complex Ru(κ2-S2CNEt2)(Ge[p-tolyl]3)(CO)2(PPh3) (3). On addition of NaS2CNMe2 to 2b, a PPh3 ligand is displaced by one sulfur atom while the other sulfur atom displaces one of the p-tolyl groups on germanium to give Ru(κ2(Ge,S)-Ge[p-tolyl]2S2CNMe2)(κ2-S2CNMe2)(CO)(PPh3) (4). Complex 4 is also formed on addition of excess NaS2CNMe2 to 1. Treatment of 1 with pyridine and ethanol under ambient conditions also results in cleavage of one of the germyl p-tolyl groups, and the product formed is the coordinatively unsaturated, ethoxy-substituted germyl complex RuCl(Ge[OEt][p-tolyl]2)(CO)(PPh3)2 (5). The ethoxy group in 5 is labile, and on contact with n-propanol in solution, alkoxy group exchange slowly occurs to give RuCl(Ge[O n Pr][p-tolyl]2)(CO)(PPh3)2 (6). This reaction is reversible, and treatment of 6 with ethanol returns 5. In a related reaction, treatment of 5 with water gives the hydroxy–germyl analogue RuCl(Ge[OH][p-tolyl]2)(CO)(PPh3)2 (7). The single-crystal X-ray structures of 1, 2a, 3, and 4 are presented.

Ruthenium and Osmium Germyl Complexes Derived from the Reactions of MXCl(PPh3)3 (M = Ru, Os; X = Cl, H) with Terphenylchlorogermylene (C6H3‐2,6‐Trip2)GeCl (Trip = 2,4,6‐iPr3C6H2)

“…The Ru(1)–Ge(1) bond length in 8 of 2.4616(5) Å is longer than that in the closely related hydrido ruthenium complex 3 [2.3918(8) Å] for the same reason. However, it is almost identical with those reported for the trialkyl or triarylgermyl complexes such as RuCl[Ge( p ‐tolyl) 3 ](CO)(PPh 3 ) 3 [2.4591(3) Å][18a] and RuCl(GeMe 3 )(CO)(PPh 3 ) 3 [2.4455(4) Å]. [24a]…”

“…This is probably due to the bulkiness of the η 6 ‐Trip group compared to benzene. The Ru–Ge bond length in 1 also falls in the range of values observed in other reported germyl complexes such as (η 5 ‐C 5 H 5 )Ru(GeH 3 )(PPh 3 )[P(OMe 3 )] [2.4421(9) Å],[13a] RuCl[Ge( p ‐tolyl) 3 ](CO)(PPh 3 ) 3 [2.4591(3) Å],[18a] RuCl(GeMe 3 )(CO)(PPh 3 ) 3 [2.4455(4) Å],[24a] and cis ‐Ru(CO) 4 (GeCl 3 ) 2 [2.481(5) Å] …”

“…A survey of the Cambridge Crystallographic Database for the Os–Ge bond lengths in terminal germyl complexes shows that the values fall in the range of 2.421–2.575 Å (a total of 13 complexes reported). [15d], [17a], [17b], [17c], [18b], , The Os(1)–Ge(1) bond length in 2 of 2.4424(8) Å is at the lower end of the values for the reported complexes: close to that of the Os IV –germyl complex {η 5 ‐C 5 H 4 ‐N(CH 2 CH=CH 2 ) 2 }OsH 2 (GePh 3 )(P i Pr 3 ) (2.45967 Å),[26a] but slightly shorter than the bond lengths observed in the Os IV –germyl complex (η 5 ‐C 5 H 5 )OsH(C≡CPh)(GePh 3 )(P i Pr 3 ) (2.50334 Å)[26b] and the cyclic osmium(II)–bis(germyl) complex Os[GeCl 2 (OH)GeCl 2 (OH)GeCl 2 ][P(OEt) 3 ] 4 [2.5047(15) Å and 2.5112(16) Å] …”

“…Closely related to germylene and germylyne complexes are transition‐metal germyl complexes, which have been known for a long time and have continuously received considerable attention over the last several decades, mainly because of their relevance to the catalytic transformations involving germanium, and materials chemistry. [12a], The most versatile methods for the synthesis of transition‐metal germyl complexes involve either oxidative addition of the Ge–X bond GeXR 3 (X = H, Cl)[12a], or insertion of dihalogen species GeX 2 into the M–X bond[12a], [13a], , to give triorgano M‐GeR 3 or trihalogen M‐GeX 3 germyl derivatives. However, despite of the large number of germyl complexes of transition metals that have been prepared in recent years, ruthenium germyl complexes are still much less common,[13a], [15c], , , while the osmium congeners are even more limited , , , …”

[Ge(H)(2‐C6H4PPh2)3] as Ligand Precursor at Ruthenium: Formation and Reactivity of [Ru(Cl){Ge(2‐C6H4PPh2)3}]

“…The parameter τ is defined to be close to zero for square‐pyramidal structures and is equal to unity for a trigonal‐bipyramidal geometry 18. The Ge1–Ru1 bond length of 2.3695(3) Å is at the shorter end of Ge–Ru distances, which are reported in the literature, such as in [Ru(Cl)(GeMe 3 )(CO)(PPh 3 ) 2 ] [2.4455(4) Å]19 or in [Ru(Cl){Ge(4‐C 6 H 4 CH 3 ) 3 }(CO)(PPh 3 ) 2 ] [2.4591(3) Å] 20…”