Stabilization of a Diphosphagermylene through pπ–pπ Interactions with a Trigonal‐Planar Phosphorus Center

Abstract

N-Heterocyclic carbenes and their heavier homologues are, in part, stabilized by delocalization of the N lone pairs into the vacant p-orbital at carbon (or a heavier Group 14 element center). These interactions are usually absent in the corresponding P-substituted species, owing to the large barrier to planarization of phosphorus. However, judicious selection of the substituents at phosphorus has enabled the synthesis of a diphosphagermylene, [(Dipp) 2 P] 2 Ge, in which one of the P centers is planar (Dipp = 2,6-diisopropylphenyl). The planar nature of this P center and the correspondingly short PÀGe distance suggest a significant degree of PÀGe multiple bond character that is due to delocalization of the phosphorus lone pair into the vacant p-orbital at germanium. DFT calculations support this proposition and NBO and AIM analyses are consistent with a Ge À P bond order greater than unity.

N,P‐Heterocyclic Germylene/B(C6F5)3 Adducts: A Lewis Pair with Multi‐reactive Sites

“…In contrast to the X-ray crystal structure of 3e,the DFToptimized geometry of cation 3a shows as ignificantly elongated Ge À P1 bond (2.342 )a nd as trongly pyramidalized geometry around the P1 atom (S8 8P1 = 3378 8), which is consistent with only aw eak or no GeÀP-p-interaction. [26,27] In fact, the calculated GeÀP1 bond length is similar to those observed for the push-spectator-type diphosphinogermylene [(Dipp 2 P) 2 Ge:] (GeÀP: 2.234 and 2.382 ). [28] In contrast, the short Ge À N1 distance (1.892 )indicates an enhanced N = Ge p-bond character.T hese calculated data suggest that germylene 3a is mainly stabilized by p-donation from the amino substituent, and the phosphino group behaves as as pectator substituent (push-spectator system)-akin to (amino)(phosphino)-carbene [29] and diphosphinogermylene.…”

N,P‐Heterocyclic Germylene/B(C6F5)3 Adducts: A Lewis Pair with Multi‐reactive Sites

“…In contrast to the X-ray crystal structure of 3e,the DFToptimized geometry of cation 3a shows as ignificantly elongated Ge À P1 bond (2.342 )a nd as trongly pyramidalized geometry around the P1 atom (S8 8P1 = 3378 8), which is consistent with only aw eak or no GeÀP-p-interaction. [26,27] In fact, the calculated GeÀP1 bond length is similar to those observed for the push-spectator-type diphosphinogermylene [(Dipp 2 P) 2 Ge:] (GeÀP: 2.234 and 2.382 ). [28] In contrast, the short Ge À N1 distance (1.892 )indicates an enhanced N = Ge p-bond character.T hese calculated data suggest that germylene 3a is mainly stabilized by p-donation from the amino substituent, and the phosphino group behaves as as pectator substituent (push-spectator system)-akin to (amino)(phosphino)-carbene [29] and diphosphinogermylene.…”

Tetranuclear Fe Clusters with a Varied Interstitial Ligand: Effects on the Structure, Redox Properties, and Nitric Oxide Activation

“…Glassware was oven dried at 140 °C for at least 2 h prior to use, and allowed to cool under vacuum. LFe 3 (OAc)(OTf) 2 , 8a Fe(N(SiMe 3 ) 2 ) 2, 21 benzyl potassium, 22 1- H -3-phenyl pyrazole (HPhPz), 23 anhydrous [NBu 4 ][F] 24 , and [(2,4-Br-C 6 H 3 ) 3 N][SbCl 6 ] 25 were prepared according to literature procedures. [(4-Br-C 6 H 4 ) 3 N][OTf] was prepared according to a modified literature procedure.…”