Isolation of a Heavier Cyclobutadiene Analogue: 2,4-Digerma-1,3-diphosphacyclobutadiene

The heavier cyclobutadiene analogue 2,4-digerma-1,3-diphosphacyclobutadiene ([(L2Ge2P2)-Ge-1], 4; L-1 = CH{(CMe)-(2,6-'Pr2C6H3N)}(2)), featuring a planar Ge2P2 four-membered ring, has been synthesized via the elimination of carbon monoxide from the corresponding phosphaketenyl germylene [(LGePCO)-Ge-1] (2) under UV irradiation.