A cumulene is a hydrocarbon with three or more cumulative (consecutive) double bonds. A member of this compound class is butatriene (which is also called simply cumulene), H2C=C=C=CH2. Unlike most alkanes and alkenes, cumulenes tend to be rigid, which makes them appealing for molecular nanotechnology. Polyynes are another kind of rigid carbon chains. Cumulenes are found in regions of space where hydrogen is rare (see astrochemistry). Cumulenes containing heteroatoms are called heterocumulenes. An example is carbon suboxide.
The first reported synthesis of a butatriene is that of tetraphenylbutatriene in 1921. The most common synthetic method for butatriene synthesis is based on reductive coupling of a geminal dihalovinylidene. Tetraphenylbutatriene was reported synthesized in 1977 by homocoupling of 2,2-diphenyl-1,1,1-tribromoethane with elemental copper in dimethylformamide.
The rigidity of cumulenes arises from the fact that the internal carbon atoms carry two double bonds. Their sp hybridisation results in two bonds separated by 90°. Cumulenes with (1) an even number of consecutive double bonds and (2) dissimilar substituents on either end can be chiral even though they lack a classical stereocenter. On the other hand odd numbers of double bonds in a cumulated system with proper substituents show cis-trans isomerism.
Tell him why you act this way
You get the text and turn away
He thought you were locked in love
Is the lock un-done?
Tell him why you blank his calls
You're slowly, surely building walls
That he can't climb, he's left behind...
Sometimes girls lie
That's when boys cry
A single tear is all it takes
To show how bad his heart aches
Sometimes girls lie
That's when boys cry
Another lie to be believed
Another result you have achieved
He thinks he's big, he thinks he's strong
But you've been lieing all along
If only he knew your secret way
Tell him 'move on, or choose stay'
I know, you wont leave him... never
I'm left wanting you forever
Now I'm left out on the side
The 'other boy' you tried you hide...
Sometimes girls lie
That's when boys cry
A single tear is all it takes
To show how bad his heart aches
Sometimes girls lie
That's when boys cry
Another lie to be believed
Another result you have achieved
So now the weeks have past
And time has gone
No message, no text, no call at all...
Sometimes girls lie
That's when boys cry
A single tear is all it takes
To show how bad his heart aches
Sometimes girls lie
That's when boys cry
Another lie to be believed
Another result you have achieved
Sometimes girls lie
That's when boys cry
A single tear is all it takes
To show how bad his heart aches
Sometimes girls lie
That's when boys cry
We had our time; I'll fade away