see link

http://link.springer.com/referenceworkentry/10.1007%2F978-94-007-0753-5_1493

Dear Omar

first of all you didn't mention the number of items you used, so alpha sometimes might be missleading because of its sensitivity of test lenght and in this case inter item corr. behave better, researcher argued that mean interitem corr considered as an acceptable value when it in the range 0.2-0.4

but negative values mean a weak correlations between items which surely affect Cronbach's alpha value

See the excellent article "Qual a fiabilidade do alfa de Cronbach? Questões antigas e soluções modernas?" of João Maroco e Teresa Garcia-Marques. Laboratorio de Psicologia, 4(1):65-90 de 2006.

Is it ok if my inter-item correlation matrix got negative value though my cronbach alpha value is 0.735? Thanks

Bernice, no, it's not okay. "Check the Inter-Item Correlation Matrix for negative values. All values should be positive, indicating that the items are measuring the same underlying characteristic. The presence of negative values could indicate that some of the items have not been correctly reverse scored. Incorrect scoring would also show up in the Item-Total Statistics table with negative values for the Corrected-Item Total Correlation values. These should be checked carefully if you obtain a lower than expected Cronbach alpha value. (Check what other researchers report for this scale.)" SPSS Survival Manual, Julie Pallant, 2016

Indeed yes !: such a low correlation indicates that THE MINIMUM THRESHOLD OF RELIABILITY EXPECTED AND ACCEPTABLE.