Unusual coordination mode for 1,3-diphosphete ligands towards a Cr-Cr quintuple bond complex

The reaction of (LCrCrL)-Cr-5 (L = N2C25H29, 1) with the phosphaalkynes R-C P (R = tBu, Me, Ad) yields the neutral dimerisation compounds [L2Cr2(mu,eta(1): eta(1): eta(2): eta(2)-P2C2R2)] (R = tBu (2), Me (3)) and the tetrahedrane complex [L2Cr2(mu,eta(2): eta(2)-P = CAd)] (4). The 1,3-diphosphete ligands in complexes 2 and 3 are the first to possess this structural feature spanned over a metal-metal multiple bond, while the slightly bigger adamantyl phosphaalkyne remains a monomer in 4 with a side-on coordination mode.

Automated summary

The reaction between (LCrCrL)-Cr-5 (L = N2C25H29, 1) and phosphaalkynes R-C P (R = tBu, Me, Ad) leads to the formation of neutral dimerization compounds [L2Cr2(mu,eta(1): eta(1): eta(2): eta(2)-P2C2R2)] (R = tBu (2), Me (3)) and tetrahedrane complex [L2Cr2(mu,eta(2): eta(2)-P = CAd)] (4). The 1,3-diphosphete ligands in complexes 2 and 3 exhibit a structural feature spanning a metal-metal multiple bond, while the larger adamantyl phosphaalkyne in compound 4 remains a monomer with side-on coordination mode.