Dianionic Mononuclear Cyclo‐P4 Complexes of Zero‐Valent Molybdenum: Coordination of the Cyclo‐P4 Dianion in the Absence of Intramolecular Charge Transfer. Issue 43 (10th September 2019)

• Record Type: Journal Article
• Authors: Mandla, Kyle A.; Neville, Michael L.; Moore, Curtis E.; Rheingold, Arnold L.; Figueroa, Joshua S.
• Is Part Of: Angewandte Chemie international edition. Volume 58:Issue 43(2019)
• Page Start: 15329
• Page End: 15333
• Publication Date: 2019-09-10
• Subjects: aromaticity -- cyclo-P4 -- isocyanide -- molybdenum -- phosphorus; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201908885
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Relative to other cyclic poly‐phosphorus species (that is, cyclo ‐P n ), the planar cyclo ‐P4 group is unique in its requirement of two additional electrons to achieve aromaticity. These electrons are supplied from one or more metal centers. However, the degree of charge transfer is dependent on the nature of the metal fragment. Unique examples of dianionic mononuclear η 4 ‐P4 complexes are presented that can be viewed as the simple coordination of the [ cyclo ‐P4 ] 2− dianion to a neutral metal fragment. Treatment of the neutral, molybdenum cyclo ‐P4 complexes Mo(η 4 ‐P4 )I2 (CO)(CNAr Dipp2 )2 and Mo(η 4 ‐P4 )(CO)2 (CNAr Dipp2 )2 with KC8 produces the dianionic, three‐legged piano stool complexes, [Mo(η 4 ‐P4 )(CO)(CNAr Dipp2 )2 ] 2− and [Mo(η 4 ‐P4 )(CO)2 (CNAr Dipp2 )] 2−, respectively. Structural, spectroscopic, and computational studies reveal a similarity to the classic η 6 ‐benzene complex (η 6 ‐C6 H6 )Mo(CO)3 regarding the metal‐center valence state and electronic population of the planar‐cyclic ligand π system. Abstract : More charge, more clarity : Like the cyclobutadiene dianion, the cyclic, polyphosphorus cyclo ‐P4 dianion creates an electronic structure ambiguity when found in neutral transition‐metal complexes. Dianionic cyclo ‐P4 complexes are presented that can be viewed as the simple binding of [ cyclo ‐P4 ] 2− to a metal.