There are least two types of negative results 1) Contradiction of previously published results. Negative results of this kind is either they are wrong, you are wrong or it depends on the differences within the experimental methods used. An example of the latter case would be SPR vs ITC. SPR for a number of protein interactions just does not work but ITC does.
2) You have developed a hypothesis, tested it and it does not work. Either that you hypothesis is wrong, which may be useful if it were published as it may stop other research groups wasting time/effort/money on an experiment that would not work in the first place. Or your experimental method is wrong. Again this maybe worth publishing as it may give someone else an idea. Though of course publishing these types of negative results may not really help you but may help your rivals/competitors. So you have to be careful.
