The phrase "are particularly grateful" is correct and usable in written English.
You can use it when expressing a strong sense of appreciation or thankfulness towards someone or something.
Example: "We are particularly grateful for the support we received during the challenging times."
Alternatives: "are especially thankful" or "are deeply appreciative".
"We are particularly grateful to Liza Minnelli, for whom we would gladly post bail," she read.
We are particularly grateful to Professor Bruce Land for his help and guidance throughout FALL 2015 semester.
We are particularly grateful for Liberty's efforts in spearheading this litigation and making it possible for this information to be brought to light".
One feature of iTunes Radio that music companies are particularly grateful for is a prominent button to buy a song as it streams.
We are particularly grateful for our colleagues across the world who supported the Guardian in circumstances which threatened to stifle our reporting.
We are particularly grateful for his caring generosity in helping enrich the cultural lives of the Jewish blind and visually impaired home we serve.
We are particularly grateful to Ilse Lanz and Martina Ofner for their excellent technical assistance that they provided with numerous assays.
We are particularly grateful for assistance of the staff of the IODP Core Repository in Bremen, Germany for their assistance taking these samples and running shipboard analyses.
We are particularly grateful for Dr. Chopra who opened up the center to research and supported all aspects of the endeavor.
"We are particularly grateful to officers of the NSW police Griffith area local command, who let our family know before the search was about to begin and then ensured that we were aware of progress".
We are particularly grateful that Dunn and Smyth (2005) and Zhang (2013) chose to produce R programs for implementation of the Tweedie family of model distributions.
