Binding H 2 , N 2 , H − , and BH 3 to Transition‐Metal Sulfur Sites: Synthesis and Properties of [Ru(L)(PR 3 )(‘N 2 Me 2 S 2 ’)] Complexes (L=η 2 ‐H 2 , H − , BH 3 ; R=Cy, i Pr)

The reactions of [Ru(N 2 )(PR 3 )(‘N 2 Me 2 S 2 ’)] [‘N 2 Me 2 S 2 ’=1,2‐ethanediamine‐ N , N ′‐dimethyl‐ N , N ′‐bis(2‐benzenethiolate)(2−)] [ 1 a (R= i Pr), 1 b (R=Cy)] and [μ‐N 2 {Ru(N 2 )(P i Pr 3 )(‘N 2 Me 2 S 2 ’)} 2 ] ( 1 c ) with H 2 , NaBH 4 , and NBu 4 BH 4 , intended to reduce the N 2 ligands, led to substitution of N 2 and formation of the new complexes [Ru(H 2 )(PR 3 )(‘N 2 Me 2 S 2 ’)] [ 2 a (R= i Pr), 2 b (R=Cy)], [Ru(BH 3 )(PR 3 )(‘N 2 Me 2 S 2 ’)] [ 3 a (R= i Pr), 3 b (R=Cy)], and [Ru(H)(PR 3 )(‘N 2 Me 2 S 2 ’)] − [ 4 a (R= i Pr), 4 b (R=Cy)]. The BH 3 and hydride complexes 3 a , 3 b , 4 a , and 4 b were obtained subsequently by rational synthesis from 1 a or 1 b and BH 3 ⋅THF or LiBEt 3 H. The primary step in all reactions probably is the dissociation of N 2 from the N 2 complexes to give coordinatively unsaturated [Ru(PR 3 )(‘N 2 Me 2 S 2 ’)] fragments that add H 2 , BH 4 − , BH 3 , or H − . All complexes were completely characterized by elemental analysis and common spectroscopic methods. The molecular structures of [Ru(H 2 )(PR 3 )(‘N 2 Me 2 S 2 ’)] [ 2 a (R= i Pr), 2 b (R=Cy)], [Ru(BH 3 )(P i Pr 3 )(‘N 2 Me 2 S 2 ’)] ( 3 a ), [Li(THF) 2 ][Ru(H)(P i Pr 3 )(‘N 2 Me 2 S 2 ’)] ([Li(THF) 2 ]‐ 4 a ), and NBu 4 [Ru(H)(PCy 3 )(‘N 2 Me 2 S 2 ’)] (NBu 4 ‐ 4 b ) were determined by X‐ray crystal structure analysis. Measurements of the NMR relaxation time T 1 corroborated the η 2 bonding mode of the H 2 ligands in 2 a ( T 1 =35 ms) and 2 b ( T 1 =21 ms). The H,D coupling constants of the analogous HD complexes HD‐ 2 a ( 1 J (H,D)=26.0 Hz) and HD‐ 2 b ( 1 J (H,D)=25.9 Hz) enabled calculation of the HD distances, which agreed with the values found by X‐ray crystal structure analysis ( 2 a : 92 pm (X‐ray) versus 98 pm (calculated), 2 b : 99 versus 98 pm). The BH 3 entities in 3 a and 3 b bind to one thiolate donor of the [Ru(PR 3 )(‘N 2 Me 2 S 2 ’)] fragment and through a B‐H‐Ru bond to the Ru center. The hydride complex anions 4 a and 4 b are extremely Brønsted basic and are instantanously protonated to give the η 2 ‐H 2 complexes 2 a and 2 b .