On a recent sunlit morning in Brooklyn, Leonard Petlakh drove me on a tour of the synagogues that pepper the heavily Russian-speaking neighbourhoods of south Brooklyn.

"Another congregation, happily dying," Mr Petlakh said, pulling up outside the Conservative Congregation Beth Shalom, where he was married 11 years ago.

"If you go down any street around here most of the homes are Russian," he continued. "But the synagogue's boards aren't interested in outreach to Russians."

It has been 20 years since the last great wave of Russian-speaking Jews - about 300,000 people, says Mr Petlakh - began to arrive in New York. Yet, for the most part, they have failed to fit in.

Though the barriers to assimilation, such as language and socio-economic divisions, have fallen, there is still a gap between American and former Soviet Jews.

The gap can be discerned in the separate events put on to attract Russian-speaking Jews, such as New York's Limmud FSU. And in the fact that many struggling New York synagogues can be found at the centre of large, Russian-speaking populations.

To illustrate this, Mr Petlakh, a community leader, gave me a tour of the middle-class neighbourhoods of Mill Basin, Manhattan Beach and Sheepshead Bay, a stone's throw from the Soviet-immigrant portal of Brighton Beach.

In the midst of these large Russian-speaking populations are more than a handful of Conservative and Modern Orthodox shuls.

He explained that the board of many of the established synagogues are comprised of elderly Americans whose children have moved away.

They provide few programmes for young families. Most rabbis are not attuned to the needs of the Russian-speaking community.

"It's not about buildings," Mr Petlakh said. "It's about people. A couple of rabbis would change the landscape here."

Though Russian-speaking Jews are notoriously ambivalent about attending synagogue, Mr Petlakh said most want to raise Jewish children.

"When you have no religious reason to be in a synagogue, you are looking for a social network," said Mr Petlakh. "And this," he indicated an elderly man shuffling out of the shul, "is not your social network." Mr Petlakh was appointed executive director of the Kings Bay Y, a local Jewish community and sports centre, almost four years ago.

He said that when he took over the Y it suffered the same problems as local shuls - an ageing board and few programmes that appealed to young Russian families.

Mr Petlakh introduced items for children and teens, such as Jewish-themed art classes and Israeli dancing. He also supervised the twinning of Kings Bay Y with communities in Holon, Israel, and in Munich, Germany. Now, young couples from each place visit each other annually.

Since Mr Petlakh arrived, the Y's annual budget has doubled from $2.5 million to $5 million.

He said that his dream is for more Russian-speaking Jews to join existing Jewish entities and change them.

"We need to build a sustainable model for Russian-speaking families," he said. "And that can only be done within the religious and financial framework of the American Jewish community."